The 50th Anniversary Meeting of The Israel Chemical Society 11
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' - / • The 50th Anniversary Meeting of The Israel Chemical Society 1. ! I lNlS-mf--9740 .) ·e.ro3469 o34 11- 8' TP. SO ;-: The 50th Anniversary he Israel 01 Meeting · aI Society ChelDi
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Transcript of The 50th Anniversary Meeting of The Israel Chemical Society 11
' - / •
The 50th AnniversaryMeeting of The Israel
Chemical Society
1.
! I
lNlS-mf--9740
.)
·e.ro3469 '~ o34 ~ 11- 8' JוTP.
של SOה-יובלכנסהחברה~;'הישראלית
לכימיה
;-:
The 50th Anniversary he Israel 01ז Meeting
· aI Society ~ ChelDi
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In collaboration with :Israel Institute of Chemical EngineersSociety of Chemical Industry Engineers
The Hebrew University of JerusalemApril 10—12, 1984
THE 50th ANNIVERSARY MEETING OF THEISRAEL CHEMICAL SOCIETY
~. chem;c :\ ~ . ~ s.'י \ . .--' .. ~
ff ,.)י": ~ ,~
J; <ת i'"Iנןאי
החברהשל SOה-זובלכבשלכימזההישראלית
THE 50th ANNIVERSARY MEETING OF THE
ISRAEL CHEMICAL SOCIETY
ןתקציריםתכנית
PROGRAM & ABSTRACTS
:עםבשיתיףכיסיתלהנדסההישראליתהאגודה
תעשייתיתלכיסיההאינג'ינריםאיגוד
In collaboration with : Israel Instltute of Chemlcal Englneers
Soclety of Chemical Industry Engineers
בירושליםהעבריתהאוניברסיטה
תשמ"דניסןחי-'י
~ The Hebrew Unlverslty of Jerusalem I ~
. Aprll 10-12, 1984 r בישראלכימיתוהנדסהכימיהאיריעיחידש
ו------------~--_.-
•
~
1
\
C O N T E N T S
Page
Organizing Committee 3
Sponsorship 4
Financial Support 5
Exhibitors 6
Timetable 9
Scientific Program 11
General Information 22
Abstracts 25
Author Index 215.. !
! !
t
CONTENTS
Organizing Committee
Sponsorship
Financial Support
Exhibitors
Timetable
Scientific Program
General Information
Abstracts
Author Index
עמוד
3
4
5
6
7
11
20
25
215
העניינים תוכו
המארגנת הוועדה
חסות
תרימית
בתעריכה Iמציגים
זמניםלוח
המדעיתהתוכנית
כללימידע
תקצירים
מחבריםאינדקס
Page
3
4
5
6
9
11
22
25
215
ORGANIZING COMMITTEE
H. Levanon, Chairman, The Hebrew University of Jerusalem
D. Avnir, The Hebrew University of Jerusalem
A. Bino, The Hebrew University of Jerusalem
A. Goldblum, The Hebrew University of Jerusalem
I. Goldberg, Tel-Aviv University
Z. Goldschmidt, Bar-llan University
B. Gerber, The Hebrew University of Jerusalem
F. Herbstein, Technion — Israel Institute of Technology
B.Z. Weiner, Teva Pharmaceutical Industries Ltd.
Y. Hodara, Nuclear Research Center — Negev
G. Metzger, National Council for Research & Development
M. Folman, Technion — Israel Institute of Technology
H. Feilchenfeld, The Hebrew University of Jerusalem
D. Kost, Ben-Gurion University of the Negev
M. Rablnovitz, The Hebrew University of Jerusalem
M. Shapiro, The Weizmann Institute of Science
המארגנתהייעדה
בירושליםהע,בריתהאוניברסיסהיו"ר,לנבין,ח.
בירושליםהעבריתהאוניברסיסהאנביר,ד.
בירושליםהעבריתהאוניברסיסהיב\נ,א.
)1 • u ,בירושליםהעבריתהאוניברסיסהלדלביס
תל-אביבאוניברסיסתגתדבר,גי.
בר-אילןאוניברסיסתגילוחמידס,ו.
בירושליםהעבריתהאוניברסיסהגרבר,ב.
לישראלסכנולוגימכון-.הסכניוןחרשבסייו,פ.
בע"מפרמצטביותתעשיותסעבויינר,בו.Oב
ננב-נרעינילמחקרקריהחידרח,י.
ולפיתוחלמחקרהלאימיתהמיעצהמבוונ,.ג
לישראלסכנולוגימכון-הסכניוןיולמו,מ.
בירושליםהעבריתהאוניברסיסהפיילכנפלד,ח.
בננבברגוריוןאוניברסיסתקיסס,ד.
בירושליםהעבריתהאוניברסיסהריבנוביץ,מ.
למדעייצמןמכון.פירא,מ.
ORGANIZING COMMITTEE
lem םn, The Hebrew Un:versity of Jerus םirm םH. Levanon, Ch
D. Avnlr, The Hebrew University of Jerusalem
lem םA. Blno, The Hebrew University of Jerus
lem םA. Goldblum, The Hebrew University of Jerus
1. Goldberg, Tel-Aviv University
n University םr-II םZ. Goldschmldt, B
lem םB. Gerber, The Hebrew Univers:ty of Jerus
el Institute of Technology םF. HerblteJn, Technion - Isr
. I Industries Ltd םrmaceutic םB.Z. Welner, Teva Ph
rch Center - Negev םr Rese םY. Hodara, Nucle
I Council for Research & Development םtion םG. Metzger, N
el Institute of Technology םM. Folman, Technion - Isr
H. Fellchenf.ld, The Hebrew University of Jerusalem
D. KOlt, Ben-Gurion University of the Negev
M. Rablnovltz, The Hebrew Unlversity of Jerusalem
M. Ihaplro, The Welzmann Institute of Science
-3
- .
SPONSORSHIP
The Hebrew University of Jerusalem
The Israel Academy of Sciences and Humanities
The Belfer Center for Energy Research
National Council for Research & Development
The Weizmann Institute of Science
The Ernst David Bergmann Science Foundation
Technlon — Israel Institute of Technology
The Fritz Haber Research Center for Molecular Dynamics
Tel-Aviv University
The Casali Foundation
Atomic Energy Commission
Ben-Gurion University of the Negev
Everyman's University
Bar-llan University
תחסן
בירושליםהעבריתהאוניברסיסה
למדעיםהישראליתהלאומיתהאקדמיה
האנרגיהלמחקרבלפרמרכז
ולפיתוחלמחקרהלאומיתהמועצה
למדעויצמומכון
למדעברגמןדוידארנססקרן
לישראלסכנולוגימכון-הסכניון
מולקולריתבדינמיקהלמחקרהברפריץמרכז
תל-אביבאוניברסיסת
קזאלימוסד
אסומיתלאנרגיההועדה
בנגב"-גוריון Iבאוניברסיסת
הפתוחההאוניברסיסה
בר-אילןאוניברסיסת
SPONSORSHIP
"1 I
The Hebrew University of Jerusalem
The Israel Academy of Sciences and Humanities
The Belfer Center for Energy Research
National Council for Research & Development
The Weizmann Institute of Science
The Ernst David Bergmann Science Foundation
Techn:on - Israel Institute of Technology
The Fritz Haber Research Center for Molecular Dynamics
Tel-Aviv University
The Casali Foundation
Atomic Energy Commission
Ben-Gurion University of the Negev
Everyman's University
Bar-I\an University
-4-
FINANCIAL SUPPORT
Israel Chemical Industries Ltd.
Koor Chemicals Ltd.
Bank Hapoalim B.M.
"Gadot" Chemical Tankers & Terminals Ltd.
Dor Chemicals Ltd.
Abie Ltd.
Haifa Chemicals Ltd.
Paz Oil Company Ltd.
"Delek" The Israel Fuel Corporation Ltd.
Teva Pharmaceutical Industries Ltd.
Koffolk Ltd.
Shamtan Chemicals & Lubricants Ltd.
Oil Refineries Ltd.
תרימית
בע"מלישראלכימיקלים
בע"מכימיהכור
בע"מהפועליםבנק
בע"מלחימיקליםומאגריםמיכליות"גדות"
בע"מכימיקליםדור
בע"מאביק
בע"מכימיקליםחיפה
בע"מנפטחברתפז
בע"מהישראליתהדלקחברת"דלק"
בע"מפרמצבטיותתעשיותטבע
בע"מקופולק
בע"מוכימיקליםסיכהמוצרישמטן
בע"מלנפטזיקוקבתי
FINANCIAL SUPPORT
. Israel Chemical Industries Ltd
. Koor Chemicals Ltd
. Bank Hapoalim B.M
. Gadot" Chemical Tankers & Terminals Ltd "
. Dor Chem:cals Ltd
. Abic Ltd
. Haifa Chemicals Ltd
. il Company Ltd סPaz
. Delek" The Israel Fuel Corporation Ltd "
. Teva Pharmaceutical Industries Ltd
. Koffolk Ltd
. Shamtan Chemicals & Lubricants Ltd
. il Refineries Ltd ס
-5-
_ _______ • _____ ...... ..נ-._ ~ ••
-.
-
~)~
EXHIBITORS
Eldan Electronic Instrument Co. Ltd.ISI. Israel Scientific Instruments Ltd.Eastronics Ltd.El-Hama Marketing (1972) Ltd.Ankor Scientific Equipment & Services Ltd.APA — Advanced Technologies Ltd.Bio-Instrument Ltd.Gestetner (Israel) Ltd.Heiliger & Co."Chemorad" Ltd. — Chemicals for Laboratory and IndustryYozma Computers & Software (1982) Ltd.Isramex Ltd.Lidex Corporation Ltd.Landseas (Israel) Ltd."Mada" Scientific Instruments Ltd.Makhteshim — AganIntegrated Systems Ltd.M. Kochn & Co. Ltd.Mercury Chemical Agencies Ltd.Saifan Precision Instruments Ltd.Fried Electric Ltd.Carmira Ltd.
בתערוכהמציגים
• • בע"מאלקסרוניציודו-לדן
בע"מלישראלמדעימכשוראי.אס.אי.,
בע"מאיססרוניקס
בע"מ ) 1972 (שיווקאל-חמה
בע"ממדעייםושירותיםציודאנקור
בע"ממתקדמותסכנולוגיות-אפא
בע"מביראינססרומנס
בע"מ(ישראל)גסססנר
ושות'היי-ליגר
למעבדותוציודכימיקלים-בע"מ"ח-מורד"
בע"מ ) 1982 (ותכנהמחשביםיוזמה
בע"מישראמקסחברת
בע"מלידקס
בע"מלנדסיס
בע"מאינססרומנסססאיינסיפיק"מדע"
אנו-מכתשים
בע"ממשולבותמערכות
בע"מושות'קוכןמ.
בע"מכימיקליםנציגויותמרקורי
בע"מדיוקמכשיריסייפן
בע"מאלקסריקפריד
בע"מקרמירה
EXHIBITORS
Eldan Electronic Instrument Co. Ltd. ISI. Israel Scientific Instruments Ltd. Eastronics Ltd. EI-Hama Marketing (1972) Ltd. Ankor Scientif:c Equipment & Servicas Ltd. APA - Advanced Technologies Ltd. Bio-Instrument Ltd. Gestetner (Israel) Ltd. Heillger & Co. "Chemorad" Ltd. - Chemlcals for Laboratory and Industry Yozma Computers & Software (1982) Ltd. Isramex Ltd. Lidex Corporation Ltd. Landseas (Isroel) Ltd. "Mada" Scientific Instruments Ltd. Makhteshim - Agan Integrated Systems Ltd. M. Kochn & Co. Ltd. Mercury Chemical Agencies Ltd. Saifon Precision Instruments Ltd. Fried Electric Ltd. Carmlra Ltd.
-6-
..זמניםליחרםג·בעתבקמפוסיןזקיימוהכנסישיבותכל
~ירוש,יםהעבריתהאוניברסיטהשל
1984באפריל 10 .•תשמ"דניסוח'שלישי,ירם
08.30
19.00-09.00
10.40-10.00
11.15-10.40
11.45-11.15
12.45-11.45
14.30-12.45
15.20-14.30
16.00-15.30
17.30-16.00
17.30-16.00
18.45-17.45
19.30
, ו~יז i ':;נב-הכנסחומרוחלוקתהרשמה
ושפרינצקוייזאכסדרות-מדעיציודתערוכת
וייזאודיטוריום-הפתיחהטקס
ןייזאודיטוריום- Aפתיחההרצאת
קפההפסקת
וייזאודיטוריום- Bמליאההרצאת
צהרייםהפסקת
שפרינצקבניין-מקבילותישיבות
115חדר Tl'שיבה 214חדר T2~שיבה T3ישיבה T4ישיבה T5ישיבה
117חדר 29חדר 217חדר
קפההפסקת
ושפרינצקוייזאכסדרות- Tפוסטריםתצוגת
1 .... :'כ~~ :וייזאכסדרת-סדנה
וייזאודיטורי'וס- Cמליאההרצאת
ישראלמוזיאון-מזנוןארוחתקבלת-נפים,
ישראלבמוזיאוןביקור
1914באפריל 11תשמ"ד,ניסוס'רביעי,ירם
08.00
18.30-08.30
09.30-08.30
10.30-09.30
11.00-10.30
12.30-11.00
11.50-11.00
-14.00ג 2.30
וייזבניין-(המשך)הרשמה
ושפרינצקוייזאכסדרותמדעיציודתערוכת
oמליאההרצאת Eמליאההרצאת
וייזאודיטוריום
וייזאודיטוריום
קפההפסקת
28חדר- Aרב-שיח
שפרינצקבנייןמקבילותישיבות
115חדר Wlישיבה 117חדר W2ישיבה 214חדר W3ישיבה 217חדר W4ישיבה
צהרייםהפסקת
-7-
----~י!ייייייייי~~!יייי!י-~-~_'"!:,~-"'
(המשך) 1984באפויל 11שמ"ד, JIניסוטיוביעי,יים
14.50-14.00
15.30-15.00
'שפרינצקבניין-מקבילותישיבות
214חדר W5ישיבה
115חדר W6ישיבה
117חדר W7ישיבה
217חדר W8ישיבה
קפההפסקת
ושפרינצקוייזאכסדרות- Wפוסטריםתצונת 17.30-15.30
וייזאכסדרת(המשך)סדנה 17.30-15.30
וייזאודיטוריום- Fמליאההרצאת 18.30-17.30
פינקוסאולםהאומה,בנייני-חניניתערבארוחת 19.30
הארוחה""אחריהרצאת
1984באפויל 1%,תשמ"ד,ניס'ויוחמישי,יים
ושפרינצקוייזאכסדרותמדעיציודתערוכת 18.00-08.30
וייזאודיטוריום Gמ;יאההרצאת 09.30-08.30
וייזאודיטוריום Hמליאההרצאת 10.30-09.30
קפההפסקת 11.00-10.30
וייזאודיטוריום- Bרב-שיח 13.00-11.00
צהרייםהפסקת 14.30-13.00
וייזאודיטוריום- 1מליאההרצאת 15.30-14.30
קפההפסקת 16.00-15.30
וייזאודיטוריום- Jמליאההרצאת 17.00-16.00
וייזאודיטוריום-נעילהישיבת 17.30-17.00
מקוא
וייזאודיטוריום = Wאודיטוריום
שפרינצקבניין =שפרינצק
ושפרינצקוייזאכסדרות = W + Sאכסדרות
שפרינצקבבנייוחדר = S-OOOחדר
-8-
TIMETABLE
ill ba held at the Givat Ram Campus \יוAli sessions
of the Hebrew University of Jerusalem
TUESDAY, APRIL 10, 1984
Registration and distribution of material - Wise Building
Exhibition of Scientific Equipment - Foyers Wise & Spriniak
Opening Ceremony Auditorium Wise
Opening Lecture A - Auditorium Wise
Coffee Break
Plenary Lecture B - Auditorium Wise
Lunch Break
Parallel Sessions - Sprinzak Building
5ession T1 Room 5·115 Room 5·214 Room 5·117 Room S-29 Room 5-217
5ession T2 5ession T3 5ession T4 5ession T5
Coffee Break
Poster Session T - Foyers Wisa & 5prinzak
Workshop - Foyer Wise
Plenary Lecture C - Auditorium Wise
Reception, Buttet Dinner - Israel Museum Visit ot Israel Museum
08.30
09.00-19.00
10.00-10.40
10.40-11.15
11.15-11.45
11.45-12.45
12.45-14.30
14.30-15.20
15.30-16.00
16.00-17.30
16.00-17.30
17.45-18.45
19.30
WEDNESDAY, APRIL 11, 19M
Registration (cont'd) - Wise BUilding
Exhibition of 5cientific E:qi.Aipment - Foyers Wise & 5prinzak
Plenary Lecture D Auditorium Wise
Plenary Lecture E - Auditorium Wise
Coffee Break
5-28 5ymposium A - Room
Parallel 5ess:ons - Sprinzak Building
Room S-115 Session W1 Room 5ession W2 $· 1ך 7 Room $· 2ך 4
217 ·$ Room 5ession W3 Session W4
!.unch Break
-9-
08.00
08.30-18.30
08.30-09.30
09.30-10.30
10.30-11.00
11.00-12.30
11.00-11.50
12.30-14.00
"-
-. t
WEDNESDAY, APRIL 11, 1984 (cont'd)
14.00—14.50 Parallel Sessions — Sprinzak Building
Session W5 — Room S-214
Session W6 — Room S-115
Session W7 — Room S-117
Session W8 — Room S-217
15.00—15.30 C o f f e e B r e a k
15.30—17.30 Poster Session W — Foyers Wise & Sprinzak
15.3CJ—17.30 Workshop (cont'd) — Foyer Wise
17.30—18.30 Plenary Lecture F — Auditorium W:se
19.30 Gala Dinner — Binyanei Ha'ooma, Pincus HallAfter-Dinner Lecture
THURSDAY, APRIL 12, 1984
08.30—18.00 Exhibition of Scientific Equipment — Foyers Wise & Sprinzak
08.30—09.30 Plenary Lecture G — Auditorium Wise
09.30—10.30 Plenary Lecture H — Auditorium Wise
10.30—11.00 C o f f e e B r e a k
11.00—13.00 Symposium B — Auditorium Wise
13.00—14.30 L u n c h B r e a k
14.30—15.30 Plenary Lecture I — Auditorium Wise
15.30—16.00 C o f f e e B r e a k
16.00—17.00 Plenary Lecture J — Auditorium Wise
17.00—17.30 Closing Session — Auditorium Wise
Legend
Auditorium W = Auditorium Wise
Sprinzak = Sprinzak Building
Foyers W + S = Foyers Wise + Sprinzak
Room S-000 = Room at Sprinzak Building
— 10 —
WEDNESDAY, APRIL 11, 1984 (cont'd)
14.00-14.50 • Parallel 5essions - 5prinzok Building
5ession W5 Room 5-214
5ession W6 Room 5-115
Room 5-117
Room 5-217
5ession W7
5ession W8
Coffee Break
Foyers Wise & 5prinzak Poster 5ession W
Foyer Wise
Auditorium W'se
Workshop (cont'd)
Plenary Lecture F
Gala Dinner - Binyanei Ho'ooma, Pincus Holl After-Dinner Lecture
15.00-15.30
15.30-17.30
15.30-17.30
17.30-18.30
19.30
Exhibition of 5cientific Equipment - Foyers Wise & 5prinzak
THURSDAY, APRIL 12, 1984
Auditorium Wise Plenary Lecture G
Plenary Lecture H
Coffee Break
Auditorium Wise
5ymposium B - Auditorium Wise
Lunch Break
Auditorium Wise יPlenary Lecture
Coffee Break
Plenary Lecture J - Auditorium Wise
Closing 5ession - AUditorium Wise
08.30-18.00
08.30-09.30
09.30-10.30
10.30-11.00
11.00-13.00
13.00-14.30
14.30-15.30
15.30-16.00
16.00-17.00
17.00-17.30
Legend
Auditorium W = Auditorium W:se
5prinzak = 5prinzak Building
Foyers W + 5 = Foyers Wise + 5prinzak
Room 5-000 = Room ot 5prinzok Building
-10 -
~ --------_ .. ~._-----~_ .......
SCIENTIFIC PROGRAM an>7»n
TUESDAY, APRIL 10. 1984 — V'taVI)
10.00—10.40
Auditorium W mnwniNOPENING CEREMONY
H. Levanon, Meeting ChairmanThe Hebrew University of Jerusalem
GreetingsR. Haber, PresidentThe Israel Chemical Society
D. Patenkin, PresidentThe Hebrew University of Jerusalem
A. Nlr, PresidentIsrael Institute of Chemical Engineers
1. Shladov, ChairmanSociety of Chemical Industry Engineers n
Representatives of IUPAC and o5Overseas Chemical Societies
7lri*J)dfi Vp\3P33D *V'V OMlb .D
a>i?mn>a nnriyn rn3>pi2>3iNn
: jvo-a
n>n>D!3 n»tJMi\y*n m i n n
N>\D3 ,VPJO1I .1
1V3 ni>J3>D JTITUN1 I U P A C >3>S3
,n
10.40—11.15
OPENING LECTURE A A MfVJlS
Dedicated to the memory ofProfessor Ch. Weizmann
Chairperson : H. Levanon, Israel !?Ni\y> ,
Y. Ne'emanMinister of Science & Development nirponi y ion
TRIAL AND ERROR IN SCIENCE AND IN POLITICS
11.15—11.45
Coffee Break nap npvan
11.45—12.45
Auditorium W o m w D M
PLENARY LECTURE B
Chairperson: I. Dostrovsky, Israel im-iv!»
W.N. Llpscomb, Harvard University, USA
AESTHETICS OF SCIENCE
12.45—14.30
Lunch Break t)»in* itposn
nvyipio
.»
.» :
— 11 —
SCIENTIFIC PROGRAMהמדעיתהתוכנית
TUESDAV, APRIL 10 , 1984-תשמ"דניסוח'שכישי,יום
10.00-10.40
Audltorlum Wאודיסוויום
הפתיחהטקס
הכנסיו"רלנבון,ח.
בירושליםהעבריתהאוניברסיטת
OPENING CEREMONY
H. Levanon. Meeting Chairman Jniversity of Jerusalem זThe Hebrew
Greetings R. Haber. President The Israel Chemical Society
D. Patenkln, President The Hebrew University of Jerusalem
A. Nlr. President Israel Institute of Chemical Engineers
1. Shladov, Chairman Society of Chemical Industry Engineers
Representatives of IUPAC and Overseas Chemical Societ:es
:ברכותנשיאחוב.ו.
לכימיההישראליתהחברה
נשיאפסנקין,ד.
בירושליםהעבריתהאוניברסיטה
נשיאניו,א.
כימיתלהנדסההישראליתהאגודה
יו"רשלדוב,י.
תעשייתיתלכימיתהאינגיינריםאיגוד
בעולםכימייתיאגידית IUPACנציני
10.40-11.15
A OPENING LECTURE Aפתיחההרצאת
Dedicated to the memory ofשללזכרומוקדשת Profe88or Ch. Welzmannויצמןח.פוןפסוו
Chairperson : H. Levanon. Israelישראללבנון,ח. :ישוב-ראש
Y. Ne'emanגאמןי. Minister of Science & Developmentוהפיתוחהמדעשר
TRIAL AND ERRס R IN SCIENCE AND IN Pס LITICSומעשמדע
11.15-11.45
Coffee Breakקפההפסקת
11.45-12.45
Audltorlum Wאודיסוויום
B PLENARY LECTURE Bמליאההרצאת
Chairperson : 1. D08trov8ky. Israelישראלדוססוובסקי,י. :יושב-ראש
W.N. Llpscomb. Harvard University, USA
F SCIENCE סAESTHETICS
12.45-14.30
Lunch Breakצהוייםהפסקת
11 -
•
TUESDAY (cont'd)14.30—15.20
PARALLEL SESSIONSSprinzakRoom S-115 i i n
SESSION n T 1Chairperson: R.A. Moss, USA a"mN ,010 .« .i :
Z. Rappoport, The Hebrew University imnyn no>p-a>yiNn ,vn&iflt .*of Jerusalem n»!wn»:i
STABLE SIMPLE ENOLS
14.30—15.20
Room S-214 YTft
SESSION T2 T 2Chairperson: D. Meyerstein, Israel bN*w» ,I»'O«I>NO .1 :
Z. Dori, Technion — Israel Institute bN-ivy>i> >Jibi3DO iiao — p>3Don ,»wof Technology
METAL-METAL BONDING IN COORDINATION CHEMISTRY
14.30—15.20
Room S-117 l l f i
SESSION T3 T 3Chairperson : M. Cohen, Israel ^NIVP ,in3 .0 :
R. Pauncz, Technion — Israel Institute >ntm3O 1120 —of Technology
QUANTUM CHEMISTRY AND THE CHEMICAL BOND
14.30—15.20
Room S-29 t in
SESSION T4 T 4Dedicated to the memory of i>\y n a ^ n\y*tpioProfessor G. Stein 1»ov » -ncsnaSponsored by the Belfer Center n>n)Nn ipno!? naba o^)^ nit?nafor Energy ResearchChairperson: A. Heller, USA i"mN ,i n .x
J. Rabanl, The Hebrew University o»l?\y'n>3 n>iaiin no>tnn>yiNn ,»iai .»of Jerusalem
SOLAR PHOTOCHEMICAL CONVERSION : HYDROGEN GENERATION
14.30—15.20
Room S-217 *nn
SESSION T5 T 5Chairperson: A. Patchornlk, Israel bNi\y> , p n t v « M
A.H. Hassner, Bar-Han University ib'N~i2 nv?>p-a>riN ,upn .n .»<VINYL AZIDE, VERSATILE SYNTHONS
15.30—16.00
Coffee Break n»p
— 12 —
TUESDAY (cont'd ((חמשך)שלישילים14.30-15.20
PARALLEL SESSIONSמקבילותישיבות Sprlnzakשפרינצק
Room S-115חדר
T 1ישיבהארה"במוש,א.ר. :יושב-רא'ש
העבריתהאוניברסיטהרפופורס,צ.
בירושלים
SESSION T1 Chairperson: R.A. MOII, USA
Z. Rappoport, The Hebrew University em זof Jerusa
STABLE SIMPLE ENOLS
14.30-15.20
Room S-214חדר
T Zישיבהישראלמאירשסיין,ד. :יושב-ראש
לישראלטכנולוגימכון-הטכניוןדורי,צ.
IN COORDINATION CHEMISTRY
SESSION T2 Cha:rperson: D. Meyersteln. Israel
Z. Dorl, Technion - Israel Institute of Technology
METAL-METAL BONDING
14.30-"i5.20
Room S-117חדר
Tנישיבהישראלכהן,מ. :יושב-ראש
טכנולוגימכון-הטכניוןפאונץ,ר.
לישראל
SESSION T3 Chairperson: M. Cohen, Israel
R. Pauncz, Technion - Israel Institute of Technology
OUANTUM CHEMISTRY AND THE CHEMICAL BOND
14.30-15.20
Room S-29חדר
T 4ישיבהשללזכרומוקדשת
שסיין.גפרופשור
SESSION T4 Dedicated to the memory of Profellor G. Steln
Sponsored by the Belfer Centerהא(רגיהלמחקרבלפרמרכזבחסותfor Energy Research
Chairperson: A. Heוו er, USAארה"בחלר,א. :יושב-ראש J. Rabanl, The Hebrew Universityבירושליםהעבריתהאוניברסיטהרבני,י.
of Jerusalem SOLAR PHOTOCHEMICAL CONVERSION: HYDROGEN GENERATION
14.30-15.20
Room S-217חדר
T SESSION T5 5ישיבח Chairperson : A. Patchornlk, Israelישראלפציורניק,א. :יושב-ראש
A.H. Hallner, Bar·llan Universityבר-אילןאוניברסיטתהשנר,ח.א.VINYL AZIDE. VERSATILE SYNTHONS
115.30-18.00
" I קן"סקתCoff •• Br8CIk
12--
TUESDAY (cont'd)16.00—17.30
Foyers W + SPOSTER SESSION T
TA — SPECTROSCOPY n>£nptm\?p£)t> — TATB — SURFACE CHEMISTRY nOV/H TI")3>D — TBTC — PHOTOCHEMISTRY rP»rDl\7lfl — TCTD — ORGANIC SYNTHESIS J V i n i N m>n3">P — TDTE — ORGANIC REACTION n>a>Dl f P S p N n '31W3a — TE
MECHANISM D>35"I,1NTF — INORGANIC CHEMISTRY nv>mN~>N rPK)>D — TFTG — ANALYTICAL CHEMISTRY rPO>t?DN JVO'D — TG
16.00—17.30
Foyer W mtosN
WORKSHOP f> 3 t V
MICROCOMPUTERS IN CHEMISTRY TEACHING n>O>Dn JIN-Iinn D>l\yn)3'np>QInstructors: Z. Scherz, Israel t>N-i\y» ,\-\v A : D>n:a
Y. Wolman, Israel SHW , I » * N .»
17.45—18.45
Auditorium W
PLENARY LECTURE C C T\H^fS J1NJJ1T1
Chairperson : S. Alexander, Israel !?N-i\y> onjcsix .« : «ii<n«ii'J. Jortner, Tel-Aviv University n>3N-!7Ji no>o-i2'3iN ,"w\j">i» .»
CHEMISTRY OF SINGLE LARGE MOLECULES
19.30
Israel Museum *ta«» v**nin
RECEPTION, BUFFET DINNER )Wt3& VISIT OF THE ISRAEL MUSEUM
Sponsored by : : monn
Bank Hapoalim B.M. »"ya o^yifln pa
Municipality of Jerusalem o*bvn> n»vy
Faculty of Science, ,vaon tytnbi np>vn>nnbThe Hebrew University of Jerusalem t»*«nva nnsvn
Greetings:T. Kollek, the Mayor of Jerusalem o>b\yn> I I » T V VJJNT /p^ip •»A. Lifshitz, Head Institute of Chemistry r v a ^ TIDDH WNI * V S ^ .N
- 1 3 "
TUESDAY (cont'd ((חמשך)שלישייים16.00-17.30
Foyers W + Sאכסדרןת
POSTER SESSו T ON Tפוסטריםתצוגת
TA ספקטרוסקופיהSPECTROSCOPY TA TB השטחכימייתSTRY וSURFACE CHEM TB TC פוטוכימיהSTRY וPHOTOCHEM TC TD אורגניתסינתיזהC SYNTHESIS וORGAN TD TE בכימיהריאקציהמנגנוניORGANIC REACTION TE
MECHANISMאו,רגנית' Tf אי-אורגניתכימיהINORGArlllC CHEMISTRY TF
TG אנליטיתכימיהANAL YTICAL CHEMISTRY TG
16.00-17.30
Foyer Wאכסדרת
WORKSHOPדנהס
MICROCOMPUTERS IN CHEMISTRY TEACHINGהכימיהבהוראתמיקרומחשבים Instructors: Z. Scherz, Israelישראלשרץ,ו. :מנחים
Y. Woו man, Israelישראלןןלמו,י.
17.45-18.45
Audltorlum Wאןדיסןריןם
C PLENARY LECTURE Cמליאההרצאת
Chairparson: S. Aו exander, Israelישראלאלכסנדר,ש. :יושב-ראש J. Jortner, Tel-Aviv Universityתל-אביבאוניברסיטתיןרסנר,י.
CHEMISTRY OF SINGLE LARGE MOLECULES
מזנוןארוחתקבלת-פנים,ישראלבמוזיאוןוביקור
19.30
ו sraeו Museumישראלמןזיאון
NNER וON, BUFFET D וRECEPT SRAEL MUSEUM וT OF THE וVIS &
: Sponsored by
• Bank Hapoallm B.M
Munlclpallty of Jerusalem
, Faculty of Sclence The Hebrew Unlverllty of Jerusalem
:בחסות
בע"מהפןעליםנבק
ירןשליםעיריית
הסבע,ןלמדעילמתימסיקהה.קןלסה
בירןשליםהעבריתהאונירבסיסה
:ברכותירושליםעירייתראשקלוק,ס.
לכימיההמכוןראשיץ, Wלי'א.
Greetings: T. Kollek, the Mayor of Jerusalsm A. Llflhltz, Head Institute of Chemistry
-13 -
_ ...• -.- --":.--..;.,,-1. _____ · ________ · __
.. .
--j ,-'
·;t,
j
, J,t
ז.
WEDNESDAY, APRIL 11, 1984 — T'ttVfl )V>i 'O ,>y>31 t»>
08.30—09.30
Auditorium W m»*»o>7iKPLENARY LECTURE D D f l *O*»Dedicated to the memory of b\y "nDrt nvnpioProfessor L. Farkas vpiaChairperson : A. Ben-Reuven, Israel ^tcw , iawna •*<
R.D. Levine, The Hebrew University nnayn no'tna^JiNn ,\*ft . i ••>of Jerusalem o>!?\yn>:i
SYMMETRY AND CHAOS
09.30—10.30Auditorium W
PLENARY LECTURE E E flN'bttChairperson : S. Sarel, Israel t>N-i\y> ,^NIW .O
J.M. Lehn, Universite Louis Pasteurde Strasbourg, France
SUPRAMOLECULAR CHEMISTRY — CHEMISTRY EEYOND THE MOLECULE
10.30—11.00
Coffee Break nap
11.00—12.30
Room S-28 i*tnSYMPOSIUM A A
Chairperson: N. Ber.-Zvi, Israel N-»\y» ,'3J(-ia d
SELECTED PROBLEMS IN rvoon nNiini nnnnaCHEMICAL EDUCATION
Panel Members: : )vt mutHigh School Teachers O"31D'TI -I3O->TI33 D">-»IQ
Ministry of Education Officials Trnnn *nvyao DvppaUniversity Teachers niNO'ona'JiNo o»i<ioIndustrial Chemists n»\yynna O>NQ>D
— 14 —
. . WEDNESDAY, APRIL 11 , 1984-תשמ"דניסוט'רביעי,יים08.30-09.30
AudJtorJum Wאודיטוריום Dמליאההרצאתשללזכרומוקדשת
פרקשל.פרופסור
ישראלבן-ראוןב,א. :יושב-ראש
העבריתהאוניברסיטהלוין,ד.ר.
בירושלים
PLENARY LECTURE D Dedicated to the memory of Professor L. Farkas
Chairperson: A. Ben-Reuven, Israel
R.D. Levine, The Hebrew Univers:ty of Jerusalem
SYf\,~METRY AND CHAOS
09.30-10.30
Audftorfum Wאדויטוריום Eמליאההרצאתישראלשראל,ש. :יושב-ראש
PLENARY LECTURE E
Chairperson: S. Sarel, Israel
J.M. Lehn, Universite Louis Pasteur de Strasbourg, France
SUPRAMOLECULAR CHEMISTRY - CHEMISTRY 8EYOND THE MOLECUl.E
10.30-11.00
Coffee Breakקפההפסקת
11.00-12.30
Room S-28חדר Aרב-שיח
ישראלבן-צבי,ב. :יושבת-ראש
הכימיהבהוראתנבחרותבעיות
:דיוןצוותתיכונייםבבתי-ספרמורים
החינוךמנושרדפקידים
מאוניברסיטאותמרצים
מהתעשייהכימאים
SYMPOSIUM A
Chairperson: N. Ben-Zvl, Israel
SELECTED PROBLEMS IN CHEMICAL EDUCATION
Panel Members: High School Teachers Ministry of Education Officials University Teachers Industrial Chemists
-14 -
- --'-"-----
WEDNESDAY (cont'd) Cjvan) >V»ai tn>11.00—11.50
PARALLEL SESSIONSSprlnzak
Room S-115 vtn
SESSION wi w 1Dedicated to the memory of !?\y Tort nvytpinProfessor E.D. Bergmann ions .7 .N
Chairperson : M. Cais, Israel !wi\y> ,o»wp .»
J. Klein, The Hebrew University nnayn rto>o-a>3iNn ,v»*P •*of Jerusalem D>b\yn>n
STABILIZATION BY CHARGE AND DONOR — ACCEPTOR ALTERNATION :AN EFFECT REVEALED BY POLYMETALATION
11.00—11.50
Room S-117 YTnSESSION W2Dedicated to the memory ofProfessor G.M.J. Schmidt
Chairperson: S.M. Sprecher, Israel
M. Lahav, The Weizmann Institute of Science
SOLID STATE ORGANIC
11.00—11.50
CHEMISTRY
Room S-214 n n
SESSION W3
Chairperson: J. Feitelson, Israel
H. Elsenberg, The Weizmann Instituteof Science
MACROMOLECULES ARE THE
ynot? iou>i Ton
STUFF OF LIFE
WO n\yipm
DO
w
: \yNTi\yi>
3 m*v^
: \yNvnw>
a«>N .n
11.00—11.50
Room S-217 rrn
SESSION W4 w4
Chairperson : A. Lifshitz, Israel bNi\y> ,vt>fl»* •»<
R.H. Schuler, University of Notre Dame, USA
OPTICAL ABSORPTION, ESR AND RAMAN SPECTROSCOPY OFCHEMICAL INTERMEDIATES
12.30—14.00
Lunch Break a»in*
— 15 —
WEDNESDAY (cont'd ((המשך)רביעייום11.00-11.50
PARALLEL SESSו ONSמקבילותישיבות Sprlnzakשפרינבlק Room S-115חדר
•
W 1ישיבהשללזכרומוקדשת
ברגמןד.א.פרןפסןר
ישראלקאיס,מ. :יושב-ראש
העבריתהאוניברסיטהקליין,י.
בירושלים
ON W1 וSESS Dedicated to the memory of Professor E.D. Bergmann
Chairperson: M. Cais, Israel
eln, The Hebrew University וJ. K of Jerusalem
STABILIZATION BY CHARGE AND DONOR - ACCEPTOR ALTERNATION: AN EFFECT REVEALED BY POLYMETALATION
11.00-11.50
Room S • 117 'חדר w Zישיבהשללזכרומוקדשת
שמידסג.מ.י.פרןפסןר
ON W2 וSESS Dedicated to the memory of Professor G.M.J. Schmldt
Chairperson: S.M. Sprecher, Israelישראלשפרכר,מ.ש. :יושב-ראש
M. Lahav, The We:zmann Institute of Scienceלמדעויצמימכוילה,במ.
SOLID STATE ORGANIC CHEMISTRY
11.00-11.50
Room S-214חדר
w SESSION W3נינזיבה
ישראלפייסלסןן,י. :יושב-ראש
למדעויצמומכוןאיזנבר,גה.
Chairperson: J. Feltelson, Israel
H. Elsenberg, The Weizmann Institute of Science
MACROMOLECULES ARE THE STUFF OF LIFE
11.00-11.50
Room S-217חדר
SESSו W4 ON W4ישיבה
Chairperson : A. Llfshltz, Israelישראלליפשיץ,א. :יושב-ראש
R.H. Schuler, University of Notre Dame. USA
OPTICAL ABSORPTION. ESR AND RAMAN SPECTROSCOPY OF CHEMICAL INTERMEDIATES
J'
12.30-14.00
Lunch Breakצהרייםה'סקת
-15 -
WEDNESDAY (cont'd) <7v»n) >V>ai O1>14.00—14.50
PARALLEL SESSIONSSprinzak —Room S-214 Ytn
SESSION W5 W5
Chairperson: M. Goldstein, USA n"mN , v w i b i J .» :
C. Lifshitz, The Hebrew University nnnyn no>tn:i>yiNnof Jerusalem
IONS AND LIGHT: FROM THE ORIGIN OF LIFE TO BIOMEDICAL APPLICATIONS
14.00—14.50
Room S-115 Ytn
SESSION w 6 w 6
Chairperson : B. Fuchs, Israel !?N-i\y> ,cpifl .a
A. Shani, Ben-Gurion University of an i m i r p nu>oi3'3">Nthe Negev
THE ROLE OF PHEROMONES — INTEGRATED PEST CONTROL
14.00—14.50
Room S-117 Ytn
SESSION W 7 W 7
Chairperson: J.A. Epstein, Israel i?Nn>y> ,)*OW>N .» .» :
2. Zurr, Koor Chemicals Ltd. o"vn n>n>D HD ,HX .S
ISRAEL'S CHEMICAL INDUSTRY — CENTENNIAL (OF WHICH ONLY HALF IS HISTORY)
14.00—14.50
Room S-217 Ytn
SESSION W 8 W 8 Ttt'V*
Chairperson : Y. Manassen, Israel "yniv* ,iwo .» :
E. Gileadi, Tel-Aviv University nnN-^n jiD>tn:i>nN ,»*tv J .
ELECTROLYTIC CONDUCTION MECHANISMS IN NON-POLAR SOLVENTS
15.00—15.30
Coffee Break
— 16 —
WEDNESDAY (cont'd ((המשך)רביעייים14.00-14.50
PARALLEL SESSIONSמקבילותישיבות Sprlnzak-ויםרינצק Room S-214חדר
W SESSION W5 5ישיבה
העבריתהאוניברסיטהליפוייץ,ח.
בירושלים
Chairperson: M. Goldsteln, USA
C. Llfshitz, The Hebrew Univarsity of Jerusalem
ארה"בלדשטיין, iגמ. :יישב-ראש
NS סMEDICAL APPLICATI סBI סF LIFE T סRIGIN סM THE סNS AND LIGHT: FR סI
14.00-14.50
Room S-115חדר
W SESSION W6 6ישיבה
Chairperson : B. Fuchs, Israelישראלפוקס,ב. :יושב-ראש
A. Shanl, Ben-Gurion University ofבנגבבן-גוריוןברסיטתאיניויגי,א.the Negev
L סNTR סNES - INTEGRATED PEST C סM סF PHER סLE סTHE R
14.00-14.50
Room S-117חדר
w SESSION W7ןישיבה
בע"מכימיהכורצור,צ.
Chairperson : J.A. Epsteln, Israel
Z. Zurr, Koor Chemicals Ltd.
ישראלאפויטין,א.י. :יושב-ראש
) NL Y HALF IS HISTORY סF WHICH (סISRAEL'S CHEMICAL INDUSTRY - CENTENNIAL
14.00-14.50
Room S-217חדר
W SESSION W8 8ישיבה
ישראלמגסו,י. :יושב-ר'אש
תל-אביבאוניברסיטתגלעדי,א.
Chairperson: Y. Manassen, Isra91
E. Glleadl, Tel-Aviv University
LVENTS סLAR S סN-P סN MECHANISMS IN N סELECTROLYTIC CONDUCTI
15.00-15.30
Coffee Br.akקפההפסקת
-16 -
~=_ .. _ ... ----
POSTER
WH —
Wl —
WJ —
WK —
WL —
WM —
WN —
WO —
WEDNESDAY (cont'd) (*rv15.30—17.30
Foyers W + S a m i
SESSION W
ELECTROCHEMISTRY
THEORETICAL CHEMISTRY
PHYSICAL CHEMISTRY
BIO-ORGANIC CHEMISTRY
PHYSICAL ORGANIC CHEMISTRY
POLYMERS
INDUSTRIAL CHEMISTRY
CHEMICAL EDUCATION
15.30—17.30
Foyer W JITTO
n>K)>D1"IV7p!7N —
n>\mN>n n>»>3 —Jl>t?p>P>3 n>O>D —
n>bp>D>3 n > j m N JT>O>D —
ji>Ti»\yvn n>o>D _n>D>Dn TiKTin _
9K
WH
Wl
WJ
WK
WL
WM
WN
WO
WORKSHOP (confd)
MICROCOMPUTERS IN CHEMISTRY TEACHING TVO'DD JlNTin:i
17.30—18.30
Auditorium W OVWJVPNPLENARY LECTURE F F r)N»bO
Chairperson: D. Lavie, Israel t»N-i\y> ,N» I * .T
D. Ginsburg, Technion — bNiwb >si i33o IIDD — ypwunIsrael Institute of Technology
CHEMICAL ARCHITECTURE : PROPELLANES AS MODELS FORCLARIFICATION OF STEREOCHEMICAL PROBLEMS
19.30
Binyanel Ha'ooma — naiNnPlncus Hall —
GALA DINNER siwanSponsored by :
Israel Chemical Industries Ltd. o"ya
Chairperson : H. Levanon, Israel bNi\y> ,
Greetings:His Excellency the President of Israel rwton towCh. Herzog aiann .n
After-Dinner Lecture : : "nrmNn >inN,,E. Katchalskl-Katzlr, ynn!? <|n^>i IIDO
The Weizmann Institute of Science n>ai>rtj»& Tel-Aviv University
50 YEARS OF CHEMICAL RESEARCH IN ISRAEL : ACHIEVEMENTS AND CHALLENGES
— 17 •—
WEDNESDAY (cont'd ((המשך)רביעייים15.30-17.30
Foyers W + Sאכסדרות wפןסטריםתצןגת
WH אלקטרוכימיה
ON W וPOSTER SESS
ELECTROCHEMI'STRY WH
Wו THEORETICAL CHEMISTRYתיאורטיתכימיה Wו
WJ פיסיקליתכימיהPHYSICAL CHEMISTRY WJ
WK ביו-אורגניתכימיהBIO-ORGANIC CHEMISTRY WK
WL פיסיקליתאורגניתכימיהPHYSICAL ORGANIC CHEMISTRY WL
WM פולימריםPOLYMERS WM
WN תעשייתיתכימיהINDUSTRIAL CHEMISTRY WN
WO הכימיההוראתCHEMICAL EDUCATION WO
15.30-17.30
Foyer Wאבסדרת WORKSHOP (cont'd {(המשך)דגהס
MICROCOMPUTERS IN CHEMISTRY TEACHINGהכימיהבהוראתמיקרומחשבים
17.30-18.30
Auditorlum Wאודיסוריום F PLENARY LECTURE Fמליאההרצאת
Chairperson: D. Lavie, Israelישראלליבא,ד. :יושב-ראש
D. Ginsburg, Technion-לישראלסכנולוגימכון-הסכניוןד.גינצבור,גIsrael Institute of Technology
CHEMICAL ARCHITECTURE: PROPELLANES AS MODELS FOR CLARIFICATION OF STEREOCHEMICAL PROBLEMS
19.30
Blnyanel Ha'oomaהאומהנבייני Plncus Hall-פינקו."אולם
GALA DINNERחגיגיתארןחת-ערב
: Sponsored by • ndustrles Ltd וChemlcal וsrae ו
Chairperson: H. Levanon, Israel
: Greetings His Excellency the President of Israel Ch. Herzog
: After-Dinner Lecture , E. KatchaI8kl-Katzlr
The Weizmann Institute of Science Tel·Aviv University &
50 YEARS OF CHEMICAL RESEARCH
:בחסותבע"מלי.ראלכיסיקלים
ישראללנבוו, • n :יושב-ראש
:ברכותהמדינהנשיאכבדו
n • הרצוג
:הארוחה""אחריהרצאתלמדעויצמןמכוןקצל'קסיק-ציר,א.
ת'"לאביבואוניברסיסת
IN ISRAEL: ACHIEVEMENTS AND CHALLENGES
-17-
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I
THURSDAY, APRIL 12, 1984 — T'ttVJl
08.30—09.30Auditorium W
PLENARY LECTURE G G
Chairperson: F.Bergmann, Israel
H.C. Brown, Perdue University, USA
THE BORANE ADVENTURE — PAST, PRESENT AND FUTURE
09.30—10.30
Auditorium W
PLENARY LECTURE H H
Chairperson: O. Kedem, Israel lwi\y> ,oip .H : vyirrnavyp
R. Parlser, E.I. du Pont de nemours & Company, USA
NEW ORIENTATION FOR POLYMER SCIENCE AND TECHNOLOGY
10.30—11.00
Coffee Break nsp npoon
11.00—13.00
Auditorium W omwvmc
SYMPOSIUM B B
Chairperson : M. Ottolenghi, Israel !?Ni\y> ,»H*IOIN .» :
SCIENCE, INDUSTRY AND SOCIETY mini
Panel Members:
M. Avron, The Weizmann Institute of Science yvnb ynw yon ,ina« .a
P. Zusman, The Hebrew University
of Jerusalem
B. Peled, Elbit Computers Ltd.
Z. Rotem, U.S.-lsrael Binational jnot? jvaiN^mn ppn
Science Foundation
M. Reis, Israel Chemical Industries Ltd.
G. Czapski, The Hebrew University nnaynof Jerusalem
E. Sharon, Ministry of Finance -ISINH n«in ,\\y» .y
13.00—14.30
Lunch Break a»inx npvan
— 18 —
. . THURSDAY, APRIL 12 , 1984-תשמ"דניסויוחמישי,יים08.30-09.30
Audltorlum Wאדויטוריום
G PLENARY LECTURE Gמליאההרצאת
Chairperson: F.Bergmann, Israelישראלברגמן,פ. :יושב-ראש
H.C. Brown, Pardue University. USA
THE BORANE ADVENTURE - PAST. PRESENT AND FUTURE
09.30-10.30
Audltorlum Wאודיטוריום
H PLENARY LECTURE Hמליאההרצאת
Chairperson: O. Kedem, Israel ישראלקדם,א. :יושבת-ראש
R. Parlser, E.I. du Pont de nemours & Company. USA
NEW ORIENTATION FOR POLYMER SCIENCE AND TECHNOLOGY
)Q.10.30-11ן
Coffee Breakקפההפסקת
ן"11.00-13.00
Audltorium Wאודיטוריום
Bרב-שיח
יחברהתעשייהמדע,
SYMPOSIUM B
Chairperson: M. Ottolenghi, Israel
SCIENCE. INDUSTRY AND SOCIETY
Panel Members:
M. Avron, The Weizmann Institute of Science
P. Zusman, The Hebrew University of Jerusalem
B. Peled, Elbit Computers Ltd.
Z. Rotem, U.S.-Israel Binational Science Foundation
M. Rels, Israel ChemicaJ Jndustries Ltd.
G. C~apskl, The Hebrew University of Jerusalem
E. Sharon. Minlstry of Finance
ישראלטולנגי. iאמ. :יושב-ראש
:דייןציית
למדעויצמימכויאברון,מ.
העבריתהאוניברסיטהזוסמן,פ.
ביררשלים
בע"ממחשביםאלביטפלד,Oב
למדעהדו-לאומיתהקרירותם,ז.
ארה"ב-ישראל
בע"מלישראלכימיקליםרייס,מ.
העבריתהאוניברסיטהשפסקי,.ג
ביררשלים
האוצרמשרדשרון,ע.
13.00-14 .~פ
Lunch Breakצהרייםהפסקת
- 18-
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THURSDAY (cont'd) (7w»n) > V » n OV14.30—15.30
Auditorium W O I ' I W H N
PLENARY LECTURE I I 7iN»b»
Chairperson : A. Loewenstein, Israel i>N-i\y> ,i»oto»ib .N :
Z. Luz, The Weizmann Institute ynxft "|»is>i lionof Science
CHEMISTRY WITH LIQUID CRYSTALS
15.30—16.00
Coffee Break nflp npvan
16.00—17.00
Auditorium W
PLENARY LECTURE J J 7!N'b»
Dedicated to the memory of b»vy nDrt ji\ytpioProfessor Aharon Katzlr-Katchalsky >pt>yap-vsp
Chairperson: E. Katchalski-Katzir, Israel bNt\y> ,i»»M. Eigen, Gottingen, F.R. Germany
EVOLUTIONARY CHEMICAL TECHNOLOGY
17.00—17.30
Auditorium W
CLOSING SESSION T)!»>»
Chairperson: R. Haber, Israel !wi\y> ,ian .1 :
AWARD GIVING CEREMONY OF THE ISRAEL CHEMICAL SOCIETY MEDAL
vpv
— 19 —
THURSDAV (cont'd ((המשך)חמישייים14.30-15.30
Audltorlum Wאודיסוריום
PLENARY LECTURE I 1מליאההרצאת
ישראללוינשסיין,א. :יושב-ראש
למדעויצמומכןולזו,ו.
Chairperson: A. Loewenlteln, Israel
Z. Luz, The Weizmann Inst:tute of Science
CHEMISTRY WITH LIQUID CRYSTALS
15.30-16.00
Coffee Breakקפחחפסקת
16.00-17.00
Audltorlum Wאודיסוריום
Jמליאההרצאתשללזכרומיקדשת
קציר-קצילסקיאחרוןפרופסור
ישראלקצילסקי-קציר,א. :יושב-ראש
PLENARY LECTURE J
Dedicated to the memory of Profellor Aharon Katzlr-Katchallky
Chairperson: E. Katchallkl-Katzlr. Israel M. Elgen. Gottingen, F.R. Germany
EVOLUTIONARY CHEMICAL TECHNOLOGY
17.00-17.30
Audltorlum W"ודיסוריום
CLOSING SESSIONנעילהישיבת
Chairperson: R. Haber. Israelישראלחבר,ר. :יושב-ראש
AWARD GIVING CEREMONY OF THE ISRAEL CHEMICAL SOCIETY MEDJ.\L
לכימיהראלית Iהישהחברהמדלייתהענקתסקס
בכימיהמצסיינותעבודותעלתיכונייםבתי-ספרלתלמידיפרסיםחלוקת
-19 -
.. .,
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wan mpn.avnyaa ,a>bvyiva nnayn'i-^i t»i ovnonwa io«pn>
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on p\y .njmnn >t»oia JIN am> nNwiJi own an TIN foyi> o>\ypano
.17.30 iy 16.00 nyvwo , >"iaNa' 10 ,'v>^vy ova D>'pnn T o>-i\3oian nnun .1
.17.30 ly 15.30 nyvya ,^noNa 11 ,»y>an ova D»pnn W o>iouian niiiin .2
oo\y i>ii*> vbyw m!?n 'arby on!?\y -ivjpian TIN ppnn!? o>\ypann
pna INHV novnn
naoyo i?ap> innwn i?Di ,n? b3i> P33 naatf nNmn mni>a INIT nonin10 ,>\y» \y m>a invo I N H p n D>ann\yon Tni>w^ nna>
nnmn TIN
o»annvyon m*i»«»!7 nnwa n»nn (n^nron) ionw i»jaa\y nnuapn: nwan niywa
11.00 iy 07.30-Q ipia15.00 iy 12.45-n o»-inii19.00 iy 16.00~o any nmiN
iim 5 T n m nvyjna nNbo mnnsmrrnN iaba won >annv>nb nyijio 73 byp n a I*IDQ> o>ini>n D>\yil?n .(D>!?p\ya
.(02) 660192 : yiabo .01 nyaj D>b\uiva nnayn n\3>oia>3iNn ,n^ba n>a
.(02) 882244 : yinfrv .a>aiiin i n ,o>b>\yTi>a n>iayn no>pna>3iNn ,<pntn>N» w"y bw
.(02) 528221 : yiabu .o»t?vnn> ,2 yiuayn a i m ,n\?P3iP
— 20 —
בככימידע
חבנסמקום
גבעת-רם.בירושלים,העבריתהאוניברסישה
שפרינצק.וב:נייןוייזבאודישוריוםיתקיימוההרצאות
ומודיעיןהרשמחדובן
:הבאותבשעותהמשתתפיםלשירותפתוחויהיהוייזבבנייןימוקםוהמודיעיןההרשמהדוכן
19.00עד-16.00מבאפריל 9שנייום 18.45עד-08.30מ 18.30עד-08.00מ 17.30עד-08.00מ
באפריל 10 ,שלישייום
באפריל 11רביעי,יום
אבפריל 12חמישי,יום
תגים
יתבקשוהםשכןההזמנה,כרשיסיאתעמםולשאתהשםתגאתלענודמתבקשיםהמשתתפים
ולאירועים.להרצאותבכניסהלהציגם
פו.סטריםתצוגות
• 17.30עד 16.00משעה,באפריל, 10שלישי,ביוםתתקיים Tהפוסשריםתצוגת . 1
. 17.30עד 15.30משעהבאפריל, 11רביעי,ביוםתתקיים Wהפוסשריםתצוגת . 2
ומספרם.שמםיצויןשעליוהלוחעל-גבישלהםהפוסשראתלהתקיןמתבקשיםהמציגים
המודיעין.לדוכןלפנותנאמשרדיוציודבירוריםבדבר
השתתפותאישור
המודיעין.בדוכןיוצאוהרשמהדמיששילמולמיהשתתפותאישורי
מיוחדתדוארחותמת
לכדבנוסףמוחתמת.מעשפהיקבלמשתתףוכלזה,יובלכנסלכבודהוצאהמיוחדתדוארחותמת
דוארrןברילמשלוחוייז,בבנייןבאפריל, 10שלישי,ביוםמיוחדדוארדוכןהמשתתפיםלשירותיפתח
הכנס.חותמתאתשישאו
ארוחות
מחירון)לפיעצמי(שירותהמשתתפיםלשירותפתוחהתהיה(המינהלה)שרמןשבבנייןהקפשריה
:הבאותבשעות 11.00עד-07.30מבוקרארוחת 15.00עד-12.45מצהרייםארוחת 19.00עד 16.00נז·ערבארוחת
לאדםדולר 5במחירבהגשהמלאהארוחת-צהרייםבלבדהכנסלמשתתפימוצעתכדעלבנוסף
אותםלרכושמת'בקשיםוהמשתתפיםהמודיע~ן,בדוכןימכרומיוחדיםתלושיםשנקלים).(התשלום
וצפיפות.עיכוביםלמנועכדימראש
מלונות
.) 02 ( 660192 :שלפוןרם.גבעתבירושליםהעבריתהאוניברסישהבלגיה,בית
.) 02 ( 882244 :טלפווהצופים.הרבירושלים,העבריתהאוניברסישהמאירסדורף,ע"שהסנלבית
.) 02 ( 528221 :שלפוןירושליס. , 2וולפסוןרחרבסונסטה,מלון
- 20-
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nt7>33n oy ruotn o»oi3 smnb
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בערב,שלישיביוםובחזרהישראלמוזיאוןאלבגבעת-רםהקמפוסשלהראשימהשעריצאואוסובוסים
בערב.רביעיביוםהחזרה)(ללאהאומהבנייניואל
ישראלבמוזיאוןוארוחהקלבת-פנים
המוזיאוןאלהראשימהשערהסעה
העירראשעל-ידיקבלת-פנים
מזנוןארוחת
במוזיאוןקצרביקור
המרכזיתולתחנההאוניברסיסהשלהראשילשערחזרההסעה
לארוחה.הכניסהעםהזמנהכרסיסלהציגנא
חגיגיתארוחת-ערב
האומהבנייניאלהראשימהשערהסעה
פינקוסבאולםחגיגיתארוחת-ערב
לארוחה.הכניסהעםהזמנהכרסיסלהציגנא
המודיעיו.בדוכןמראשלרכושישלנילוויםכרסיtיים
ודוארבנקשירותי
הראשי.לשערבסמוךנמצאאוסומסיבנקשירות
שרמן.בבנייןנמצאיםודוארבנקסניף
ציבורייםטלפונים
אפשראסימוניםהמרתף.בקומתלקפסריה,הכניסהלידשרמן,בבנייןממוקמיםציבורייםסלפונים
המודיעין.בדוכןלרכוש
ינהל
-בע"מטורסקופלכחברתלפנותנא-וכדומהבירוריםהזמנות,-בירושליםללינההקשורבכלהמודיעין.דוכןכמישעותבאותןהמשתתפיםלשירותפתוחויהיהוייזבבנייןנמצאהדוכןקונגרסים.
המארנגתהוועדה
:הכנסלאחרהיו"רכתובתלנבוןחייםפרופי
פיסיקליתלכימיההמחלקה
בירושליםהעבריתברסיסההאוני
91904ירושליםגבעת-רם, . 02-585544 :סלפון
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:הנסיעותוסובנותהמארנגתהחברהקונגרסים-בע"מטווסקופל
21סשרניחובסקירחוב 4413ת"ד
61 044תל-אביב • 03-653616 :טלפון
- 21
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GENERAL INFORMATION
MEETING VENUEThe Givat Ram Campus of the Hebrew University of Jerusalem. Sessions will be heldat the Wise Auditorium and the Sprinzak Building.
REGISTRATION & INFORMATIONThe Registration & Information Desk will be located at the Wise Building and openas follows :Monday, April 9 16.00 to 19.00 hrs.
Tuesday, April 10 08.30 to 18.45 hrs.
Wednesday, April 11 08.00 to 18.30 hrs.
Thursday, April 12 08.00 to 17.30 hrs.
NAME TAGPlease wear your name tag at all sessions and social events.
POSTER SESSIONS1. Poster Session T will be held on Tuesday, April 10, from 16.00 to 17.30 hours.2. Poster Session W will be held on Wednesday, April 11, from 15.30 to 17.30 hours.Presenters are requested to post their posters on the panel marked with their nameand poster number. Assistance and stationery will be provided at the Information Desk.
TRANSFERSTransfers will be provided from the Campus main gate to the Israel Museum (bothdirections) on Tuesday evening, and to Binyanei-Ha'ooma {Israel's Convention Centre)on Wednesday evening (one way only).
RECEPTION & DINNER•— Transfer from the Campus main gate to the Museum— Reception by the Mayor of Jerusalem— Buffet Dinner at the Museum— Short tour of the Israel Museum— Return transfer to the Campus main Gate and central bus station
GALA DINNER— Transfer from the Campus main gate to Binyanei-Ha'ooma
(Israel's Convention Centre)— Gala Dinner at the Pincus Hall— Tickets for accompanying persons available at the Information Desk.
SPECIAL CANCELLATIONA special cancellation has been issued to commemorate this Anniversary Meeting.A special postal service will function on Tuesday, April 10, at the Wise Building,and outgoing mail will be stamped with this special Cancellation. Envelopes will beavailable at the Information Desk.
CERTIFICATE OF ATTENDANCECertificate of Attendance can be obtained from the Information Desk.
— 22 —
MEALSMeals are available at the self-service cafeteria at the Sherman Building as follows:
Breakfast 07.30 to 11.00 hrs.
Lunch 12.45 to 15.00 hrs.
Supper 16.00 to 19.00 hrs.
In addition, a 3-dish special lunch is offered to the participants of ths Meeting atUS$5 per person. Please obtain vouchers in advance from the Information Desk.
BANK /POST OFFICEThere is a bank branch and a post office at the Sherman Building.
For opening hours please check at the Information Desk.
PUBLIC TELEPHONESPublic telephones are located at the Sherman Building (lower ground).
Tokens can be purchased at the Information Desk.
HOTELSBelgium House, The Hebrew University of Jerusalem, Givat Ram Campus.Phone: (02)660192.
The Maiersdorf Faculty Club, The Hebrew University of Jerusalem, Mt. Scopus Campus.Phone: (02)882244.
Sonesta Hotel, 2 Wolfson Street. Phone: (02)528221.
TRAVEL & ACCOMMODATION DESKKOPEL TOURS Ltd. — CONVENTIONS, the official travel agents for the Meeting, willoperate the Travel & Accommodation Desk at the Wise Building during the samehours of the Information Desk.
Participants are invited to make any queries and additional reservations they maywish to.
ORGANIZING COMMITTEEAddress of the Chairman after the Meeting :
Prof. Halm LevanonDept. of Physical ChemistryThe Hebrew University of JerusalemGivat-Ram, 91 904 Jerusalem, Israel.(Telephone: (02) 585544).
ORGANIZERS & TRAVEL AGENTSKOPEL TOURS Ltd. — CONVENTIONSP.O.Box 4 4 1 361 044 Tel-Aviv, IsraelTelephone: (03)653616Telex : 35562 Ktor ILCable: Kopel TelAviv
— 23 —
ABSTRACTS
INVITED
POSTER
POSTER
LECTURES
SESSION
SESSION
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INVITEDLECTURES n n n n n
INVITED LECTURES T1 — T5 9»3»T1tt
TUESDAY, APRIL 10 "|U>3 «n ,>\y>!7\y OV
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STABLE SIMPLE EH0L5
Z . RAPPOPORT
Department of Organic Chemistry, The Hebrew Universi ty, Jerusalem , Israel
Simple enols, i . e . , those substituted only with hydronen, alkyl or aryl groups
are usually regarded as unstable short - l ived species. This is not Generally
true. S ter ica l l y hindered 2,2-diarylethenols ( e . g . , 1_), 2 ,2 -d i a r y l - l - a l ky l -
ethenols (e .g . , 2) and 1,2,2-tr iarylethenols (e .g . , 3_-9) are frequently
therrnodynariically and k ine t i ca l l y stable species.
Mes2C=C(OH)R Ar(Mes)C=C(OH)Mes l les^ I!
1 R = H 3 Ar = Ph Mes'^O2. R = t-Bu £ Ar = 4-t-Bu,2,6-Me2C6H2 H x
_3 k = Pii " 12
4 R - 2,4-Me2CGH4
5 R = Hes Mes = Mesityl = ^C=C
6_ R = O-Anthryl 2,4,6-Me3CgH2
I R - 2,4,6-He3,3-He0Ci5H —
Some of the i r properties which were studied by us are summarized below: (a) The
enol «=^*ketone equ i l ib r ia for t r iary lethenols depend on the bulk of the aryl
substituents : Ke follows tiie order b_, 6_ •> 4_ ^ 3_. In hexane, j _ , _5, G and 3 are
wore stable than the i r isoneric ketones. (b) l'e for the aldehyde derivative X >
Ke for the ketone derivat ive 3_. (c) Triarylethenols have a chira l propeller con-
formation in the so l id state and probably also in solut ion, (d) The threshold
iiiechanisi.i for enantiomerization of these vinyl propellers depends on the bulk of
the substi tuents. I t is a 3-rinr; f l i p for b_ and 6_, a 2-ring f l i p for 2_ and a 1-
r ing f l i p fo r J_. (e) The conformation of the OH aroup is syn (_1T) in non-polar
aprotic solvents (e .g , CC14), but the percentage of a second, probably an an t i -
c l ina l conformation JJ_ in hydrogen bond accepting solvents increases on increas-
ing the solvent hydrogen bonding accepting a b i l i t y and i t is the exclusive con-
formation in DHSO. ( f ) Only the Z-enol 8 could be prepared, whereas an E *=^ Z
isomerization of the enol £ takes place in so lut ion, (g) Diastereomeric enols
derived from 7. are observed by NMR. (h) Enols _3 and 3 give i n i t i a l l y d i f ferent
ion radical species than the i r isomeric ketones in the qas phase.
i
T2
TRANSITION METAL COMPLEXES WITH METAL-METAL BONDS
Z. DORI
Department of Chemistry, Technion - Israel Institute of Technology,Haifa 32000, Israel.
The chemistry of transition metal compounds containing mete"!-net;:!
bounds has lately bnco'no m e of th? most activp in inorganic
cheristry. Thf-3.? cornf.oi-rtis havi* r.:;'.. ificancc in nany directions,
including catalysis and solid state science. Most of these compounds
are formed by metal atoms in low formal oxidation states involving
primarily second and third row transition elements. Bond order of 1 to
4 between metal atoms are now well extablished with short M-M
distances for the multiply bonded compounds.
The reactivity of M-M bonds offered interesting new chomstry. A
metal-metal multiple bond can be a site of reactivity for an inorganic
compound in the same way as multiple C-C or C-N bonds provide reactive
functionalities in organic chemisty.
In this lecture I should like to trace the development of the field
and emphasize some of the more important structural and chemical
aspects of this class of unusual compounds.
32
T3
QUANTUM CHEMISTRY AND THE THEORY CF THE CHEMICAL BOND
Ruben PaunczDepartment of Chemistry, Techion, Israel Institute of Technology, Haifa, Israel
Quantum chemistry provides the theoretical background for th? interpretation of
the chemical bond. Soon after the discovery of quantum mechanics, iieitler and
London showed how one can understand the formation of the simplest molecule
(H^). Ir this an.i in tnn subsequent calculations one uses the liorn-Cppenheimer
approximation and obtains a potential energy curve (surface for polyatomic iiiole-
ci.U'S). The minirr.a on the potential energy surface provide the equilibrium bond
lengths and bond CIT'^S of stable molecular species; the saddle points relate tc
transition stnttj.1 •• still mere important goal of the theory is tA give en
interpretation ana a theoretical basis fo>" chemical concepts related to the
structu*"'* of nolc;cul-_s. A brief rrviou is given of thf two main approaches: a)
molecular orbital method , b) valence bend approach . Hartree-Fock theory, based
on the molecular orbital method, is successful in predicting molecular geomet-
ries but does not yield the correct dissocation products. £ better treatment of
tMf electronic rorrclrticn problem is given by the generalIZPC! valence bond
mettocl. Some of the concepts provided by quantum cnemistry which ere relevant to
the theory of the chemical bond ere discussed: a^ bono order, b) hybridisation,
c) conjugation, d) bent bonds, e) localized orbitals, f) multiple (up to
quadruple) bonds, q) behavior of the kinetic and potential energy upon bond
fotnation. Emphasis will be placed upon the problem: To what extent are these
coicepts dependent upon the particular method of approximation used in the
calculations?
33
T4
SOLAR PHOTOCHEMICAL CONVERSION: HYDROGEN GENERATION
JOSEPH RABANI
Energy Research Center and The Department of Physical Chemistry, The HebrewUniversity, Jerusalem, Israel
Among several promising approaches to the question of photochemical conversion
and storage of solar energy, the production of hydrogen from water is among the
most extensively investigated. If oxygen is the oxidation product, produced in
the same or a subsequent process by water oxidation, then energy storage is
achieved. The greatest obstacle to this form of photochemical energy storage is
the so-called "back reactions" between the photochemical transients, resulting
in the regeneration of the initial reactants along with the dissioation of the
energy which is converted to low temperature heat.
We believe that the key to achieve photochemical storage in the form of hydro-
gen lies in three related fields. Firstly, new photosensitizers and electron do-
nors and acceptors are required. The first step after the formation of an ex-
cited state by light absorption nust be an electron transfer -process. The phv-
sical and chemical required properties of the compounds involved can now be
formulated. It is now UD to the synthetic people to make, and the photochemists
to test them. Secondly, inhibition of the "back reactions" has been demonstrated
by using various microenvironments. Inhibition by 2-3 orders of magnitude may
turn the balance towards the competing (and desired) processes of oxidation and
reduction of water. Thirdly, catalysts can assist with the redox reactions. Both
powders and colloids have been employed.
The present state of these fields and the prospects for the future, all in re-
lation to solar enerqy conversion and storage is discussed.
34
T5
VINYL AZIDES. VERSATILE SYNTHONS.
ALFRED HASSNER, DEPT OF CHEMISTRY, Sl'NY BINGHAMTON, N.Y. USA andBAR-ILAN UNIVERSITY, RAMAT GAN, ISRAEL
Vinyl azides are ~n unusual class of organic molecules since they arecapable of reaction with nucleophiles or electrophiles. In additionthey are of active interest, because on thermolysis or photolysis theycan lead to reactive intermediates such as vinyl nitrenes, which undergofurther interesting intra or intermolecuiar insertions, "urther-more,vinyl azides &re canable of undergoing cycloadditions at both the ole-finic or the azido function. A l ^ fragmentation reactions have beenobserved.
The utility of sDecific vinyl azides in the repiosppcific formation ofalkylatec! ket ones, in novel amination of aromatics, in the synthesisof heterocycles and of cyanoketenes, and in formation of polycyclicindoles is illustrtrated.
35
I N V I T E DLECTURES
INVITED LECTURES W1 -
WEDNESDAY. APRIL 11
Wl
STABILIZATION OF IONS AND UNCHARGED COMPOUNDS BY CHARGE AND DONOR-ACCEPTOR
ALTERNATION.
J. KLEIN
Department of Organic Chemistry, The Hebrew University of Jerusalem, Jerusalem
Israel.
The polymetalation of unsaturated compounds was first observed on acety-
lenes less than twenty years ago. The last decade has witnessed the unexpected
polymetalation of a number of different classes of compounds, such as unsatura-
ted hydrocarbons (olefins and aromatics), or ketones. The presence of an
appreciable negative charge on the hydrocarbon part of the polymetalated com-
pounds where all the charges are delocalized in the same system, raised the
question of electron interaction in these molecules. The distribution of
charge in the system and the relative stabilities of isomeric compounds has
shed light on the relationship between these two properties and revealed a
new stabilizing effect, that is not a resonance one. These findings have
permitted to formulate rules that are helpful in predicting relative stabilities
not only of polyions but also of uncharged molecules. The most
stable product is obtained when the consecutive introduction of charges takes
place on the same set of starred atoms. This is true both for Kekule and non-,
Kekule hydrocarbons. The result of such a mode of charge introduction is the
formation of two alternating sets of atoms, the starred carrying the charge
of the system and the unstarred with a partial opposite charge. In the case
of hydrocarbon ions, all the atoms in the delocalized system are carbons, but
their character alternates from donor to acceptor. Similar rules for
stabilization apply to neutral compounds having more than one substituent with
a donor or acceptor character on a conjugated system. The substituents will
stabilize such a compound relative to its isomers if they are placed on odd
numbered (starred)atoms relative to each other when they are of the same kind
(donor or acceptor), but on even-numbered (one on a starred and the other on
an unstarred atom) when they are of different characters (donor and acceptor).
The result of such an arrangement is again donor-acceptor alternation along
all the atoms of the system.
39
W2
MACROMOLECULES ARE THE STUFF OF LIFE
H. EISENBERG
Department of Polymer Research, The Weizmann Institute of Science
Rehovot 76100, Israel
Only in our life time was the nature of the macromolecular state clearly estab-lished. Until shortly before the Society whose 50th anniversary we are celebra-ting to-day was founded, it was believed that large, well defined macromoleculesdo not exist. Following Staudinger it was soon accepted that many natural mate-rials were macromolecules, bonded to form long chains. Once the basic principlewas recognized that various atoms can join to form long chains, the macromolecularstate could be defined and studied.
The very important functional properties of biological macromolecules were quicklyrecognized and to-day we stand at the threshold of a major revolution. We arewitnessing the possibility to interfere with features of the biological machi-nery, in which macromolecules play a major role. The genetic message is linearlyencoded in DNA in triplets of four bases storing the information required tomaintain and reproduce a whole organism. Following transcription into RNA,trans-lation leads to polymerization of twenty odd amino acids into linear polypeptidechains. These, upon folding into active globular proteins, constitute the basicbiological machinery. Linear double stranded helical DNA threads of eukaryoticorganisms may be centimeters long but only nanometers across. For packaging innuclei of microscopic cells, DNA complexes with proteins, mostly hist^ne?.Hierarchies of structure arise, culminating in the chromosome. Though packaged,DNA must be instantly available for transcription and replication. DNA, histonesand non-histone proteins play both structural and functional roles.A complex of about 160 base pairs of DNA, wound around a core of eight (twicefour) histones constitutes the nucleosome, the basic repeating unit in chromatinstructure, discovered barely a decade ago. Long strings of nucleosomes, separa-ted by stretches of linker DNA and complexed with one additional histone, formirregularly unfolded "10 nm" fibers at low ionic strength, yet fold regularlyinto "30 nm" solenoids upon addition of monovalent or divalent ions. We focushere on presenting some basic aspects of the formation and significance of this"higher order" structure.
40
W3
RECENT STUDIES IN SOLID-STATE CHEMISTRY
Z. BERKOVITCr.-YELLIN, L. ADDADI, I. WEISSBUCH, J. VAN MIL, L. LEISEROWITZ,
M. LAiMOept. or Structural Chemistry, The '.teizmann Institute of Science, Rehovot, IL
A stereochemical correlation between structures of crystals of organic
compounds and their morphologies when grown in the presence of growth
inhibitors has been established. This knowledge has been successfully
applied to the efficient resolution of conglomerates, to the engineering
or organic crystals with desired morphologies, to the direct and relative
assignment of the absolute configurations of chiral molecules and the
directions of polar axis in crystals. A new m-:del for the spontaneous
generation of optical activity will be suggested.
41
•xf
i
W4
OPTICAL ABSORPTION, ELECTRON SPIN RESONANCE AND
RAMAN SPECTROSCOPIC STUDIES OF RADIATION PRODUCED INTERMEDIATES1
ROBERT H. SCHULER
Radiation Laboratory and Department of Chemistry, University of Notre Dame,Notre Dame, IN. USA 46556
Free radicals and other reaction intermediates can be produced by fast electron
radiolysis in su f f i c i en t l y high concentration that the i r st ructural and k inet ic
properties can be studied by various CW and time-resolved spectroscopic tech-
niques. Experimental arrangements at the Notre Dame Radiation Laboratory cur-
rent ly permit observation of radiation produced intermediates by opt ical ab-
sorpt ion, electron spin resonance and resonance P.aman methods on microsecond,
and in some instances s'norter, time scales. By coupling i n f rma t ion obtained
from these various approaches with auxi l iary information fro.", product analysis
and time-resolved conductivity ineasurements one i5 frequently able to obtain a
rather complete picture of the nature of the reaction intermediate. The value
of combining various approacnes to examine intermediates from d i f fe r ina vantage
Doints is i l l u s t ra ted by results from studies of seiniquinone radicals using ab-
sorption spectroscopic, electron spin resonance and resonance Raman methods.
(1) The research described herein was supported by the Office of Basic Energy
Sciences of the Department of Energy. This is Document Ho. i'JDRL-2521 front
the Notre Dame Radiation Laboratory.
42
W5
IONS AND LIGHT;FROM THE ORIGIN OF LIFE - TO BIOMEDICAL APPLICATIONS
C. LIFSHITZ; Department of Physical Chemistry, The Hebrew University of Jerusalem
Jerusalem 91904, Israelf
I t has been demonstrated in recent years quite convincingly that the combinationof ions and l ight in interstel lar space is responsible for the origin of l i f e on
earth. Advances in experimental techniques in the laboratory - in mass spectro-
metry (MS/MS, CAD etc. ) , as well as in l ight sources (the Synchrotron, the
j LASER) - have enabled experiments which were hitherto impossible to perform. The
! structures of many organic ions in the gas phase are now quite well established
'. experimentally and from ah initic calculations. Isomeric structures play an im-
| portant role for stable, as well as dissociating ions. Considerable progress has
"f been made in the fields of spectroscopy (electronic and vibrational) of ions,
single and multiple photoionization of molecules (PI and MPI), unimolecular
fragmentation mechanisms of organic ions, gas phase ion-molecule reactions (IMR),
fluorescence and radiative lifetimes of ions and ion photodissociation. Some
striking examples wi l l be discussed. In analytical biomedical applications the
drive is towards ever increasing higher molecular weight compounds of low vola-
t i l i t y . Analyses of peptide antibiotics, penicilines, vitamins etc. can now be
'. performed by LASER desorpt ion and Fast Atom Bombardment techniques.
E. Herbst and W. Klemperer, Physics Today, 29_, 32 (1976).
J . L . Holmes, F.P. Lossing, J.K. Terlouw and P.C. Burgers, J . Am. Chem. Soc. 104,293 (1982); W.J. Bouma, R.H. Nobes and L. Radom, i b i d . 104, 2929 (1982).
S.P. Goss, J .D. Morrison and D.L. Smith, J . Chem. Phys. 75., 757 U981 ) .
J.P. Maier, Ace. Chem. Res. 1_, 18 (1982).
H. Barber, R.S. B o r d o l i , R.D. Sedgwick and A.N. Ty le r , Biomed. Mass Spectrom. 8_,492 (1981).
43
Vb
THE ROLE OF PiiLROMON'ES IN" INTEGRATED PEST CONTROL
A. SHAM
Department of Chemistry, iien-Gurion University of the Negev,Keer Sheva,34120, Israel
Tne endless battle between mankind and pests (mainly insects'! for food and
other agricultural products is on: we constantly starch for more efficient
and safer ways, than arc in use today, to minimize food and other products
loss. Pesticides do not solve the problem, albeit eased for awhile, but in
the recent years aggravate it, as a result of their massive uiiil uncontrolled
use in pest control. Insects develop resistance against th. chemicals used
everywhere; ecological and pollution diasters are common; and biological
equilibrium is easily destroyed. Furthermore, cost of these chemicals is
constantly rising.
Several new approaches have been tried in recent years. Examples are the U=L
of predators and pathogenes specific to target pests, freeing sterilized irales
to reduce reproduction and lately, monitoring of pests by pheroraones for better
timing and a more efficient way of pesticide application.
The preliminary positive results of mass trapping and especially of disruption
of communication between males and females by sex pheromones, or inhibitors,
strengthen the hope for their having the key role in integrated pest control.
This way of management is based on better understanding of the biological,
electrophysiological, chemical and other aspects of insect behavior and
pheromone activity; and most important is studying the possibility of mutation
development (as equivalent to resistance to pesticides] under wide use of
pheromones in their future application.
44
W7
ISRAEL'S CHEMICAL INDUSTRY - CENTENNIAL(OF WHICH ONLY HALF IS HISTORY)
Z. ZURRKoor Chemicals Ltd.Beer ShevaIsrael
After almost exclusive emphasis on agriculture in pre-state pioneering period
(1920-50),there followed a rapid development of industry during the f i r s t 30
years of statehood (1950-80),with Chemical Industry high on p r io r i t y l i s t .
Despite th is e f fo r t ,our Chemical Industry,with i t s close tc $ 2 b i l l i o n value of
production and exports of 5800 mi l l ion value (about 40?.- of total),employing some
25,000 people,is s t i l l lagging behind the industr ia l ized countries of the West,
and i t s most devloped branches are these serving agricL;lture(Ferti • izers,Plast ics
for i r r i ga t i on e t c . ) . The future of Israel depends more on i t s economical than
P' i l i tary strength and present state of things here is a strong memento to th is
e f fec t . Economical strength depends on thr iv ing,export oriented,thechnologically
and sc i en t i f i ca l l y advanced industry. Our Chemical Industry,small as i t i s ,
provides adequate basis for future development,and u t i l i z a t i o n of opportunities
which arr ise with the changes taking place in the Industry world-wide: Change
from economics of scale to one the sophistication and f l ex ib i l i t y ( sma l l is
beaut i fu l ) . Change from dependance and wasteful use of energy,raw materials andother physical resources (ecology), to more dependance on highly sk i l led and
educated workforce. Change from marketing style by price or monopoly (of
resources or proprietary r'"ghts) to one of service and cooperation. These
changes are an opportunity :>.nd also a challenge for Israel i Chemical Industry
for the second»coming hal f of i t s centennial.
45
ws
ELECTROLYTIC CONDUCTION MECHANISMS IN NONPOLAR SOLVENTS
E. GILEADI
Dept. of Chemistry, Tel-Aviv University, Tel-Aviv 69978, Israel
Unusually high electrolytic conductivity is observed for H_0+ and Oh" in water
and similar protic solvents (mostly alcohols) due to a nonStokesian hopping
mechanism, proposed first by Grotthus. A similar mechanism is assumed to
account for the observed conductivity in pure sulfuric and phosphoric acids.
A study of the enhancement of the conductivity of acids as a function of theconcentration of water in mixed solvents of water/acetonitrile and water/tetra-hydrofurane showed no effect until the concentration of water reached about 5f-;.or U * of that in pure water.
A similar study of the conductivity of Br" in mixtures of bromine and nitro-
Denzene confirmed that a hopping mechanism is predominant in these nonpolar
solvents. Hopping becomes important when the concentration of bromine in the
solvent mixture exceeds 2f>i, whic. is ££ 1Q% of pure bromine.
When a dilute solution of bromide in pure bromine is frozen, the measuredconductivity increases by a factor of about one hundred. This is consistentwith the hopping mechanism of electrolytic conduction and the existence of along range order in the solid.
The conductivity of I" in liquid I_ exhibits similar characteristics. In both
I7 and Br, the walden product decreases with increasing temperature. Such behav-
iour is expected if a nonStokesian mechanism of conductivity is predominant and
is observed in aqueous solutions only for the H30+ and the OH" ions.
Solutions of KBr and Al?Br in an aromatic hydrocarbon were developed as a plat-ing bath for Al. The molar conductivity is unexpectedly high for such a nonpolarsolvent and increases rapidly with increasing concentration. The Walden productdecreases with increasing temperature in concentrated solutions. All the experi-mental observations are consistent with the assumption that aggregates of ionsand neutral molecules are formed in this system and hopping of ions betweenaggregates 1s the mechanism giving rise to the high conductivity.
46
POSTERSESSION TTUESDAY, APRIL 10. 1984
SPECTROSCOPY
SURFACE CHEMISTRY
PHOTOCHEMISTRY
ORGANIC SYNTHESIS
ORGANIC REACTION
MECHANISM
INORGANIC CHEMISTRY
ANALYTICAL CHEMISTRY
TA1
DEVELOPMENTS IN THE APPLICATION OF R-IR AND RAMAN SPECTROSCOPYTO POLYMER CHEMISTRY
B.J. BULKIN
Polytechnic Institute of New York, Brooklyn, N.Y. 11201, USA
Vibrational spectroscopy has been used for many years to study various aspects
of polymer chemistry and structure. Examples such as the analysis of polymer
crystal Unity are well established for several cases. In recent years, there
have been major advances in instrumentation which have expanded the horizons
for use of vibrational spectroscopy in the polymer field.
Application of Fourier transform infrared (FT-IR) techniques as well as new
computational approaches on digital spectra to polymer problems have signif-
icantly changed the role which infrared spectroscopy can play in addressing
polymer problems. This will be illustrated from work in our laboratory on
tne dynamics of polymer degradation under varying environmental conditions,
and on evaluation of curing reactions.
Raman instrumentation has also evolved in this period. One of the most
interesting new developments is rapid scanning Raman spectroscopy, which we
are applying to polymer problems for the first time. It will be shown that
this technique can provide unique information about the dynamics of polymer
crystallization. Indeed, it is one of the only ways that crystallization
can be viewed at the molecular (functional group) level, and it offers the
potential of separating the stages of tne crystallization process.
49
TAJ
DEUTERIUM NMR OF DEUTERATED PROBES
DISSOLVED IN STRETCHED POLYETHYLENE
H.E. GOTTLIEB AND Z. LUZIsotope Department, The Weizmann Ins t i t u te of Science, Rehovot 76100, Israel
Deuterium NMR spectra of deuterated organic probes ( including benzene-dg,
chloroform-d. acetone-dg, pyr id ine-d 5 < a n ( j 0 . an<j p-xylenes-d-|Q) dissolved in
stretched polyethylene (PE) were recorded for two polymer samples, viiz.. low
density PE, and cross- l inked middle density PE. A l l spectra exh ib i t quadrupole
s p l i t t i n g s due to the f i n i t e average quadrupole in teract ion of the various
deuterons. Their behaviour is typ ica l of ordered systems in which the probe
molecules undergo fast d i f fus ion (on the NMR time scale) between d i f fe ren t
solvat ion s i tes suchas e.q. in l i qu i d c rys ta ls . The magnitude of the s p l i t t i n g s
was studied as a function cf probe concentrat ion, teniperature and the degree of
s t re tch ing , \ . The observed quadrupolar s p l i t t i n g of a l l probes studied is
qui te small (less than 5. of the .so l id state value) and shows a sigmoidal
dependence on the probe concentration. For the low density PE sample the
s p l i t t i n g has a perfect l inear dependence on the elongation fac tor . In un i -
d i r ec t i ona l l y stretched PE the asymmetry parameter of the quadrupole hamil-
tonian n is zero, but in samples stretched successively in two perpendicular
d i rect ions n ^ 0.
50
TA5
NMR SJUDY OF THE LYOTROPIC MESOPHASES OF THE
DSCG-WATER SYSTEM
D. GOLDFARB*. M.M. LABES**, Z. LUZ*. D. PERAHIA* AND R. POUPKO*.*Isotope Dept., The Weizmann Institute of Science, Rehovot 76100, Israel
**Dept. of Chemistry, Temple University, Philadelphia, Penn. 19122
The lyomesophases of the disodium cromoglycate (DSCG) water system were studiedOH
by D , 0 and Na NMR. Depending on the temperature ana concentration of DSCG
three different mesophases exist: below -4°C a relatively highly ordered uni-
axial smectic like phase (phase III) which had not been previously reported ^
exists. Above -4°C this phase transforms to either the N or M phase. The
dividing line between these two phases is at about 18 wt.* DSCG. The N phase
which appears at the lower concentration end is a nematic phase which reorients
in a magnetic field whereas the M pnase is smectic like and does not reorient
in a magnetic field. There is no discontinuity in the ordering characteristics
of both the water and the sodium ions upon the N Z M transition,suggesting that
these two phases have similar ordered structures. These are believed to be
columns of stacked DSCG molecules which in the N phase exhibit only orientation-
al order while in the M phase they possess positional order as well, and are
packed in an hexagonal array. The phase transition from the N,M phases to phase
III is accompanied by a marked change in the water ordering which can be obtain-
ed from the ^D and " 0 quadrupolar splittings of enriched water. The ^ N a
spectrum is particularly sensitive to this transition where a large change in
both quadrupolar splitting and linewidth takes place. As the N and M phases,
phase III is a type II phase (A>;O). however its detailed structure is still23unknown. The study of the Na spectra as function of the DSCG concentration,
temperature and added NaCl as well as other electrolytes indicates the existenceof two solvation sites in which the sodium ions experience quadrupole interac-tions of opposite signs. It is suggested that these sites correspond to (I) Na ,forming intermolecular electrostatic bonds within the columnar structure of theDSCG mesophases and (II) hydrated sodium ions dissolved in the bulk environment.
51
TA4
RAMAN STUDY OF SOLID TEMPERATURE INDUCED AUTO-IONIZATION
F. BOLDUAN*. H.J. JODL*. A, LOEWENSCHUSS***Facbbereich Physik, Universitat Kaiserslautern, W.-Germany
**Dept. of Inorganics Analytical Chemistry, Hebrew University, Jerusalem, IsraelRaman spectra of solid condensed from gaseous NO./PLO, were investi-
02NN02 dimer is formed. Deposition at
02N0N0 isomers.
gated. When deposited at 80 K the15K produces additionally bands of the N02 monomer and the
Warming to 180 K induces auto-ionization to NO+NOf which remains stable over
the 15-180 K range. The transition is probably an intermolecular processinvoked through the low energy latt ice or v^ twist vibration of the dimer.
! T=80K
i \J\
n atIcm"1!
150 100 50Frcqutncyshif t Ccm"1]
Raman spectra of condensed NO2/N2O..a) As deposited at 80 K. ILow frequencies: !a) As deposited at H K.
(Sym. N20* vibrational lflx fts <jeD0Site(j a t 80 K ' ^Sym# N20* yibrationa'nodes identif ied.) ' *> modes identified on t i ,
b) After annealina to 180 K i b ) A f t e r annealing to | N02 monomer modes desig-b) After annealing to 18U K. i m K flnd r e c o o l i n g n a t e d b y a m ) w s > * .c) After cooling to 14 K. j to 15 K. ; Bands of unsymm. N20u.
: fb) After annealing to 180 K.1 \c) After recooling to 14 K.
TAB
UPPER AND LO"JER DOUNDS TO THE RESONANCE POSITION AND WIDTH
NI1ROD MOISEYEV
Dept. c f Chemistry, Technion — I s r a e l I n s t i t u t e o f Tecnnolngy
Using toe he r r r i t i an rep resen ta t ion of tne complex coord inate method t h a t r e -
cen t l y has been developed, uoper and lower bounds f o r the approximate resonance
p o s i t i o n and w id to are fo rmu la ted , rte nave proved t h a t f o r a given est imate o f
tns resonance p o s i t i o n and w id tn the exact s o l u t i o n i s embedded i n the sur face
of a crescent aeino pa r t o f an annular r i n n whose i nne r and cvjter r a d i i can De
obtained o,' variational calculations. An i l lustrat ive numerical example is pre-S2nted.
53
TA6
ABSORPTION SPECTROSCOPY FLUORESCENCE SPECTROSCOPY AND EMISSION
QUANTUM YIELD MEASUREMENTS OF LARGE MOLECULES IN PLANAR SUPERSONIC EXPANSIONS
A. Amirav, M. Sonnenschein and J. Jortner
Department of Chemistry, Tel-Aviv University 69978, Tel Aviv, Israel
Absorption spectra, fluorescence excitation spectra and fluorescence quantum
yields from photoselected vibrational states of S, manifold and higher excited
states of large molecules cooled in planar supersonic jets were determined using a
pulsed xenon lamp and a monochromator. Planar supersonic expansions from a nozzle
-•it, wnich are characterized by a long optical pathlength and by high densities
in tne interrogation region are suitable for the study of absorption spectra of
large molecules in jets. The use of a pulsed xenon lamp as a light source made
it possible to record the lamp-induced fluorescence (LMIF) spectrum simultan-
eously with the absorption spectrum. The ratio between the LMIF signal and the
absorption signal of each spectral feature give the relative quantum yields Y
(relative to the electronic origin (0) of S^). These relative Y values can be
calibrated using a reference molecule to give absolute emission quantum yields
from photoselected vibrational states.
The following molecules have been studied: Anthracene, per deuteroanthracene,
.ijthylanthracene 9-cyanoanthracene, 9,10-dichloroanthracene, 9-bromoanthracene,
9j«<-dibromoanthracene, tetracene, perylene pyrene, phenanthrene, fluorene,
earbazole, fluorenthane, naphthalene aniline, azulene, pyrazine.trans-stilbene,
4-chloro-stilbene, DABCO, ABCO, and other molecules.
54
TA7
DEUTERATION EFFECTS IN THE MULTIPHONONRELAXATION OF CRYSTALS
R. ENGLMAN*. W.SIEBRAND***Soreq Nuclear Research Center,Yavne,Israel••Division of Chemistry,National Research Council, Ottawa,Canada
4 2+Replacement of H«0 by D«0 increased the lifetime of the T, state of Mnin CsMnCU.2H?0 from 0758 ms to 9.2 ms at 1.6K. However, the shape of thephonon siae-band of the optical transition was only sl ightly changed bythe substitution.The paradox is resolved by noting that Franck-Condon factors for radiation-less transitions fa l l off at least exponentially with the number of vibra-tional quanta. This makes high-frquency oscillators strongly favoured alsoin solids. I t is therefore possible to explain the fifteenfold decreasein the relaxation rate upon deuteration solely on the assumption that onlyOH- and OD-stretch mode'ii participate in the decay process. The parametersrequired for a quantitative explanation are taken directly from spectro-scopic data. The phonon side-band is essentially governed by the effectivephonon density of states appropriate to the transition and is irrelevantto the decay rate.The probable mechanism whereby an optically excited metal ion activatesOH-stretch phonons involves a change in the delta-bonding between the metalion and the water molecule. We have indications that this bonding depends
I delicately on the spin configurations of the metal ion orbitals and thatsmall changes in bonding can produce relatively large changes in decay
\ rates. '\ We suggest for future research in solids that nonradiative decay, throughX i ts specificity for hinh-frequency vibrations, be used as a probe of subtle• quantum-mechanical interactions between relatively remote atoms.
55
TA8
TWO DIMENSIONAL CORRELATION NMR SPECTROSCOPY IN ROTATING SAMPLES
S. VEGAIsotope Department, The Weizmann Institute of Science, 76100 Rehovot, Israel
During the last few years magic angle sample spinning (MASS) has evolved to an
important technique in high resolution NMR spectroscopy on solids. Specifically,
of all the various high resolution solid state methods developed in the last
twenty years, MASS is one of the most widely applicable and useful. The
"liquid like" spectra obtained during MASS experiments make this technique
favourable over other NMR techniques. Lately it was demonstrated that MASS
can be incorporated into a number of other pulse NMR experiments. In general,
the approach taken is to employ a multiple pulse technique to manipulate parts
of the nuclear spin Hamiltonian in a MASS experiment. The results of these
experiments consists of enhanced and highly resolved spectra.- Techniques which
were combined with MASS are homonuclear dipolar decoupling techniques, chemical
shift scaling and double quantum NMR. In addition, these techniques can also be
incorporated into two dimensional NMR experiments. In particular 2D experiments
were performed to detect heteronuclear chemical shift correlation and double
quantum coherences in rotating samples. The general approach of these experi-
ments involves homo- and heteronuclear decoupling during the evolution period
followed by a coheronco transfer or mixing period and ended by a detection period
with heteronuclear docoupling. Several methods for coherence transfer were
examined experimentally and theoretically. In all MASS experiments which were
combined with multiple pulse techniques additional spectral lines were detected
at frequencies equal to multiples of the frequency of the sample rotation. The
origin of these rotor frequency lines was explained by using the Floquet
formalism.
56
TB1
FRAGMENTATION AND EXCITATION OF MOLECULES IN HIGH ENERGY MOLECULE-SIJRFACF
COLLISIONS
RON ELBER, R.B. GERSER
Department of Physical Chemistry, The Hebrew University of Jerusalem, Jerusalem,ISRAEL
Molecular fragmentation on vessel walls is of fundamental importance in many
chenical processes. Very l i t t l e is known on the deta i ls o f such react ions from
a first principle-theoretical point of view. In this research we investigated
the mechanisms of molecular dissociation, upon collision with a surface, in or-der to establish a first principle physical model for such reactions. Thisstudy is done in collaboration with the experimental group of Professor A.Arrirav of the University of Tel Aviv.Ue obtained the following results in our research:
(a) The rotation excitation is dominant. The vibrational energy of the scat-tered molecule (below the dissociation threshold) is smaller by orders of mag-nitude than the rotational one:(b) I t is shown that the dissociation follows a rotational mechanisi.i: Thetorque exerted by the surface on the molecule results in large rotational exci-tation and thus in "Centrifugal bursting":(c) A simple estimate is given for the velocity dependence of the dissociation .
probability. The comparison between the theoretical oredictions and the experi-ucntal results of the dissociation of I? nolecule on I'.gG surface was excellent.
(d) The details of the process (fragments' velocity and annular spectra) is
described by a successive multiple collision mechanism.The following features were obtained:-(1) 'iainbow spike in the fragments' angular spectra. In addition those soectra
include a specular dip and a very broad background.
(2) Doubly peaked velocity distribution.Those observables might be very useful in studying different types of surface-
molecule interactions at the high energy regime.
Conclusions: Understanding was reached of basic dynamics of diatomic molecular
excitation and dissociation in high energy collisions with solid surfaces.
57
TB2
THEORETICAL STUDIES OF MOLECULE-SURFACE SCATTERING: R-KATRIX TECHNIQUES
K. B. WHALEY, J . C. LIGHTJames Franck Ins t i t u te and Department of ChemistryUniversity of Chicago, Chicago, I l l i n o i s 60637, U.S.P.
Quantum mechanical treatment of the d i f f rac t i ve and rotat ional ly inelast ic
scattering of molecules from corrugated surfaces presents a major theoretical
challenge because of the large number of degrees of freedom involved and the
many-bodv nature of the interact ion potent ia l . We have used a combination of
single (Wigner) R-matrix and propagative R-matrix methods to study the rota-
t iona l l y ine las t ic and d i f f rac t i ve scattering of H-, D?, and HD frorr rretal sur-
faces ( P t ( l l l ) and A g ( l l l ) ) . Standard close coupling fon-a l is r for ro tat ion-
a l ly ine last ic co l l is ions with a f l a t surface is extendable in both instances
to include the ef fect of coupling to addit ional decrees of freedom. The Wigner
R-natrix allows use of a phenomenological d iss ipat ive potential to nodel phonon
losses while the propagative R-m.atri x may be used to construct, and propagate
T-matrix elements for perturbative d i f f rac t i ve coupling between zeroth order
rotat ional ly ine last ic solut ions. Since d i f f rac t i ve exci tat ion is a minor
ef fect re la t ive to rotat ional exci tat ion of HD on these close packed metal sur-
faces, th is system is eminently suited for a distorted wave Born approximation
to the T-matrix elements between d i f ferent i n i t i a l and f i na l magnetic quentun
and d i f f rac t i ve states. Investigation of simple parametric forms of the mul-
t i p l e components ( iso t rop ic , anisotropic : and d i f f rac t i ve ) of the molecule-
surface potential carried out with both Wigner and propagative R-nvitri/v rr.ethcds
is compared with extensive experimental results for the molecular hydrogen -
Ag(111) system.
58
TB3
CHEMISURPTION OF HYDROGEN ON COPPER:
A DYNAHICAL STUDY
A.T. YINNOH, R. ELBERDepartment of Physical Chenistry, The Hebrew University of JerusalemJerusalem 91904, Israel
The che.nisorption of hydrogen on copper surfaces (an important step in the re-action sequence of a variety of heterogeneous catalytic reactions) is sinulatedoy classical trajectories conputations. The results' are used to extract 3physical picture of tiie dissociation fro.i a f i r s t principle point of view.The conclusions reached are the followinc;:
(1) The enerny barrier for nolecular fragmentation is site dependent and smallerat step ed^es than on terraces or on the f la t face of the crystal;
(2) Toe effective recombination rate is determined by competition between instan-taneous dissociation and recoi.it) ination;.
(3) The stepped surface asymmetry reduces the recoiibination probability andhence increases t ie adsorption rate.
Based on a conpariscn between exoeri.iental results and on tneoretical ones, thefcl lo/ inj j reaction nechanis.. is proposed: A hydrogen molecule is pulled apart jyadjacent surface atoi;s. To is causes an effsctive transfer of the normal trans-lations! energy of toe molecule to parallel t ranslat ion! energy of tne disso-ciated atons which becir, hep^inc over the surface, diffuse and are aDsoroed ata fixed site folio,rinn iuosequent loss uf or\2rdy.
TB4
ADSORPTION OF HYDROGEN GAS ON A L i V CRYSTAL
V. DUVAL*. M. SHAPIRO*, R. TENNE***Dept. of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel**Dept. of Plastic Research,Weizmann Institute of Science, Rehovot 76100, Israel
The mechanism of adsorption of hydrogen atoms on a Li+F~ crystal, is an importa-
nt step towards the understanding of the adsorption of hL molecules on the
crystal. These results can be important for the improvement of solar cells of
the photoelectrochemical type. We present a theory in which we consider three
electronic configurations associated with a hydroqen atom in contact with the
crystal. These configurations are: H with the perfect crystal, H~ with the
crystal + hole, H + with the crystal + electron. Our aporoach is based on the
semi-empirical Valence-Bond method, from which we obtain adiabatic and diabatic
potential energy surfaces. The main results of our study are-: (1) The most
probable adsorption site is the center of the cell. (2) The adiabatic
potential energy barrier for penetration to the first layer is about 0.6eV, and
about 2.2eV from the first to the second layer, making it nossible to consider
the existence of penetration by tunnelino of a hydroaen atom. The model was
extended to treating the effect of a hydrogen atom imbedded in the surface or
trapped in the first layer, on the adsomtion of H+ on the crystal surface.
These studies shed light on the mechanism of formation of hydrogen molecules in
the vicinity of the photoelectrochemical cell electrodest
60
TB5
FORMATION AND STRUCTURE OF SELF-ASSEMBLING MONOLAYERS. ORDER-DISORDER AND
KINETICS STUDIES.
J. GUN, J. SAGIV
Dept. of Isotope Research, The Weizmann Institute of Science, Rehovot, Israel
Artificial organized films, initially inspired from biological systems like
membranes, are becoming a very important aim of modern chemistry. The self-
assembly technique allows the construction, in a controllable and reproducible
manner, of surfaces coated with organized monolayers or multilayer organic
films. This approach presents some important advantages over the classical
Langmuir-Blodgett technique. The formation and structure of adsorbed mono-
layers of long chain acids and a long chain silane are investigated using
Fourier transform infrared spectroscopy (FTIR) and wettability measurements.
Polarized and non-polarized attenuated total reflection (ATR) spectroscopy are
the two FTIR techniques employed in this study. RA spectroscopy of monolayer
films on aluminium mirrors is shown to be a useful tool in the detection of
order-disorder transformations accompanying interactions of a highly oriented
monolayer with a chemical external agent. Covalently bonded silane monolayers
are shown to be perfectly stable under conditions causing a major deteriora-
tion of the structure of adsorbed fatty acid films. The adsorption of fatty
ncids on aluminium is found to involve physical forces only. ATR spectroscopy
on Si and ZnSe prisms provides quantitative data on the kinetics of monolayer
formation and solvent inclusion and its evaporation from tho film structure.
The results are interpreted in terms of the mode of film-to-surface binding
and the shape and size of the solvent molecules.
b\
TCI
TIME SEQUENCED PULSE RADIOLYSIS LASER
PHOTOLYSIS SPECTROSCOPY
HAIW LEVANON and ODED GONEN
Department of Physical Chemistry, The Hebrew Universi ty of Jerusalem, Jerusalem91904, Israel and Radiation Laboratory, University of Notre Dame, Notre Dame,I n . 46556, USA
Experiments employing sequenced pulse rad io lys is laser photolysis on Z i n c ( I I ) -
Tetra-(N-Methyl-4-pyr idyl) porphyrin chlor ide (P) in aqueous solut ions are pre-
sented. This setup enables photoexcitat ion of the system before, during and af-
t e r the t rans ient radical formation. Two types of reactions are t reated:
(1) The r e a c t i v i t y of photoexcited t r i p l e t PT as compared to i t s ground state P
with i-PrOH and B r i " radicals in redox react ions:
T - P - + ( C H ) C n + H +
P T •* P < + + 2 B r "
(CH3)2fc0H + PT - P - + (CH3)2Cn + H
(2) The dynamics and kinetics effect of photoexcitation on the porphyrin nround
state-radical (P* + or P") systen.
P " + hv ->• ?'-*
where P " * is suggested to be a quartet state.
62
it::
QUENCHING OF TRYPTOPHAfl PHOSPHORESCENCE IN ALCOHOL DEHYDROGENASE
FROM HORSE LIVER AND ITS TEMPERATURE DEPENDENCE
N. BARBOY, J . FEITELSON
Dept. o f Physical Chemistry, The Hebrew Un ive rs i t y o f Jerusalem, JerusalemIsrael
The phosphorescence of Alcohol Dehydrogenase from Horse Liver (LADIi) can be
observed at room temperature. The quenching of th is long-l ived l i gh t enission,
which comes from a tryptophan residue del l buried wi th in the in te r io r of the
enzyme structure was treasured. The rate constant for the quenching by tneP '-1 -1
small oxv-en no lecu le and by the I ion were £onnd t o be 1.4xlC J " sec andq -1 -1
10° '" sec • respoetivelv at roo1". temperature. Th: temperature dependence o^
the quenchirn yields an activation energy o~ about 14 kcal/nole. This activa-
tion enerjy and t'i<? cleaning of the acconpanvin-: larqe pre-exponential factor18 1 -1in the ".rrhenius equation, A = 10 " 'sec , aro discussed in terns of a
Tods! in /hich tne quencher threads its way through the Drctein net'/ork. I tis proposed that the diffusion of t:ie quencher is .nade possible by temporal"•neltinc" of local structures .-/ithir. the ^rotein. These teinporarily dis-ordered locations provide on the one hand! channels for the diffusinq quenchernolecule ind on the other hand causes f ie entropy of activation in".„ - \... c,ex?(AS /3)exn(-AH , >VP to assune 3 laruo positive value.
TC3
FLUORESCENT DYES AS PROBES FOR ADSORPTION STUDIES ON CLAYS
Z. QRAUER^, D. A V N I R ^ and S. YARIV(b^
Departments of Organic Chemistry'8' and of Inoroanic and Analytical Chemistry^The Hebrew University of Jerusalem, Jerusalem "1904, Israel.
We wish to report that ornanic cationic fluorescent dyes proved to beuseful probes in styding adsorption and flocculation ohenonena in clays. Two
exDendable snectite clays, namely montmorillonite and 1 aconite, were used as
absorbents in the form of an aqueous suspension, with the followina dyes as
adsorbates: rhodamine B, rhodamine 6G, nyronine-Y, DODCT (a cyanine), thionine.
crystal violet. An interesting interolay between various dye-species, as a
function of surface coverane, ultra-sonic treatment and a^in", was observed.
These species include monomeric adsorbed molecules, adsorbed dimers, and dye
molecules trapped and concentrated within tactoidal cages. Various adsorption
conformations could be sunaested in some cases. All these species cave rise to
specific blue or red shifted absorption (metachromasy) and emission maxima.
Follow up of these new peaks as a function of concentration chanqes was found
to be convenient and useful tool in determination of saturation points. These
pave rise to new types of adsorption isotherms. In many cases, the ratio
within the adsorbed species was found to be sensitive to ultrasonic treatment.
The use of this energy source in connection wi1:h absorption and emission spectra
of adsorbed molecules on clays, is novel. Double and triple energy transfers
between co-adsorbed dyes have been observed (E.o., rhodamine 6G - rhodamine B).
The use of such enerqy Transfers in studying ornano-clay suspensions will be
demonstrated. These and other investigations on photoorocesses as a tool
in studyinqadsorption phenomena, are in proaress.
Soonsored in part by the Israel-i).S. B'inational Foundation (to D.A.) and by
the Ben-Gurion Foundation (to Z.G.)
64
TC4
A PULSE RADIOLYTIC STUDY OF THE APPLICATION OF 1,2,4,5-TETWCTHOXYBENZENE AS
AN ELECTRON TRANSFER REAGENT IN SOLAR ENE^Y CONVERSION SYSTEHS
M. BRANDEIS, R. E. SASSOON, J . RABANI J
Energy Research Center and Dept. of Physical Chemistry, Hebrew University ofJerusalem, Jerusalem 91904, Israel
Alkoxybenzenes have been well-documented in the l i t e ra tu re as orqanic quenchers
in photoinduced electron transfer systems. 1,2,4,5-Tetraniethoxybenzene (TMeOB)
may serve as a very good candidate in l i g h t energy conversion systems involving
cleavage of water, pa r t i cu la r l y in view of i t s hiqh redox potent ial (ETM_«i5+/0"
+1.06 V vs. NHE) and i t s hinh s o l u b i l i t y in water which nay nemi t oxidation o*
water to oxygen in a very wide pH ranae. I t may also be very useful in poly-
e lec t ro ly te systens current ly under study iTf---our laboratory due to i t s lack of
electronic charqe.
In th is study the radical cation o r TMeOB was produced on electron pulse i r r a -
diat ion o* ^ saturated solutions of TMeOS in the presence of t ha l l i un ( I ) at
DH 4. The rate constant ' o r the fomiation of T!teO3#, k(T12++T>op.), was foundO i l t I •
to be equal to (1,0±C. 1 )xlO' '•" s . The l i f e t i w of the radical is relatively
long and i t disappears in a second-v^der radical duierization process with a
rate constant of (2.4±0.3)xi:'- '-Hs"1 . The visible absorption spectrum of
TMeOB* his also been determined and is found to oossess a sharp peak at 450 nm
(e^ax • 5880 i r 1 en"1).
T!>e rate o^ disappearance of the TMeOR* radical cation was found to increase by
a facto" ox nreater tuan tii^ee orders o r naonitude on adHition of colloidal
RufL which -!s a catalyst for the oxidation o* -inter to nxyfen. Steady-state ex-
periments, where oroduct analysis nay be carried out, are presently underway to
determine i r the disappearance of trie TlieOD- species is acco^nanieH by the pro-
duction of oxygen -fron v/atet.
Acknowledgement;This Research was supported by The Schroiber Foundation and by the National
Council for Research and Dovelonment.
65
TCS
PHOTODISSOCIATinrJ IBr LASER AS A CANDIDATE FOR SOLAR DOWERED LASER
H. BONY, M. SHAPIRO, R. NAAMAN, A. YOT,EVThe Weizmann Institute of Science, Rehovot 76100, Israel
In principle, one of the more efficient ways of harvesting solar enercy is the
direct conversion of light to chemical energy. However a basic limitation in
such applications is that only a well defined and very narrow band of the solar
spectrum is ever used, Liqht outside the effective band leads to heat or
unwanted products. In order to overcome this Iirait3ticr we -:roDosc to orocess
the light so that the energy contained in it could h? channeled into the desired
spectral bands. Our approach is based on drivino lassrs by neans concentrated
solar radiation. The laser light thus obtained could be used directly for a
variety of photochemical applications* In order to ounm the laser we propose
to use a central receiver capable of generating radiation fields intense enough
for this puroose. The fraction of solar radiation not used for laser
can then be filtered and converted to electricity in the usual way = .Je have2
investigated the photodissociation of IBr to I and Br in the P,^ excited
state. In this way we hope to convert solar eneray to laser enemy at a
relatively high efficiency. The population inversion of the Br atoms, formed
in the process, as a function of excitation wavelenqth, was first calculated
theoreticallv. The calculated abundance of excited ( ?1/0) Br atoms, as' n I / 4.
compared to ground ( P3/0) Br atoms, is 3:1 at the center of the absomtion
line. This is in nood agreement with available exnerinental data A flash-
lamp pumoed Br laser, operating at 2,7y, based on the above process, was then
built and its performance tested as a function of IBr pressure and intensity of
the pump source.
66
TC6
IN SEARCH OF MODE SELECTIVE CHEMISTRY:
INFRARED MULTIPHOTON DISSOCIATION OF CH3-SCCS-CD3
S. RUHMAN, Y. HAAS
Department of Physical Chemistry and The Fr i t z Haber Research Center forMolecular [tynamics, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
The poss ib i l i t y of inducing a selective uninolecular decomposition of an isolated
molecule by inf rared milt iphoton exci tat ion (IR'IPE) is experimentally investiga-
ted. The iiolecule used in th is study is 1,1, l - t r ideutero-2,5-di thiahex-3-yne,
C-U-SCCS-CD,. I t was chosen because i t s infrared spectrum contains bands asso-
ciated with e i ther the CD, or the CH, group, both wi th in the tuning range of the
COo laser. The J-C^C-S ?roup was thought to behave as a f i l t e r , impeding fast
intramolecular energy transfer and the reaction (a simple bond f i s s i o n ) , can be
fo l laved in real tir,;e. The experiments were carried out using a tunable C0~ laser
to excite the Molecule at several frequencies and fluence levels. Neat samples
were used at a to ta l pressure in the range 10"^-10"^ Torr. Detection and ident i -
f i ca t ion of the products as well as re la t ive y ie ld determinations wera accomp-
lished usinn photoionization in a time of f l i g h t mass spectrometer. The ohoto-
ionization l i j h t source was a VUV laser operated at 10.47 eV (D. Feldnann, J .
Laukenper and K.H. Welge, J. Che»i. ?hys. 79, 278 (1983)), providing 10"8 sec
time resolut ion. In the absence of the infrared laser radiat ion, only the parent
ion peak was ohserved. Gradual increase 0* I * laser fluence led to the appearance
of several smaller ions, the smallest Mass being n/z = 18 and" 15 (CD3 and CM3").
,'!any of the f r a g w i t s s.rn assi~re^ to dissociat ive ionizat ion of v ibrat ional ly
excited Darent molecules. Methyl ions are forned sy d i rec t photoionization of
methyl radicals produced by neutral dissociat ion. This conclusion is based on
the absence of CHg ions in the IRMPD of the parent ion ( in contrast to the pre-
sence of a l l other fragments) and to i t s absence in the photoionization of the
parent molecule with photon energies up to 14 eV. In a l l cases' studied the pro-
tonated an<i deuterated fragments appeared simultaneously and in equal amounts
showing that no preferent ia l produce could be induced uoon i n i t i a l exci tat ion of
bands associated with e i ther the CH- or t!ie CO, groups. This resul t shows that
intramolecular energy transfer in th is molecule is fast compared to simple bond
f iss ion on the t ine scale of the infrared multiphoton exci tat ion process M O " 7
seconds).
67
,' . TC7
VIBRATIONAL ENERGY DISTRIBUTIONS FOLLOWING INFRARED MULTIPHOTOH EXCITATION
S. RUHMAN, 0. ANNER, Y. HAASDepartment of Physical Chemistry and The F r i t z Haber Research Center fo rMolecular Dynamics, The Hebrew University of Jerusalem, Jerusalem, Israel
In th is study pa r t i a l v ibra t iona l energy d is t r ibu t ions fo l lowing C0« laser mul-
t iphoton exc i ta t ion (MPE) are determined. This is achieved by comparing chemi-
luroinescence signals from the unimolecular decomposition of tetramethyl dioxe-
tane ("TOD) fo l lowing ;1PE, to those recorded a f te r sinole photon overtone exc i -
ta t ion (OTE) in which 3, 4 or 5 v ibrat ional quanta of t i e C-'', stretching node
are exci ted. The analysis is based on two assumptions: 1) T:iat energy redis-
t r i bu t i on in TMD is mucn faster than the molecular decomposition so that tne
energy content is the sole factor governing the k inet ics of dissociat ion and
subsequent luminescence; 2) That the re la t i ve l y broad snergy d is t r ibu t ion of
molecules excited by iiPE above the reaction threshold can be adequately approxi-
mated by a superposition of the narrow energy d is t r ibu t ions resul t ing from ab-
sorption of 3, 4 and 5 C-H stretch quanta. The v a l i d i t y of these approximations
is discussed in the paper.
Vibrat ional energy d is t r ibu t ions are arr ived a t in the fol lowing way: A compu-
ter optimisation routine calculates a superposition of the three emission s i g -
nals resul t ing frow OTE to V-3, 4 and 5 to best f i t the MPE signal under study.
The coef f ic ients o f th is superposition represent the energy d i s t r i bu t ion of
those molecules excited beyond threshold. Using accepted approxinations of "OTZ
cross-sections fo r absorption we detemine aosolute y ie lds of exc i ta t ion beyond
threshold upon MPE. The simultaneous knowledge of exc i ta t ion y ie lds plus d is -
t r i bu t i on of energy in real time leads through the use of computer modelling to
an improved descript ion of the dependence of a(E), the energy deoendent cross
sect ion, on the in ternal energy.
68
TC8
PREPARATION AND SPEaRAL ANALYSIS OF BACTERIOCHLOROPHYLL DIMERS IN VITRO
BY AN EXTENDED VERSION OF EXCITONIC INTERACTIONS
A. SCHERZ, W.W. PARSON*Biochemistry Department, Weizmann Institute of Science, Rehovot 76100, israel
*Department of Biochemistry, University of Washington, Seattle, Washington, USA
Qilorophyils and bacteriochlorophylls, serve as energy collectors and electron carriers in
green plants and photosynthetic bacteria. The pigments generally are bound to proteins as
complexes that contain from two to six molecules of chlorophyll or bacreriochlorophyil together
with their free-base analogues, The absorption spectra of these complexes differ sig-ificantly
from the spectra of the monomeric pigments in_ vitro. The lowest lying (Qy) absorption band
is shifted to longer wavelength and in some cases has a substantially larger oscillator strength
and rotational strength. The four bacteriochlorophylls in reaction centers of Rhodopseudomonas
sphaeroids, for example have absorption bands at 800 and 865 nm, compared to 775-780 nm
for BChl in organic solvents Also, the combined dipole strength for the in vivo Qy transition
is 64 debye^ versus 39 debye per 1 BChl, The origin for the differences is important because
they probably reflect the setting which enables bacteriochlorophyll and chlorophyll, to be
universal electron donors: Recently, we isolated relatively woll defined dimers and higher
oligomers of bacteriochlorophyll and bacteriopheophytin. The procedure involves trapping of
a desired number of chromophores in large micelles of LDAO (Lauryl dimethylamine oxide),
aftei which a careful study of the spectral changes through the conversion of monomer to dimer
was possible. We could observe a decrease of oscillator strength in the VIS-U,V, region (hypo-
chromisrr.) compensated by ao absorption i.-crease in the n.i.r, (hyperchromism). A great increase
of optical activity with non conservative individual elements could be seen. The simultaneous
changes in nor degenerate transitions pointed to mixing of various states via dipolar interac-
tions. We therefore evaluated the ground and excited states of the dimers in terms of pertur-
bation !heory where, to the zero order function that result from excitonic interaction between
Jegenerare states, first order perturbation of non degenerate states was added. For example,
the lower most transition of the dimer was shown to have some contribution of the monomeric
By transition. These effects enhanced the inspected strength of the absorption and the optical
activity in the n.i.r. region. The theory accounts quantitatively to most of the spectral pro-
perties of chlorophyll and bacteriochlorophyll aggregates in vivo and in_ vitro and may lead
to reevaluation of some data concerning with primary electron donation in photosynthesis
69
iT9
PHOTOINDUCED ELECTRON TRANSFER REACTION IN ORGANIZED ENVIRONMENTS AS
PHOTOSYXTHETIC MODELS
Y. DEGAXI, n. MANDLER and I. JVILLNER
Department of Organic Chemistry, The Hebrew University of Jerusalem, Israel
Photosensitized electron transfer reactions ;iro of interest as a means of
mimicking natural processes such as c'O-, and N, fixation processes. We have
examined photosensitized electron transfer reactions in interfacial systems
such as charged colloids , water-in-oil microemulsions" and vesicles . By
proper design of the electric hydi'ophobie properties of the components effec-
tive quenching and charge separation of the photoproduets has been achieved.
Using DQS", (1_) as electron acceptor, effective separation of tho photoproduct.
DQS7 from the oxidized species, Rufbipyll , is accomplished in the SiO,
colloid (eq. 1). The subsequent catalysed hydrogen evolution by DQS- ivas -ilso
demonstrated.
Ru(bipy): + DQS" SiO DQST
The photosensitized cleavage of acetylene fHCiCH) to methane has been accomp-
lished as a model for the nitrogen fixation cycle. In this system Ru(bipy)I+
acts as a sensitizer, [Ru(NH-)_Cl]~ acts as a catalyst for acetylene fixation,
and triethanolamine is the recycling electron donor of the system (eq. 2).
Similarly, enzymes have been introduced as catalysts in photosensitized
electron transfer cycles leading to the reduction of ketones to alcohols.
hvHC=CH + 6H 6e 2CH, (.2)
1. Y. Degani and I. Willner, J. Amer. Chem. Soc, 105., 6228 (1983).
2. D. Mandler, Y. Degani and I.Willner, J. Phys. Chem., in press (1934).
3. I. Willner and Y. Degani, J. Chem. Soc. Chem. Commun., 1249 (1982).
70
TC10
FORMATION OF MULTI-ELECTRON REDUCTANTS vi£ INDUCED DISPROPORTIONATION OF
SINGLE ELECTRON TRANSFER PRODUCTS
Reuven MAIDAN, Zafrir GOREN and Itamar WILLNER
Department of Organic Chemistry, Hebrew University of Jerusalem, Jerusalem,
Israel.
The disproportionation equilibrium of a single electron transfer product, A*,
lies overwhelmingly towards the one electron reduced species in a homogeneous
phase. Nevertheless, by designing opposite solubility properties of the
disproportionation products, A" and A"' , in water-oil phases, this equilibrium
can be shifted towards the two electron reduced product.
2A t« * A: + A2+ (1)
We have found that dioctylbipyridinium radical cation C V-, i_, undergoes an
induced disproportionation reaction in an organic-water two phase system
(eq. 2). This process is a result of the opposite solubility properties of
C R V and CnV" in the two phases. The disproportionation equilibrium constants
in the two phase system have been determined by spectroscopic means.
(2)
The two electron reductant, CgV" , has been utilized in debromination of 1,2
and l,]-dibromc substrates (i.e. Jibromostilbenc and benral bi'omide). The
functions of C OV in these .debromination reactions have been verified bv evelico *
voltammctry. Photoinduced elec':.ron transfer reactions followed by the
disproportionation process were designed as models for photochemical multi-
eJectron reduction processes in nature.
1. Z. Goren and I. (Villner, J. Amer. Chem. Soc, in press (198?)
71
TC11• THE DECAY OF THE NITROBENZENE AMI ON RADICAL (N8--) IN AQUEOUS SOLUTIONS
CONTAINING Pt COLLOIDS (Ptc). A PULSE RADIOLYTIC STUDY
G.S. NAHOR, J . RABANI
Energy Research Center and Dept. of Physical Chemistry, Tne Hebrew Universityof Jerusalem, Jerusalem 91904, Israel
In a previous study (1 ) , we havo reported that Nitrobenzene is capable of func-
t ioning as an electron acceptor in a photochemical system in which t e t ra - ( su l -
fonato phenyl) Porphyrin (TPPS1*") is excited by v is ib le l i g h t . The products of
t i l ls process were N3'- and TPPS3". In order to cneck tne importance of such a
system to photocnenical cleavage of water we wished to Jctonrins ^het.ier 'IS--
is capable of t ransferr ing an electron to ?t co l lo ids , wnic; ara .-/ell known as
catalysts for reduction nf water to hydrogen.
Tne pulse radiolysis technique was used to generate -JB--. ~n.n aasnrotion o-f
whicn was followed at 313 nn aid 355 n<n (E = 3000 M " ' c n " - *ni 5*0 ""1cn"- re-
spect ively). The "IB concentration was 4x10"^ " and t,ie concentrations of '•'<->•-
produced by tne pulse were 1.3xlO"5 '1 for pulse duration of 0.5 and 3.1xl3"5 ''
fo r pulse duration of 1.3 ysec.
At pH = 3.2, :I3- .vas produced within a few picroseconds and in the absence ov
Ptc i t decayed away in a single second order process, k = 6xlO3 " " - s " 1 . Tnes°
findinns are in agreement witn previously reported data (2). In the presence of i
Ptc, a sinnle f i r s t order process was observed. This process was also - i r s t or-
der with respect to fPtc ] . Tne second order rate constant was k = (3 .5-1. n )x l0"
i ' " ^ " 1 . This dependence on [Ptc] d i f fe rs from tne observation in tns '•'''• + .'.-tc
system where Higher order in [Ptc] was found (3). i<e a t t r ibu te th is to a some-
what d i f ferent mechanism.
We have also shown tnat the system N3«-/Ptc/Hz is in equi l ior ium. This .-/as done
by bubblinn H2 through a solution o^ N3, upon i n t roduc i i " small amounts c f Ptc
the yellow colour of 'J3-- immediately appeared.
Acknowledgement: This research was supported oy the Soireiber coundatinn and uy
the National Council for Research and Development.
References:
(1) G.S. Nalior, J. Rabani, F. Crieser, J . Phys. Cnen. 85. 597 (1981)
(2) K.-D. Asnus, A. i/igger, A. Hennlein, Ber. Bunsenges. Phys. Che'n. 7£_,
" i (3) l1. Brandeys, G.S. Nahor, J . Rabani, J. Phys. Chem., in press
72
TD1
2-THIA-l,3-DIAZETIDINE-2-OXIDES: ZWITTERIONIC FOUR-MEMBERED SULFENIC ACIDS Z
U. ZOLLER and P. RONADivision of Chemical Studies, Haifa University-Oranim,
P.O. Kiryat Tivon, 36910, Israel.
Little is known about for-membered hetrocycles containing the -N-SO-N- array as
part of the ring (i.e. 1) .
1 2i 4
1
We have investigated the 2+2 cycloaddition between Schiff bases and N-sulfinyla-
mines as a promising route for the synthesis of 1_. Specifically, benzalamines
{2J were allowed to react with N-sulfinylamines (3) to yield, after work up,
either the expected four-membered heterocyclic system 1_ or its rearranged and
cycloaddition products depending on the substitution pattern of the reacting
Schiff bases: r-R_ - N — S O :
R - N = CH - C.H. + R_ -N = S = 0I b o Z
- CH = N-C
j c^CH-N-RjI- l J
a. R. = C,H. a. R. = C,H. OH1 6 5 2 6 D |
c. R ] = p-CH3-C6H4 c. R2 = p-CH3-C6H4 ^ _ , . A + \ ; , _ R ^
d' Rl = C2H5 \ - /CJ
5 a-c
The four-membered ring system 5 constitutes a remarkably interesting new class
of compounds which may be considered as a stable cyclic sulfenic acid and a
mesoionic heterocycle - simultaneously. The synthesis and the mechanisms of
the formation of £ and 5_ will be discussed followed by the presentation ofr •
selected results concerning the properties and chemistry of the later.
/
• • T D 2
\ COBALT COMPLEXES OF THE TYPE LjCoR
S. CHOCRON*, R. MOHTACHEMI**, H. SCHUMANN** and M. MICHMAN*
•Institute of Chemistry, The Hebrew University, Jerusalem, Israel.
**Institute for Inorganic Chemistry, The Technical University of Berlin.
Several methods of preparation of cobalt alkyl complexes have been
studied. The cobalt compounds are of the type L-CoR where L = Ph-P:
Ph,CH,P; Ph(CH_),P; Ph.As: Ph^PGe(CIL),; Ph^PSn(CH_),; R = CH. and
with the first two ligands R = Si(Cll_). as well. Some aspects of the
reactivity of these compounds e.g. in oxidative addition reactions have been
studied as well.
74
TD3
A MECHANISTIC STUDY IN THE THERMAL ACID-CATALYSED REARRANGEMENT OF
TRANS METHYL CHRYSANTHEMATE TO LAVANDULYL DERIVATIVES
Z . GOLDSCHMIDT*, B . CRAMMER*, R. IRAN*** Dept. of Chemistry, Bar-Han University, Ramat Gan 52100, Israel** Dept. of Organic Chemistry, Hebrew University of Jerusalem, Jerusalem 91904,
Israel
Treatment of trans methyl chrysanthemate (1) with 50% aqueous sulphuric acid at
room temperature initially rearranged to equal amounts of methyl lavjm.dulyl
esters; methyl trans-5-methyl~2-(2-propenyl)-S-hexenoate (2/ and methyl zranc-
c-r>,etKyl-l~(2~nydroxy-2-propyl)-3-nexenoate (3; wnich were former t ;• a
*yclopropylcarbinyl-homoallyl rearrangement. The B-hydroxy r.e-.hy' l.ivandul:-l
ester IS, undergoes both dehydration to the conjugate ester, methyl trane-t-
meihyl-i- 1-V}>opy1idcae 'S-hexenoate (4* and a retrograde alaol clc^oage to
methyl Z!'-inp-c-me4'i..-l-?-hexenoat£.. The non-aon,juaate ester- (*,. alei isorierisej
ic its .-.'.—oDr.jugaia counterpart (L). Similar acidic conditions on the lavandulyl
"ttar^rc ". a\d c • each gave a mixture of -lavandulyl methyl esters and il/.Under
aeuzera:•:s conditions only the isopropenyl sidechain of (1) was deuterated. This
u'as also chserved for the isopropenyl moiety of the rearranged lavandulyl methyl
asters. Fro-, these results a rr,eahanis>'. is postulated of the formatio>: ~f 'r.et'nyl
o.rjandul-' esters fror. Hi. At lZC'^C a mixture of unsaturated y- and 6-lactonee
•;<is obr.:ii,KcJ from (1, in similar acidic conditions. The principal lactone :;as
':,L-.:ii.ii;»-—i-(2-pyopijl'-?-(2-propylidene)-2{ZR]-furc.no>ie (C'.The fact that only
; , ' m r < v icrivativc? i'ure obtained may shed new light or the biogenesio of
H
R.T.
COOCH-
(1 )
COOCH.
(3)
130°CCOOCH3
( 4 )
COOCH.
( 5 )
( 6 )
75;
TD4
CHARACTERIZATION AND GEO-ORGANIC SIGNIFICANCE OF OXIDATION PRODUCTS OF
MELANOIDINS.
Y. RUBINSZTAIN, P.IOSELIS and R. IKAN
Department of Organic Chemistry, Hebrew University of Jerusalem, Jerusalem 91904,
S. MORINAGA and R. ISHIKATARI, Department of Chemistry, Tokyo Metropolitan
University, Setagaya-Ku, Tokyo, Japan 158.
Humic substances are probably the most widely distributed natural products
occurring in soils, lakes, rivers and sea. They are amorphous polymer-like
substances of molecular weight ranging from several hundred to tens of thousands.
Marine humic substances (humic and fulvic acids i have been suggested to be
derived from sugar-amino acid condensation. The objectives of this investigation
were to synthesize a series of melanoidins and to compare their physical and
chemical properties with natural humics. In this presentation we report the
results obtained by permanganate oxidation of melanoidins. The main products
identified by GC and GC/MS include a series of aliphatic mono- and di-carboxyii.:
acids and benzene carboxylic acids. Some of these acids were essentially the
same as those produced by permanganate oxidation of humic and fulvic acids.
The possible routes leading to the formation of the oxidation products of the
melanoidins and the geo-organic significance of these findings will be presented.
76
TIG
SYNTHESIS AND BIOLOGICAL ACTIVITY 0! "LiTANOLIDES
V. WEINSTEIN and R. IKAN, Department of Organic Chemistry, Hebrew University
of Jerusalem, Jerusalem 91904, Israel
H. SPIGELSTEIN and A. HALEVY, Department of Ornamental Horticulture, Faculty of
Agriculture, Hebrew University, Rehovot.
A series of nono- and disubstituted y-lactones (butanolides! were prepared from
optically actiw aiTiir.c acids. The cr.ar.tioraevic purity :*f the butanclides \:a?
confirmed by NMR using PirkK-'s solvatiag reagent and hy X-ray structural
analysis. It was found that certain compounds possess pleasant odors as well
as plant-growth promoting and inhibiting activity. A correlation between the
structure of the butanolides (number, position and character of t::-.- substituents.i
and their biological activity was found. The butanoiidos were synthesired
according to the following routes:
COOil
NH,
(S')-(+)-Gjutamie Acid
steps
COOH Kl
COR
C0011
R - alkvl
COOH«,=!!: CONR,il.; Cll,; COOR,
77
TD6
PEPTIDE SYNTHESIS WITH INS0LU3LE POLYMERIC REAGENTS:
THE USE OF A SOLUBLE ACYL CARRIER ("SHADCHAN"^).
Y. SHAI and A. PATCHORNIK,
Dept. of Organic Chemistry, Weizmann Ins t i tu te of Science, Rehovot, I s rae l .
Multiphase polymer system have been used more fo r mecnanistic studies than for
synthesis. A novel approach fo r peptide synthesis is based on a two-polymer
system and a c i rcu la t ing car r ie r ("Shadchan"). A greatly s impl i f ied schematic
drawing of tne system is shown in Fig. 1.
X
Polymer I carries an N-protected ami no acid which is bound as an active ester.Polymer I I is a Merrifield-type polymer carrying an anino acid or pentide whosefree carboxyl terninal is Dound as "benzyl" ester to tha polymer.The soluble carrier, a, is a compound capable of preserving the free energy ofan active ester (imidazole, 1-hydroxybenzotriazole, etc.). The UV cells providecontinuous monitoring of the reaction's progress by comparing the optical densi-ties of solutions entering and leaving compartment I I .
Using this approacn we nave synthesized a few short peptides as v/ell as a pro-tected derivative of leu-enkephalin in high yield and 99% purity (HPLC, aninoacid analysis).The "Shadcnan" principle, as described for peptide synthesis, has general appli-cabi l i ty for the coupling of two species by displacement (equations 1,2).
(1) © -a' - A + a + 0 - a ' + aA
(2) © -B + aA •+ (rt) -B - A + a
Additional applications of the "Shadcnan" method were demonstrated in other ba-sic reactions, such as acylation, phosphorylation, bromination and deuteration.
* "Shadchan" the Hebrew term for a matchmaker, go between or agent.
o may or may not L»e chemically iden-tical to a1.
78
TD7
POLYMERIC 4-ALKYLAMINOPYRIDINIUM SPECIES AS STABLE ACY. TRANSFER REAGENTS
K.A. JAC03S0N and A. PATCHORNIK, Dept. of Organic Chemistry, Weizmann
Institute of Science, Rehovot, Israel.
Two polymers containing immobilized 4-dimethylaminopyridine derivativesx ' '
were converted into stable, polymer-bound l-acyl-4-alkylaminopyridinium chloride
salts. I t was demonstrated that the acyl group is highly reactive towards
amines and thiols and, to a lesser degree, towards alcohols, effecting acyiation
without the need for addition of base. With carboxylic acids, symmetric or mixed
anhydrides are formed. Similarly, phosphoryl and sulfonyl groups have been
immobilized as the reactive 4-alkylaminopyridinium salts which were used in
synthesis. The acyl group may be transferred from the polymer in a soluble
reactive form upon treatment with imidazole; thus, the polymeric acyl
pyridinium species is proposed as a "bank" in the shadchan method of synthesis
using multi-polymeric systems and a circulating solvent * .
RCOC1 (PJ-CM R'UHX»RCOHHR' + I
I R-C=G~
1. A. Hassner, L.R. Krepski, and V. Alexanian, Tetrahedron 1970, 34, 2069.
2. G. Ho f le , U. S tog l ich , H. Vorbruggen, Angew. Chem, I n t . Ed_. En^l. IVB 17,
569-583.
3. Y. Shai , and A. Patchornik, see preceding paper.
79
TD8
PREPARATION OF ACYL HALIDES OR ANHYDRIDES UNDER MILD AND NEUTRAL CONDITIONS,
USING POLYMERIC REAGENTS.
M. AVRAMOFF, A. PATCHORNIK ,Dept. of Organic Chemistry, Weizmann Institute of
Science, Rehovot, Israel .
a-Haloenamines, generated by treatment of irninium halides with ter t iary (amines, readily transform carboxylic acids into acyl halides*. We have
extended the u t i l i t y of this reaction with the aid of reusable polymer-bound
reagents, this fac i l i ta t ing recovery of reaction products.
Chloromethylated polystyrene was transformed into the N-methyl derivative and
subsequently acylated with isobutyryl chloride The resulting polymeric
secondary amide ( I ) was transformed into the quaternary iminium chloride ( I I ) .
Acyl halides were prepared directly from I I by addition of triethylammonium
salts of carboxylic acids; most l ikely I I I is the active reagent. The halides
could be either isolated by d is t i l la t ion or as their anilides in the reaction
mixture. The reaction of I I with two equivalents of the carboxylate salts
provided carboxylic anhydrides in place of acyl halides.
-ay/ (PJ-CHON' /P)-CH.1 vCOCHMe2
d *C-CHMe2 ^ c
i ii c\ in ii
1. A. Devos, J . Retnion, A.M. Frisque-Hesbain, A. Colens, L. Ghosez,
J.C.S. Chem. Comm., 1979, 1180.
80
TD9
INTRAMOLECULAR PHOTOACYLATION REACTION IN BIPHGNYL SYSTEMS
I . SHAPIRA-COHEN, A. SHANI, A. PAROLADepartment o f Chemistry, Ben-Gurion Univers i ty o f the Negev,Be 'er Sheva 84120, I s r a e l
The intramolecular p h o t o c y c l i z a t i o n of biphenyl system(I) to y i e l d lactone II was
studied:
OCYK _ ^ A ^ ^ / ; + R O H / R W I 2
\
\ = Mi; R - C,H., n-C,H Cll , C;H , p-C
The effects of the leaving group Y-R, the solvent and t r ip l e t sensi t i -er have
been examined. In general, the carbonates 0=0) gave higher yield of 11 than
the carbamates (Y=\H\ and phenyl-O-o-biphenylyl carbonate (R-C IL ,IT11 gave
Mic highest (SS"o in methanol). Tt set-ins that the more acidic the conjugated
acid L'f the leaving groun i-~, the more efficient photocycii ration takes place.
II.'.' .stcric effect shewed that the l,;r;..'cr a;.d bulkier groups rave lower yjelti of
the lactone. Parallel reaction to the slow photucyclination of the carbamates; 7
to yield II was the photolysis to afford hinhenyl ":': ver>' iou yield. The
reaction was carried out in 4 different solvents - mcthanol, dioxane, te r t -
htitanol and; toluene. It was found, that generally, the. more polar solvent used,
the more efficient the photocyclization was , except for a fen exceptions. Aceto-
phenone as t r ip le t sens i t i : c r enhanced the reaction both of the carbonates and
*he carbamates, while hiphenyl formation was slowed down. A model, based on
molecular orbital considerations,supported the proposed mechanise cf the photo-
cyclization.
81
TD10
OXIDATION OF DERIVATIVES OF ASCORBIC ACID WITH
SUPEROXIDE ANION RADICAL (0^) IN APROTIC MEDIA
A.M. FRIMER, P. GILINSKY-SHARONDepartment of Chemistry, Bar-Ilan University, Ramat-Gan 52100, Israel
Of the various roles played by Ascorbic Acid (Vitamin C, \ : R-j = R2 = H ;R, = CHOH—CKpOH) in plants and animals, perhaps the most notable is that ofantioxidant. On the other hand, 0" , formed in aerobic organisms during themetabolism of oxygen, is a ready source of oxidizing free radicals. Hence,we explored the reaction of various ascorbic acid derivatives (la-d) with Q~. ,generated in aprotic media via the complexation of KO2 with 18-crown-b. Re-ductones ^ and U> yielded the corresponding esters subsequent to CH-.I workup,while j3 was the sole product obtained from jc. Enol ether )d undergoes elim-ination producing, as the only isoiable product, 4d which was identified asthe corresponding acetate. Results from other laboratories and tiie questionof mechanism will be discussed.
b:
d:
1
— L I « D —
* 3
— LJ • D * r u— n j rv« wn
» H; R2 « CH 3 ; R3
« R2 = C H 3 ; R3 =
30% 60%
80f*
82
TD11
/* TtfO-STtP hldH YIELD SYHTritSIS OF2-0XA-3-0X0-A4 STEROIDS
A.A. FRIMtR, J. HANEIRIOept. of Chemistry, Bar-IIan University, Ramat-Gan 52100, Israel
A variety of heterosteroids have been synthesized in the hope that the bene-
f ic ia l effects of steroidal hormones could be separated from the prevalentundesired effects. Some success has been reported in the case of 2-oxa-
43-oxo-A -steroids, though a facile high yield synthesis has been lacking.
We have devised a high yield two-step process Involving ttie t-butoxic!e
mediated autoxidation of the corresponding parent compound (methylene analog).
As shown below, the kinetic enolate is generated and oxygenated at - 7b°C in
aprotic media resulting in enol £. The reaction mixture is then wanned to room
temperature and the enol autoxidizes further to lactol ^. Sodium boronydride
reduction of tne lactol produces the desired oxasteroid 4 in overall yields4approaching a'o% in the case of A -cholestenone and testosterone.
t-duOK/lo-crown-
*:
HO
,, toluene, -73 C tf
^References i!
1. R. Pappo, Intra-Science Chemistry Reports, 2, 105 (1969).Z. H. Singh, V.K. Kapoor, and D. Paul, Prog. Med. Chem., 1^, 35 (1979).
83
c TD12
RIHG CLEAVAGE OF SUBSTITUTED IMIDAZOLES - A NEW ROUTE TO THE SYNTHESIS
OF BIFUNCTIOHAL CHEIATIMG AGENTS FOR RADIOLABELLING AND TUMOR IMAGING.
JAMZNA ALTHAN* NORXT SHOEF** HEIR WILCHEK* and ABRAHAM WARSHAWSKT**
** Department of Organic Chemistry and 'Biophysics, Weijt*ann Institute ofScience, Rehovot, Israel.
Bifunctional chelating agents, of the class of ethylenediaminetetra-acetic acid
(EDTA) analogues, first introduced by Meares and coworkers1, make possible use
of metal radioisotopss for radiolabelling and tumor imaging and attract great
attention?'3 The common way to EDTA analogue synthesis has been through re-
duction of the appropriate aminonitrile or amide, and subsequent alkylation with
bromoacetic acid.
In this conmunication, a new approach to EDTA analogues, based on Bamberger ring
cleavage dibenzoylation of suitable substituted imidazoles under Schotten-Baumann
reaction conditions, reduction and hydrolysis"to vicinal diamine system and
alkylation, is described. '
"lC°\H
HC—CH» > . _/ 2J-P
CHIXP
7—*"2 m. HC-Crt,(cm)_ y . *?H2}n (CH2)n ^CCHTI
X*CO 2 - ; -NH-
XP
P* Protecting group w
1. M.W. sundberg, C.F. Meares, D.A. Goodwin and C.I. Diamanti, J. Med. Cham..17, 1304 (1974).
2. W.C. Eckelman, C.H. Paik and R.C. Reba, Cancer Res., 40, 3036 (1980).
3. R. Rainsbury and J. Westwood, The Lancet, 1347 (1982).
4. J. Altman, N. Shoef, M. Wilchek and A. Warshawsky, J. Cham. Soc. PerkinTrans I. 365 (1983).
84
TD13
SYNTHETIC APPLICATIONS OF THE CARBANION WALK MECHANISM:
A NOVEL PREPARATION OF 1,3-DIMETHYLENECYCLOBUTANES.
S. BRAVERMAN*. M. FREUHD*. I . GOLDBERG***0ept. of Chemistry, Bar-I lan Universi ty, Ramat-Gan, Israel
**Dept. of Chemistry, Tel-Aviv Universi ty, Tel-Aviv, Israel
Recently, we have reported a novel base-catalyzed cyclodimerization of d ia l leny l
sulfones to 2,6-dithiaadamantane 2,2,6,6-tetraoxide der ivat ives, and explained
the i r formation by a "carbanion walk mechanism", in which an a l l erne a-sulfonyl
carbanion in i t ia tes, a series, of four consecutive inter- intramolecular Michael
addit ions, with f ina l return of the negative charge to i t s or ig inal carbon.
Subsequently, we have tested th is mechanism on monoallenic sulfones, and have
shown that treatment of Y,Y-dimethylallenyl phenyl sulfone (]_) with rv-BuLi under
the same conditions (THF, 0°C) led to vinylal lene Z_, while i f the same reaction
is run at re f lux temperature, the expected cyclodimer 2 can be obtained, but
only as a mixture with i t s precursor i . Surpr is ingly, we have now found that
i f sulfone 1_ is f i r s t treated with one equivalent of j i -BuLi, and next with one
equivalent of sulfone ^ , both at -78° , the only product observed is the 1,3-
dimethylenecyclobutane derivat ive 5_. Unequivocal structure proof of compound
£ was obtained by X-ray crystal 1ographic analysis, which also shows the two
sulfonyl groups in a trans conf igurat ion. The results may be explained in terms
of the re la t ive s t a b i l i t i e s of the corresponding vinyl allene carbanions. This
novel and convenient approach to the synthesis of 1,3-dimethylenecyclobutanes
nicely complements the thermal cyclodimerization of allenes to 1,2-dimethylene-
cyclobutanes, a reaction of long-standing in teres t .
Z
1 R « K i. R • H ' 1 R • H
1 "« ' * Z - PhS^ i R - Me
I . ^. uravtraan, D. Reisman, M.| Spree her, jii. Rabinovich and F. Frolow,T«trah*dron Lttters, 901 (1979). •'/'
j i97j i
85
TD14
A NEW HALOGENATION REAGENT SYSTEM:
POTASSIUM HALIDE/18-CROWN-6/OXIDANT
M. SREBNIK, R. MECHOULAMHebrew University, Pharmacy School
A mixture of potassium halide (Br~, Cl", or I ) and crown ether,
18-C-6, in CHC1, when titrated with p-chloroperbenzoic acid represents
a new, facile, high yield, regiospecific halogenation reagent system.
A few examples: •, ;;
Aromatic bromination A
OMe
OMe COCH.
Addition to double bond
OMe
OMe
Br
OCOC,H.C16 4
:OCH.
6 4
Cyclization and lactonization
HO
R«H2 or 0
.36
• " " — ' , " \ \ ~ " • " • " • • " • — • '
Til l 5
THE ADDITION OF CARBOXYLIC ACIDS TO ALKYNES USING RUTHENIUM CATALYSTS
Y. SHVO and M. ROTEM
Department of Chemistry, Tel-Aviv University, Tel-Aviv 69978, Israel
Ru3(C0)12 **as found to function as a catalyst precursor for the addition of
carboxylic' acids to alkynes. The reaction which yields vinyl esters is exempli-
fied below with acetic acid and diphenylacetylene; a rearranged product, 2,2-
diphenylvinyl acetate (91) is also formed.
Ru,(C0)19CH3CO2H + PhCmCPh i " » PhCH»C(OAc)Ph + Ph£C =C(OAc)H
1 4 0 ° (E)-82%; (Z)-9% 9%
Straight and branched chain carboxylic acids, including pivalic acid, as well
as benzoic and substituted benzoic acids, behave similarly. Dimethyl acetyl-
enedicarboxylate, 4-oxtyne and phenylacetylene also react in the same manner.
The lat ter , an unsymmetrical alkyne, yields mainly (77%)-3-acetoxystilbene, an
anti-Markovnikov addition product. ^Conversions of 55-96% were encountered with
the various starting materials. Appropriate control experiments were carried
out. The E-isomer which results from a cj£ addition to the tr iple bond is the
kinetically controlled product. The normal vinyl esters are not precursors of
the rearranged vinyl ester.
The chemistry of Ru3(CO)^2 w i t h benzoic acid was found to differ from that witA
acetic acid. Three complexes were isolated: [Ru(C0)2(PhC02)]2,[Ru(C0)3(PHC02)]2
and [Ru(C0)2(PhC02)(PhC02H)]2; a l l are reactive in the addition reaction.
The scope and mechanism of this new reaction of R I L ( C 0 ) 1 2 as well as the struc-
ture and chemistry of the above complexes wil l be discussed.
87
"• i
; TO16
• CPYPTALLOORAPKTC STTIEIfP OF srv? SiOLECTLA" COKPLFXrT
i
I F.H. mPBSTRin, r. v'APcr, G ." . PFTP'TF, : \ r.. w°zr.,
J Dept. of Chenistry, Technion-Tsrael Institute of Technolopy,Haifa, Israel 5P0OO.
Crystal s t ructures are reported for the molecular complexes of ?WY with
chloroform, jn-dinitrobenzene and jj-dimethylsriinobenznldehvde. All three
; complexes ( f i r s t reported by T.M. Veilbron an* ,7.P. "ucV- (J . Chem. Poc. 11V,
| 1R0O (1Q?1V have nui+e d i f ferent s truntures . Tr PKDK'O. ?'f2T ( * r i c l i r i c , "«*>,
Pl^ the host nolecwles are. linked by two hydroxvl-carbony" ^y^rorfn bonrts +o
f o m rer.trosynitietrie pn irs , i»it*i the 'lisorrterei f!!ri.. mol^culns oor.t^iner i i
c a v i t i e s l e f t between the molecule p a i r s . mhe comrlpx i s e c l a t h r a t e . In DH K*
m-dinitrobenzene ( t r i c l i r i r , ?."A, Fl) the ^Ff" raoienules nre HnVeH ir ribbor.K
through head-to-waist, hydroryl-carbonyl hydropen bonds. The puest molecules arc
contained in sinuous channels l e f t between the DHDK ribbons; the host nnd puest
molecules are e s s e n t i a l l y coplanar. Rucoesssive planes are mutually sh i f ted so
that, the «?uest molecules are enclosed above nn.i below by host no l eou le s . This i s
a new s tructura l type, with features reaemblinp those of channel inc lus ion
complexes. In DF!5K«j>-dimeth.yl»minobenzaldehyde (monoclinic , 7«4, T2^/n) the hos^
molecules are arrp.need so as to leave channels of approximately rectanpular
c r o s s - s e c t i o n in which the jmest molecules are accommodated. mherp ip hydrorer
bonding between host hydroxyl and puest carbonyl proups but host -host
i n t e r a c t i o n s are due only to dispersion and d i r o l e - d i p o l e forces . mhis i s p.
channel - inc lus ion comTslex. In the chloroform and jj-dimethylaninobenzaldehyde
complexes the host molecule has the a-trar.s, trans oonformat.ion but in the
jn-dinitrobensene complex i t s conformation i s s - c i s , trans .
88
Tin 7
MORPHOLOGY OF ORGANIC CRYSTALS 2V ENERGY CALCULATIONS
: Z. berkovitch-Yellin and L. Leiserowitz
; Dept. of Structural Cheaistry
' Weizmann Institute of Science, Rehnvot Israel
The morphology of a growing crvstal is directly related to the relative
growth rates of its faces, with the general rule that those faces whirh
grow slower appear as larrer faces. A controllinr factor in crystal growth
is the energy of the interactions between neighboring Molecules. The
; crucial relationship is between the layer energy - which measures the
' stability of a layer parallel to a face (hkl) and the attachment energy -
I whicu is related to the growth rat« perpendicular to this face.
f Thi* taeorctical form of organic crystals was studied by *;2ans of aton-aton
potential energy calculations. The effect of "tailor-made" additives on the
morphology was studied by substituting substrate molecules at various
( crystal surface sites with an impurity. The theoretical results were
, compared with experimental morphologies of crystals grown in the absence
and in the presence of the same additives. In those cases where there was
a discrepancy between the calculated and observed morphologies, the
deviation could be explained by preferential adsorption of solvent molecules
* at specific faces of the crystal. The potential energy at closest approach
distances of various crystal faces was mapped and orovided an explanation
for this prediction.
89
TD1 -'
A SIMPLE NETHOO FOR THE ESTERIFICATION OF FATTY ACIDS
H. WIENER , A. 1ANIEL and C. GILON* )
Tlw Casali Institute of Applied Chemistry and*Depart*ent of Organic Chemistry,
; The Hebrew University of Jerusalem, Jerusalem 91904, Israel
• 4-Dimethylamimopyridinol (DHAP) was found to be a super catalyst for
acylatiom amd alkylation reactions. (1) A complete conversion of caxboxylic
acids into their esters was achieved by a one pot reaction using dicyclohexyl-
carbodiimidc (DCC) as the coupling agent and DMAP as catalyst (2). When the
• esterification of fatty acids (c12"
C20-' witn t-DUtano1 Kas performed underI these conditions (2) the major product was the undesired N-acyl dicyclohexyl-
j urea. This derivative of the fatty acid is obtained by an 0 •* N migration of
I the primary addition product O-acyl dicyclohexylisourea. In order to
, achieve a complete conversion of fatty acids ( c1 2"
C20^ to t*ie^r corresponding
t-butyl esters without formation of N-acylurea, studies have been carried out
under various reactant , coupling agent and catalyst concentrations. As a
J result we can describe a simple one pot, high yield method for esterification
of fatty acids. 0
R-COOH + (CH 3) 3C0H DCC/DMAP R - C - O - C f C H ^ j (90-98%)
(1) E.F.V. Scriven, Chem. Rev. 1983, 129-161.
(2) A. Hassner and V. Alexanian, Tetrahedron Lett. 1978, 4475.
90
T019
PALLADIUM CATALYZED ALLYLIC ETHERIFICATION WITH TIN ALKOXIDES
Ehud Kciaan1, Mahmdra Sahai1, Zeev Roth1, Abraham Nudelman2, Jacob Herzig2
Department of Organic Chemistry, Weizaann Institute of Science, Rehovot, Israel2Depart*ent of Chemistry, lar-Ilan University, Ramat-Gan, Israel
Tin alkoxides, although mildly nucleophilic, were found to be highly reactive
nucleophiles towards *-allyl palladium intermediates. Thus, a chemoselective
approach to allylic etherification has been developed. Allylic acetates were
selectively substituted in the presence of primary halides:
Bu.SnOPhb w
OAc
This palladium catalyzed allylic etherification has been applied to carbohydrate
chemistry for selective glycosidation and protection of hydroxyl groups:
The similar reactivity of cyclic dialkoxides provided a short and useful entry
into macrocyclic unsaturated polyethers.
OAc
Pd(PPh-)d
94%
OAc
91
f TD20
HIGHLY CHEMOSELECTIVE REDUCTIONS WITH GROUP IVA METAL HYDRIDES ANDPALLADIUM CATALYST
Ehud Keinan tmd Noaa Greenshpoon
Department of Organic CheaistryThe Wei-w—i Institute of Science, Rehovot 76100, Israel
Metal hydrides of groups IVA eleaents together with a soluble palladium catalyst
allow very mild and eh—oselective reductions of allylic heterosubstituents and
Michael acceptors in the presence of other easily reducible functionalities,
such as benzylic heterosubstituents, ketones and aldehydes. A highly controlled
reduction of .in allylic acetate in the presence of a Michael acceptor or a
coapleaentary reduction of a Michael acceptor in the presence of allylic
acetate, can be achieved by an appopriate choice of the netal hydride:
OAc OAc
Ph
Ph
,CHO
The relative reactivity of twelve different silicone hydrides was determined by
kinetic studies using 270 MH: H NMR. Some Mechanistic aspects of these reduc-
tions, as well as synthetic applications in steroids and carbohydrates chemistry,
are discussed.
AcO Pd(pph3)4
2nCl2 Ph2SiH2
TD21
A NOVEL APPROACH TO TOTAL SYNTHESIS OF UBIQUINONES
Ehud Keinan and Doron ErenDepartment of Organic Chemistry
The Weizmann Institute of Science, Rehovot 76100, Israel
A general methodology for syntheses of various ubiquinones has been developed.
The key steps in the synthesis involve allylic coupling reactions based on
organo-copper and organo-palladium chemistry. Construction of the polyprenoid
side chains was achieved by a highly controlled palladium catalyzed olygoirieri-
zation of monomers derived from geraniol and other monoterpenes.MeO
MeO-
JOT 3 steps
2.3-dihidro- Vitamin Q?
n«i Vitamin Q<
n>2 Vitamin Q t
n«3 Vitamin Qj
n>< Vitamin Qw
>93 6
TD22
THE FMNftTION 4NO THE REACTIVITY OF
TOWARDS TCNE
3MEL, 1BMN MMtVISETSIRIKUL
Dept. of Pharmaceutical Chemistry, The Hebrew University School of Pharmacy,Jerusalem, Israel
Unlike the vinyl-cyclopropane system in (1) which cycleedds TCNE exclusivelyin the [24-2] cycloaddition fashion ( ! • £ ) , similar reaction of TCNE withdivtnyl-cyclopropane system in (2) leads to an adduct containing seven-membered ring (2 •»• £ ) . In view of these, we became interested to determinewhether the reaction of TCNE with the isoweric butadienyl-«p£n?-cyc1opropanesystem in (5) would lead to a di-apiiv adduct containing cyclopropane (6)and/or an angular tri-cyclic adduct containing a large ring (seven- or nine-aembered ring), (T) or (8).
I t wil l be shewn that both (6) and (J) could be formed depending on reactionconditions.
"5
TD23
FACILE FORMATION OF FIVE-MEMBERED RING SYSTEMS. aSYNTHESIS OF 1.3-DITHIANYLCYCLQPENTENES"
Q
NIPON WONGVISETSIRIKUL, SHALOM SARELDept. of Pharmaceutical Chemistry, The Hebrew University School ^ ^'.iriS' •'P.O. Box 12065, Jerusalem 91120," Israel
He have previously demonstrated °that Peterson's Reaction could be apol'-i.successfully for the synthesis of cyclorponyl-ketene dithioacetals, in hi^hyields.1 We wish now to report the abnormal behaviour o* cycle- 1 •)„. • r'v.--tones and of cyclorpopyl keto-esters towards 2-lithio-2-tv"inetli,yi:i ./I-1. -dithiane, leadino exclusively to rearranged orodi-cts v our.; a6 be•
rS
The reaction parameters of these reactions will be presenter! and discussed inconjunction with mechanistic considerations.
1 S. Sarel and N. Wongvisetsirikul, Abst. Papers presented at 3rd Eur. S:-ro.Org. Ch«n. (ESCO III), 5-9 Sept. 1983, Canterbury, i, OC-24.
95
TD24
SRDW-CYCLOPROPYL KE11NE DITHIOACETALS ASBUILDING BLOCKS TOWARDS FUNCTIONAL IZED CYCLOHEPTENES
SHALOM SAREL, NIPON WONGVISETSIRIKULDept. o f Pharmaceutical Chemistry, The Hebrew U n i v e r s i t y School o f Phamacy ,Jerusalem, I s r a e l
In continuation of our studies on reactivity through strain, we wish to de-monstrate the usefulness of cyclopropyl ketene dithioacetals as synthons to-wards functionaiized cycloheptenes. We report here the synthesis and thecycioadditions of the hitherto unknown tpiro-cyclopropyl ketene dithioacetals(3a - 3c) with TCNE to form the angular tri-cyclic systems containing seven-mmbered ring in high yields. The «ptw-cyclopropy1 building blocks were syn-thesized from the corresponding ketones following a Modified Peterson Reactionas portrayed below.
or en
Mt
- OM«; tt2 » H, iGj l £ , *£.
96
o TD25
FACILE FORMATION OF PtCNAOTHRENEQUINONE FROM BENZIL. A NEW SYNTHETIC USE OF
POTAtSHM-GMfMlTE INTERCALATE
Dov TAHMtXIN, DaphnaiENNY and Msrd«cai RABINOVITZ, Department of Organic
Cheaistry, The Hebrew University, Jerusalem 91904, Israel
Potassium graphite intercalate - CgK is a highly ordered reagent i.e.
potassium atoas are arranged in defined sites in the graphite lattice.
Therefore, it is expected to react with organic substances in a different -
•ore specific «ode relative to potassium metal. Previously we could show that
CgK can be used for binolecular reductions of e.g. ketones to pinacols.
In a search for further applications of this reagent, it was found that
benzil is converted by CgK to phenanthrenequinone and that other a-diketones
afforded quinones. During the reaction hydrogen gas evolution was observed
and followed kinetically. _ ,,i 8
Table: Products of the reaction: Ar(CO)(CO)Ar- *• phenanthrenequinone + H_
benzil products
o o :
>• \
v *- ^ *•• r^
Phenanthrenequinones, which are difficult to prepare by alternative methods
can be obtained by this mild reaction in good yields, and high purity. The
aechanim of this reaction will be discussed.
97
TD26
THE APPLICATION OF PTC/OD" FOR DEUTERIUM EXCHANGE IN WEAK CARBON ACIDS
David FELPMAN, Marc HALPERN and Nordecai RABINOVITZ
of Organic Cheaistry, The Hebrew University, Jerusalc 91904, Israel
Eaployaent of aqueous sodiun hydroxide under phase transfer catalysis
conditions (PTC/OH" systems) has been accepted as the method of choice in
•any ba**-catalys«d organic reactions. Deut©ration of organic acids has been
pwfen—a in the presence of quaternary aawonium salts. So far deuteration
has been limited to compounds as, or more, acidic than thiazole. We have
shewn that the hydroxide ion nay be extracted into the organic phase under
PTC/OH" ceftuitions and that an increased basicity of the hydroxide ion is
expected, relative to that of the hydroxide ion acting at the interface. This
.difference is due to their relative state of hydration. This enhanced
basicity has been applied to extend the scope of PTC/OH" base catalysed
reactions. Deuteration of very weak carbon'acids even as weak as ortho-
halotoluenes and related compounds have been performed under extractive
PTC/OD' conditions.
98
0 TD27
CATALYTICALLY ACTIVE RUTHENIUM SPECIES IN THE OXIDATION OF ALCOHOLS TO ESTERS
Y. SHVO t n d Y . BLUM
Department of Chemistry, Tel-Aviv University. Tel-Aviv 69978, Israel
Ru3(C0)j2» i n t h e P r e s € n c e ° f a H-acceptor, was found to function as a catalyst
precursor in the oxidation of alcohols to esters:o
Ru,(C0)192RCH-0H J — * • RCO-CH,R + 4[H]
o
The reaction is general for a wide variety of primary alcohols and character-ized by high conversion and selectivity. Diols (a,u) yield lactones.The above catalytic conversion proceeds in two steps:
RCHO + RCH20H »- RCOgCHgR + 2[H]
A complex equilibrium system involving the organic substrates as well as organ-ometallic intermediates prevails during the oxidation reaction. The aldehydepersists in a steady state concentration and a degenerate alcohol aldehydeinterconversion takes place.
When diphenylacetylene is used as H-acceptor, FU^C-Cj^prhCg^ as we^ as
another crystalline Ru complex were isolated; both are catalytically active inthe above oxidation reaction. Seven known "u clusters bearing both PhpC- andCO have been independently prepared and found to exhibit a variable degree ofcatalytic activity. Our experimental results point toward a catalyticallyactive species becoming irreversibly bound;diphenylacetylene molecules.A catalytic cycle for the oxidation of alcohol to esters with Ru3(C0)12 « acatalyst precursor will be proposed.
99
TE1
CYCLIC REDUCTION OF KETO-SUBSTRATES BY NAD(P)H MODELS
P. DAN, N. VITNOF and I. WILLNER
Department of Organic Chemistry, Hebrew University of Jerusalem, Jerusalem,
Israel
The nicotineamides (1) and (2) were used as NAD(P) models. A two phase system
composed of 4,4'-bipyridinium, (3), the NAD(P)+ model (11 OT (2J . Zn++-ions
and a reductant such as .'.n-inetal, leads to the reduction of ethyl benzoyl-
formate (4) to ethyl mandelate (5), (eq. 1). The components (1_1, (.1) and (3)
are present in catalytic amounts and are recycled during the conversion of
(4) to (5>). Similarly, Zn -ion are essential t? accomplish this reaction.
0
t 1 !
o oCNIl-CH-.'i-OK
(2)
01!
$-CH-CO,Et*-C-CO.,Et 1
(£) (5) l^ (1.)
The detailed pathway leading to the reduction of (4_) has been verified. The
bipyridinium salt, (5) is reduced to the corresponding radical catioa that
subsequently reduces the NAD(PJ models to the respective 1,4-Jihvdronico-'.i-e-
amides (NADPH models) (eq. 2). The NAL!;T)il models form a 1:1 complex '•• th
Zn -ions. This complex activates the keto substrate towards the
process, (eq. 3 ) .
2(3)"* + ' NADPH /'•'(2) 2(3_)- + NAD(P) • H -
(3) NADPH + Z n + t e ~ = * J[Zn+4"-MD(P}H]
Photochemical transformations involving NAD(P)H models as well as KAD(Pjli)' .y ,
dependent enzymes have been accomplished also. <,
100
< .n
•
WALLACH REARRANGEMENT STUDIES IN THE PNENYifAZOXYPYRIDINE SERIES. STRUCTURf
ANO REACTIVITY STUDIES OF ISOMERIC o AND 6 PHENYLAZOXYPYRIDINES, N-OXIDES
AND HETHIODIDESE. BUNCEL*, S.R. KEUM*. H. CY6LER+, K. I . VARUGHESE , AND G. I . BIRNBAUM?,|Department of Chemistry, Queen's University, Kingston, Canada K7L 3N6^Department of Biochemistry, University of Alberta, Edmonton, Canada T6G ZH7^Division of Biological Sciences, National Research Council of Canada,
Ottawa, Canada K1A 0R6
1 2In an extension of Wallach rearrangement studies • into the
phenylazoxypyridine series, an investigation of 4 - , 3- and 2-phenylazoxypyri-
dines, uie N-oxides and methiodides is reported. Oxidation ot 4- and 3-
phenylazopyridine with peracetic acid gives rise to the a and £ phenylazoxy-
pyridine-N-oxides, contrary to previous l i terature reports on the obtention
of the a isomers solely. 2-Phenylazopyridine, however, yielrjs only the
2-(phenyl-a-azoxy)-pyridine-N-oxide. These results are rationalized on the
basis of f i e l d , resonance and steric effects. An unprecedented reactivity
difference has been observed in the reactions of the a,8 isomers of phenyl-
azoxypyridines under conditions of the Wallach rearrangement. This reactivity
difference permits the isolation of the a azoxy isomers from the a,6 mixtures,
and provides clues concerning the rearrangement mechanism.
Unequivocal confirmation of the structures has been obtained from
X-ray crystal structure determinations of two representative compounds in
this series, v iz . 4-(phenyl-6-azoxy)pyridine-N-oxide (1_) and 4-(phenyl-a-azoxy)
pyridinium methiodide (2) which i tse l f was formed by deoxygenation of
4-(phenyl-a-azoxy)pyridine-N-oxide, followed by methvlation with methyl iodide.
Structural differences between J_ and 2_ bear analogy to the differing reac-
t i v i t i es of a and e phenylazoxypyridines in the Wallach rearrangement, being
related to charge delocalizabil ity in the ground state and in the transition
state, respectively.
1. E. Buncel, Ace. Chem. Res. 1975, 8, 132.
2. E. Buncel and S.R. Keum, J. Chem. Soc. Chem. Commun. 1983, 578.
101
TE3
THE AUTOMERIZATION MECHANISM ANO STRUCTUREOF THE C n H 1 1 ARMILENYL CATION
M.J. Goldstein, J.P. DinnocenzoDept. of Chemistry, Cornell University, Ithaca, NY 14853, U.S.A.
The facile nucletr permutations of the "armilenyl" cation (i)—(1,2,3,8,7)(4,6,9,11)(5,10)--have hitherto obscured both its static structure and themeehMisM of its automerizition.1 1JC NMR spectraat -164°C have now solvedth« structural problem. Resolution of the originally reported 3 lines into 8excludes the C2 version of ib. The dispersion of chemica^l shifts, e.g.,<%.ii"214.66, 6i.«71.61, excludes the C, version of tb and requires ia .
1b
Subsequent line-shape analysis (-160°* -80°C) Solves, the Mechanistic problem.If m were instead an internally rotating transient intermediate, it shouldrequire the Cl,8 and C2.3 NMR signals of 1« to broaden at an equal rate.A more conventionally achieved transient (2) should require the first of theseto broaden half as rapidly as tha second. The first signal actually broadenstwice as rapidly as the second. The simplest consistent mechanism is theoriginally proposed, but rare, allylic alkylation of a cyclopropane^carbonwith inversion of configuration: ",
(1) Goldstein, M.J.; Tomoda, S.; Pressman, E.J.; Oodd, J.A. J.1 ••1,103, 6530 and references cited. (}
102
. Soc.,
• \v
TF1
THE EFFECT OF PARTIAL PRESSURES ON MASS TRANSPORT OF CdTe BY VUVG, ,0
H. YELLIN*. L. BEN-DOR***Dept. Solid State Physics, Soreq Nuclear Research Center, Yayne, Israel
**Oept. Chemistry, Hebrew University, Jerusalem, Israel i L/
High quality, large,single crystals of CdTe with characteristics well suited
for optoelectronic devices and nuclear detectors were grown by the vertical
unseeded vapor growth (VUVG) technique (1). .Charges \*ere either stoichio-
metric or Te rich, with the excess Te (6Te) in the range 0-0.1 mol*. Mass
transport was found to be strictly dependent on <5Te, the behavior being dif-
ferent for 0 < <5Te $ 0.02 mol% and for 0 • 6Te * 0.02 m\%. Partial pressures
of Te and Cd were calculated for these 6Te ranges at the growth temperature,
933°C. The calculated pressure values explain the experimentally found mass
transport behavior. , - ,y
(1) N. Yellin, D. Eger and A. Shachna; J. clyst. Growth, 60, 343 (1982).
•f"
S03
TF2
LOW TEMPERATURE SYNTHESIS OF PSEUOOBINARY CHALC06ENIDES
L. BEN-DOR*, N.° YELLIN***Dept. of Chemistry, Hebrew University, Jerusalem
**Dept. of Solid State Physics, Soreq Nuclear Research Centre, Yavne
Alloys of II-VI and IV-VI semiconductors are used in electrical and opto-
electronic devices. For these applications, high purity single crystals are
required. Usually, the synthesis of the material is part of the crystal growth
process and is carried out at temperatures above the liquidus of the system.
Solid solutions of eight pseudobinary metal chalcogenides: (PbSn)Te, (PbSn)Se,
(HgCd)Te, (HgZn)Te, (CdZn)Te, Cd(TeSe) and Pb(TeSe) were prepared at low
temperatures from their elements. Complete reaction was oDserved at tempera-
tures significantly lower than their melting points, in 3-7 days. Homogenization
required annealing at higher temperatures, for up to 14 days, but still at
temperatures below the melting points. The compositions of the alloys were
determined by XRD. Working at low temperatures, reduces charge contamination
by impurity diffusion from the auartz ampoule, thus providing an improved
technique for obtaining semiconductor materials.
104
TF5o
ESR AND MAGNETIC SUSCEPTIBILITY STUOIES OF GRAPHITE INTERCALATED WITH TRANSITIONTRANSITION METAL HEXAFLUORIDES
\ !)- H. SELIG», D. VAKNIN1. D. DAVIDOV \ Y. YESHURUN 2
f 1. Racah Institute of Physics, Hebrew University. Jerusalem, Israel .2. Dept. of Physics. Bar-Han University, Ramat Gan, Israel . ,,3. Institute of Chemistry, Hebrew University, Jerusalem, Israel .
•0
Esr signals attributed to intercalated paramagnetic species in Highly OrientedPyrolytic Graphite (HOPG) with metal hexafluorideV MF6 (M = Mo, K Os) forStage I compounds were observed for the first time. A single metallic esr line
s exhibiting significant field anjsotopy was observed. The field dependentf could be fitted to g2 * gS cos 2e + g* sin ze 'with gpl = 1.73 ± 0.0? r-.j
g^ = 3.23 for H0PG/0sF6 at T * 6K. These g-values are temperature incependentabove 6K. Signal intensities diminish with increasing temperature roughlyaccording to the Curie law. No resonance associated with conduction electronscould be observed.
LI
Susceptibility data and the temperature dependence of the esr lineintensity strongly support crystal field effects as the main mechanism 'accounting for the g-values. For H0PG/0sF6 they are consistent with inter-calated 0sF^(5d3). For this configuration, perturbation theory by Griffithyields g, ~ 2g',,, in rough agreement with experiment. The ratio of spin-orbitcoupling to overall crystal field splitting, c/A, -is estimated to be 0.1. The ~results show well-defined symmetry and uniform orientation within the graphiteplanes leading to characteristic crystal field effects. In contrast toBartlett's results, we find no evidence for magnetic phase transitions at ~20Kin CnIrF6 and CpusF6. ^ ^
J1J
105
TF4
DOPING OF POLYACETYLENE FILMS TO THE METALLIC STATE WITH TRANSITION METAL
PENTAFLUORIDES AND HEXAFLUORIDES
H. SELIG*. J.H. HOLLOHAY**
*Dept. of Inorganic 4 Analytical Chemistry, Hebrew University, Jerusalem, Israel**Chemistry Dept., The University, Leicester, U.K. LE1 7RH
Many acceptors have been shown to dope poiyacetylene (CH)X to the metallic
state. The conductivity of the (CH)X films may change as much as twelve orders
of magnitude in this process. We have found two new classes of acceptor com-
pounds which dope polyacetylene to the metallic state: the metal hexafluorides
and pentafluorides. This should make it possible to study systematically the
effect of electron configuration and associated properties on those of the re-
sulting doped polymers. The electrical conductivities and weight uptakes of
(CH)X films exposed to MF6 (M = Se, Te, Mo, W, Re, Os, Ir, U) and to HFS (M =
Nb, Ta, Mo, W, Ru, Bi) vapors were Pleasured. The maximum conductivities reached
with MFs vapors indicate an inverse correlation with their election affini-
ties. The most likely reaction is
(CH)X * nMFfi - [CH+(MF;)n]x
Similarly, the maximum conductivities attained with MF5 vapors show an inverse
correlation with their fluoride ion affinities. These inverse correlations may
be due to increased charge localization leading to lower mobilities of the
charge carriers, as has been postulated for the analogous graphite intercala-
tion compounds, or martial fluorination, with consequent decreased mobilitie:.
Curves of conductivities vs. degree of doping obtained for WF,, NoF, and UFCare qualitatively similar to those obtained with AsF, and 1 ., showinc; a
semiconductor to metal transition at about 2-5% doping. Esr spectra at these
concentrations show line shapes characteristic of metallic behavior.
106
TF5
THE NEW DINUCLEAR TIN-HAUDE ANION - Sn2Ci2 -10
J. SHAMIR, S. LUSKI, A. BINO, D. GIBSON, S. COHENDept. of Inorganic * Analytical Chemistry, The Hebrew University, Jerusalem,Israel.The newly discovered dimeric anion - Sn2C*~ in a solid, 1s obtained byreacting PCJU and SnC4v via chloride anion transfer, according to:
This reaction takes place in non-aqueous solutions, such as CH2CZ2 or POC&,.The structure of the compound was verified by single crystal X-rays analysisand its vibrational spectra was determined both by laser Raman and far Infraredtechniques. The ion consists of two edge-bridged octahedrons.
107
TF6
EPITAXIAL GROWTH OF CALCIUM OXALATE ON URIC ACID
S. SARIG, D. HIRSCH and N. GARTIThe Casali Institute of Applied Chemistry* The Hebrew University of JerusalemJerusalem, Israel -
Part of calcium oxalate !<idney stones are formed around a nidus of uric acid.This study was undertaken to determine whether epitaxial growth of calciumoxalate occurs on crystals of uric acid or sodium urate. An experimentalsystem of calcium oxalate metastable solutions was defined and monitored byspecific calcium electrode. The metastable condition was ascertained byconstancy of the electrode measurement during the specified period and lackof visible turbidity. Seed crystals of either uric acid or sodium uratewere introduced into the solution and the decrease of calcium ion concentra-tion was noted. The seed crystals were separated and inspected by SFtt. The
0
presence of calcium on the surface of the seed crystal was measurso' by analy-sis of induced x-ray radiation (LINK). It has been found that calcium oxalateis deposited on sodium urate in a time interval compatible with the urineresidence in the kidney, but no deposition on uric acid seeds was observed.These results which are in excellent agreement with the conclusions of studiesin the0 literature form are in conflict with the clinical fact, that uricacid is found in niddi of calcium oxalate stones. In light of this irrelationthe above described experiments with uric acid were modified by addition of4-5 ppm glutamic acid. Significant decrease 1n calcium concentration occurredand calcium was found on the surface on uric acid crystals. These findingsmay contribute to management of kidney stone disease, especially forhyperuricosuric patients.
106
TF7
A THENMOGRAVIMETRIC STUDY Of MAGNESIUM AND STRONTIUM
CONTAINING CARBONATE HYDROXYAPATITES
I. MAYER*. D. DEUTSCH**, R. NAGLER**, I. GEDALIA**, J.D.B. FEATHERSTONE***of Inorganic ft Analytical Chemistry, Hebrew University.Jerusalem,Israel
Carbonated hydroxyapatites (CA) containing Mg and Sr were synthesized and
their composition, crystal properties and solubility investigated. The present
study reports the thermal analyses of these compounds by thermogravimetry (TG).
Hydroxyapatite samples with a carbonate content up to 8.0%, Mg up to 0.6%
and Sr up to 0.15% were studied. The TG analyses were performed in the
temperature range of 25°-950°C, at a heating rate of 10°C/min under nitrogen
gas flow. Following TG, the samples were analysed by IR and by X-ray
diffraction (XRD). The TG diagrams obtained indicate a gradual decomposition
of the carbonate in the samples between 350°-950°C. The weight loss related to
complete decomposition of carbonate agreed well with carbonate determined by2 +
IR; in case of Mg weight loss was significantly higher than carbonate found
by IR. XRD patterns of the decomposed samples showed in addition to the
apatite phase the presence of whitlockite, (Ca, Mg)3(P0O2, in all the Mg
containing samples. The lattice constant a of the decomposed CA was in
most"cases higher than in the apatites before heat treatment. The higher
weight loss associated with Mg containing CA might be due to carbonate out-
side the apatite phase or another decomposing ion. Increase in Mg++ content
causes an increase in the amount of the decomposition products.
109
TF8
THE EFFECT OF THE CHANGE FROM SQUARE PLANAR TO OCTAHEDRAL COORDINATION ON THE
pICa OF THE LIGAND IN CONJUGATED UNSATORATED TETRAAZA-MACROCYCLIC NICKEL COWLEXES
H. COHEN, N. NUTKOVICH, D. MEYERSTEIN, A. SHUSTERMAN
Chemistry Department, Ben-Gurion University o f the Negev ;
and Nuclear Research Centre Negev, Beer-Sheva, I srae l
The pKa'5 f o r the l igand in the d i - and terva lent nickel complexes with
11,13 d imethvl -1 ,4 ,7 ,10- te tramzacyc lotr ideca-10 ,13 diene, L ^ and l l -methy l -13-
t r i f l u o r o m e t h y l - l ^ . T j l O - t e t r a a z a c y c l o t r i d e c a - l O . l S diene, L_, were measured. '
The r e s u l t s are 6.55 and 8.8 for NiL*+ and NiL.(H_O)'+ and 0.84 and 5.12+ 3+
for NiL- and NiL-(H-O)- r e s p e c t i v e l y . These r e s u l t s are surpris ing as
one expects that due to the larger induct ive e f f e c t the l igands of the terva lent
nicke l complexes should be more a c i d i c . A p laus ib le explanation of th i s
unexpected r e s u l t i s that the HOMO of the TT system of the deprotonated l igand
is differently stabilized by the interaction with the nickel 4p orbital inthe di- and ter- valent complexes. In the planar divalent complexes the 4porbital i s non-bonding whereascit is antibonding in the octahedral tervalentcomplexes. Thus i t is plausible that the 4p orbital is higher in energy inthe tervalent complexes i f the change from non-bonding to antibonding more -than compensate the change in charge. In this case the * system formed due todeprotonation will be more stabilized in the divalent complexes thus explain-ing the experimental observations. The spectra and kinetics of dimerirationof the tervalent complexes are reported.Acknowledgement. This study was supported in part by the U.S.-Israe
Binational Science Foundation, B.S.F., Jerusalem, Israel.
110
TF9
KINETICS AND MECHANISM OF THE g-HYDROXYL ELIMINATION
FROM [(H,O)_Cr-CHR 1CR,R_OH] 2 + IN AQUEOUS SOLUTIONS2 5 1 2 3 ^
H. COHEN, D. MEYERSTEIN, A.J. SHUSTERMAN, M. WEISS
Chemistry Departments, Ben Gurion University of the Negeyand Nuclear Research Centre Negey, Beer-Sheva, Israel
The alkyl chromium complexes [(H2O)5Cr-R]2+, where R * CH^OH, C H C C ^ ^
CH(CH_)CH(OH)CH, and CH,C(CH,),OH decompose to y ie ld Cr(H,O)f+ and the
corresponding alkene. For the la t t er two alkyl residues the reaction proceeds
via a re la t ive ly stable intermediate. This intermediate i s ident i f ied as
20>SCH
3+
\ formed by an acid catalysed £ elimination reaction. The
identification of the intermediate as the electron-deficient d ->• IT* complex
and not as [(H-OJ^Cr-CR.-CR_R_]2+ or [(H,OJ Cr-CHR.-CR *CH ] 2 + as earl ier
suggested i s based on the observation that the 2 methyl propene formed in D70,
for R = CH C(CH ) OH, contains no deuterium above the natural abundance level .
(Measurements for R = CH(CH3)CH(O!1)CH_ are in progress). For R = CH?CH,OH
and CH CH(OH)CH, the same mechanism is proposed and the lack of observation of
an intermediate i s attributed to the fact that the B elimination reaction
becomes the rate determining step in the reaction sequence. The factors affect-
ing the rate of the 8 elimination reaction and the relative s tabi l i ty of the
chromium(III)-alkene d -»• IT* complex are discussed.
Acknowledgement. This study was supported in part by the U.S.-IsraelBinational Science Foundation, B.S.Fl/, Jerusalem, Israel.
Ill
TF10
OXIDATION" OF TERVALENT URANIUM, U , BY FREE RADICALS IN AQUEOUS SOLUTIONSaq
H. COHEN, D. GOLUB AND D. MEYERSTEIN
Chemistry Departments, Ben Gurion University of the Negev, Beer-Sheva, Is rae l
Tervalent Uranium i s a strong reducing reagent, e^(U +/U +) «= -0.63 V vs.
N.H.E., and has been used extensively as an outer sphere electron reducing
reagent in aqueous solut ions . The specific ra tes of oxidation of U in 0.5 M
HC£O4 by OH, Ce~, Br~, I~, (SCN)", •CH,CO2H and -CH(CH3JCO,H are 4.1 x 108 ,
4.2 x 109 , 3.4 x 109 , 1.2 x 109 , 1.4 x 109 , 1.2 x 108 and 2.1 x io ' M^s" 1
respect ively. The oxidations by the X, radicals proceed via a short lived
intermediate thus indicat ing a bridged mechanism. The same mechanism probably
describes the oxidation by the »CH(R)C07H radicals which are poor outer sphere
oxidants. Two mechanism? have been suggested for the oxidation of aquo complexes
by hydroxyl r ad ica l s . 1. The bridged mechanism. 2. Hydrogen abstraction from
one of the aquo l igands. The present resu l t s seem to indicate that the U *
i s oxidized via the bridged mechanism, i . e . the OH penetrates the inner
coordination sphere of the central" cat ion.
Acknowledgement. This study was supported in part by the U.S.-Israel
Binational Science Foundation, J5.S.F., Jerusalem, I s r a e l .
112
TF11
CHROMIUM PORMYL COMPLEXES IN AQUEOUS SOLUTIONS
H. COHEN, D. MEYERSTEIN, A. SHUSTERMAN AND M. WEISS
Chemistry Departments, Ben-Gurion Univers i ty o f the Negevand Nuclear Research Centre Negev, Beer-Sheva, I s r a e l
The radica l »CH(OH)2 (which i s produced by the reac t ion o f hydroxyl r a d i c a l s ,
OH, with hydrated formaldehyde) reac t s with chroaous ions i n aqueous s o l u t i o n s
to fora a coaplex with a chromium carbon bond. The s p e c i f i c ra te o f formation
o f (H_O)_CrCH(OH)^+ i s 1.0 x 108 M ' V 1 i n a c i d i c s o l u t i o n s . The l a t t e r- 1 - 1coaplex i n a c i d i c s o l u t i o n s has a spectrum with A * 305 nm (e«23OO M cm )
-1 -1 B a x
and a shoulder at 375 nm (e«410 M cm ) . In a c i d i c s o l u t i o n s pH 1 . 0 , and
0.1 M CH,(OH),, (H,O) Cr-CH(OH)-?* o r (H,O).Cr-CHO2+ whichever i s the i n t e r -
mediate observed, decoaposes in a pseudo f i r s t order process with k * 0.034 s
At pH 6 .0 the formation o f (H 0) Cr-CH(OH) _+ i s fol lowed by two consecut ive2 - 1reac t ions obeying pseudo f i r s t order ra te laws, with k « 1.5 x 10 s and
k * 0.35 s respectively. The f i r s t reaction i s probably the dehydration
reaction (H^gCr-CHCOH)2,* ->• (H2O)5Cr-CHO2++H2O as the spectrum of the second
intermediate indicates that the chromiurn-carbon bond i s kept intact . In the
second reaction the chromium carbon bond decoaposes yielding chromium(III)
Carbon monoxide i s a final product at both pH's though no dihydrogen i s
observed. The mechanism of decomposition i s discussed.
Acknowledgement. This study was supported in part by the U.S.-Israel
Binational Science Foundation; B.S.F., Jerusalem, Israel.
113
TF12
THE MECHANISM OF HYDROLYSIS OF THE ALKYL-CHRDMHJM(III) BOND
IN AQUEOUS SOLUTIONS
i'/A. KXIHMW , H. COHEN, D. MEYERSTEIN
ChMdstry Departments, Ben-Gurion University of the Negevamd Nuclear Research Centre Negev, Beer-Sheva, Israel
Recently i t was reported1 that the kinetics of hydrolysis of the metal-carbon
toad in the complexes (edta) Cr(III)-CR1R2OH"2, where R ^ - H or Ctiy
d[(edta)Cr(III)-CR R OH"2Jobey the rate law - ^ « [kH Q+kH Q +] *
fTTT-i Jy 2 3
[(edta)Crv -CR,R2OH ] . The fact that the specific rate constants kH Q are
identical to those reported for the analogous hydrolysis reaction of the
(H2O)sCr(III)-CR,R2OH complexes, though the free energy gain in the former
reactions is'Olarger, was interpreted as suggesting that the hydrolysis reaction
of (H 0} Cr(III)-CR R OH involves the participation of the cis H70 ligand.2
We have neasured the kinetics of hydrolysis of [N(CH2CO2)3]Cr(III)(H20)-C(CH3)2OH~
and found that the rate of reaction i s pH independent between pH 4.0 and 7.0
and that 1^ Q i s identical to that reported for (H2O)5Cr(III)-C(CH3)2OH2+
and (edta)Cr*(III)-C(CHJ OH"2. This result clearly indicates that the cis HO
lifand has no aajor role in the hydrolysis process. Furthermore, as trans
acetate ligands enhance the rate of hydrolysis3 i t i s suggested that the
-CRjR2OH ligand i s trans to a tertiary nitrogen in (edta)Cr(III)-CR,R2OH2"
and [N(CH2CO2)3]Cr(III)(H2O)-CR1R,OH".
Acknowledgement. This work was supported by the U.S.-Israel Binational ScienceFoundation (B.S.F.) , Jerusalem, Israel.
1. Ogino, H.; Shimura, H.;. Tanaka, N., Inorg. Chem. 19S2, 2l_, 126.
2. Espenson, J.H., Advances in Inorganic and Bioinorganic Mechanisms,
Vol. 1, Academic Press (London) 1982, 1.
3. Cohen, H.; Meyerstein, D., in press, Inorg. Chem.
114
TF13
A NEW FEATURE OF HYDROLYSIS OF METAL IONS IN SOLUTION:
DIMERIZATION OF HYDROXOAQUA IONS
M. ARDON*, B. MAGYAR**
* Dept. of Inorganic & Analytical Chemistry, Hebrew University, Jerusalem, Israel** Laboratories fur anorganische Chemie, ETH, Zurich
The bridging of metal ions by means of hydrogen oxide bridges (H302) was first
reported by Bino and Gibson1 in crystals of salts of trinuclear cluster ions
of molybdenum and tungsten. The H302 bridge is formed by a short symmetrical
hydroaen Dond between an H80 liqand of one metal atom and a hydroxo ligand of
another. Recently2 this bridge was shown to exist in crystals of classical
"hydroxoaqua" ions, such as the so-called cis-bis bipyridil hydroxoaquachromium
(III) ion which is in fact a doubly bridged dimer [(bpy)2Cr(H30s)2Cr(bpy)£3't+.
This bridging by HjO2 is quite general and exists in crystals of all the
"hydroxoaqua" ions investigated^ far3 (including both "cis" and "trans"
configurations). Our present picture of hydrolysis of metal ions in solution
may have to be radically altered if aqua ions such as Cr(HaC)50H24 exist as
dimers in aqueous solution. Preliminary evidence obtained by Three Phase VaDor
Tensiometry (TPVT) measurements of [Cr(bpy)2(H20)(0H)3£+ in a saturated f.a(?;0..):
solution, confirm that at relatively high concentration (0.2M) most of the
chromium ions are dimers.
: a) Bino, A.; Gibson, D. J. A\. Che*;. Soe. 1981, :. •", 6714;
b) i b i d "982, ?•:•?, 1383;
c) idem. Inorg. Chem. ( in p r e s s ) .2 Ardon, M.; Bino, A. J. Am. Cham. Soc;( in press).3 Ardon, M.; Bino, A. ( to be published).
TF14
STEREOCHEMISTRY AND STRUCTURE OF COMPLEXES OF DIMOLYBDENUM (I I ) WITH DL-AMINO
ACIDS
F. APFELBADW-TIBIKA, A. BINO
Dept. of Inorganic and Analytical Chemistry, Hebrew University Jerusalea , I srae l
4+The reaction of (KW=M«) with the racemic mixture of amino acid DL-A, mayyield the following isoaers: MO2Dif,Mo2D3L,Mo2DDLL, Mo2DLDL,Mo2DL3 and Mo2U.
Provided that no steric interactions exist between the chiral centers in the
complex Mo2Allit can be shown that the s ta t i s t i ca l distribution of thege isomers
in solution should be in the ratios 1:4:4:2:4:1 respectively. The reaction of*k>2 +with DL-Phe, Dl*-tyr and DL-C-phej>ly, followed by the addition of various
counter ions yielded exclusively one crystalline product, namely, M02DDLL.
The structure of the three crystals was determined by X-ray analysis. The
diweric (Mo2DDLL) cations in the three structures reside on a crystallographic
inversion center and the four chiral ligands are arranged around the Mo-Mo
unit in the cyclic order of DDLL.
116
TF15
AN ac IMPEDANCE AND OPTICAL STUDY OF OXIDE FILMS
J . RISHPON, S. GOTTESFELDDepartment of Chemistry, Tel-Ayiv University, »amat Aviv, Israel
Combined eiiipsometric and ac impedance measurements were employed for in-situ
investigation of anodic oxide films on Ru and I r , and of oxide films formed by
thermal decomposition of Ru chloride. These oxides exhibit electro-catalyticy
act iv i ty in the oxygen evolution reaction, which is correlated to the oxide
structure, i ts water content, and i ts ionic and electronic conductivities.
The ellipsometric measurements provided information on oxide thickness,
porosity and water content. Film growth on the metal was controlled and monitor-
ed by the computerized automated system developed by us, and charging processes
occurring in the f i lm as a result of changes in the applied bias were followed.
I t was found that cathodic polarization of Ru oxide films causes an increase in
the water content of the f i lm. The ac impedance measurement performed auto-
matically in a large frequency range provided information about the kinetics of
the double injection processes of protons and electrons into the oxide layer as
a function of oxide thickness and structure, electrolyte composition, and
applied bias. The ac impedance results were analyzed in terms of equivalent
circui ts . The charging process in Ru oxide was found to depend mainly on proton
mobility within the f i lm. I t could be resolved into a faster mode, attributed
to charging of grain surfaces, and a slow bias dependent mode which involves
incorporation of aqueous protons into oxide grains. The effective diffusion11 l? "
c o e f f i c i e n t o f t h e p r o t o n c a l c u l a t e d f o r t h e s l o w p r o c e s s i s 1 0 - 1 0 c m 4 /s e c .
117
w
TF16
IMMOBILIZED CROMi ETHERS ANION EXCHANGERS - ELIMINATION OF WATER SPLITTING IN
ELECTRODIALTSIS.
A. Warshavsky*, I. Hobinstein** and O. Kedea***
Departments of Organic Chemistry*, Appliad Mathematics**, and
Membrane Research***, Weiamann Institute of Science, Rehovot, Israel.
Water splitting, namely the transport of H+ and OH" through cation and anion
exchange membranes, respectively, la an undesired phenomenon accompanying
elactrodialysis.1 R. Simons suggested that water dissociation is caused by
reversible protonation of the basic NK3 groups present in the anion exchange
•ambrane (AM).
From a general chemical point of view, alkali metal cations, if immobilized by
the attachment to uncharged crownether polymers, are excellent candidates for
the required positive charges of an AM. In this communication, we describe the
preparation of such membranes, and the way in which transport and polarization
tests were carried out in a four compartment cell. The results indicate
absence of water splitting at the surface of the new immobilized crownether
membranes.
1. R.A. Cook, Electrochim Acta, 2» 307 (1961).
2. R. Simons, Nature, 280, 824 (1979)» Resalination, 28, 41 (1979).
118
TF1"
STRUCTURE OF NATION AND ITS TRANSPORT PROPERTIES
C. HEITNER-WIRGUINOept. of Inorganic & Analytical Chemistry, The Hebrew University, Jerusalem,Israel.The composition and structure of ionic clusters in a series of cation exchangemembranes has been investigated by infrared spectrum, Mossbauer effect andtransmission electron microscopy. From these measurements the clusters weredefined as a function of membrane type, capacity and solvent. The diffusionof a series of cations in two membranes has also been studied and ionic fluxesand apparent diffusion constants evaluated. The water uptake of the membranein the various cationic forms explains the trends in the rate of diffusionwhich differ from those in the conventional crosslinked ion exchangers. Theresults obtained here may be interpreted in terms of a model consisting of ionclusters in the polymeric matrix. The rate of transport is related to therelative amount of ions in the clusters, as well as to the mean diameter sizeof the clusters formed.
119
TP1S
Lip?philic Dioenzo-'k-(i -ow:.-4 Co:.r,ounds AS ionopnorss For Alkali
And Aj.k-J.ine Earth Metal Cations In Soiv. nt-Poiy.'.e-ic M
U. Olsh.r*,G. Shohazi**,*.!!. Lipscomb** G. S. Heo***,R.A.
* D. .-.rtment of Biological Chemistry,'Harvard Medical School,
Boston, MA 02] 15. USA
« *Department of Chemistry, Harvard University, Cambridge, MA
02138 DSA.
Department of Ch siistry, Te;cas Tech University, Lubbock, Texas
A "series of electricaxiy neutral ,-uid r.ar-~—CP.I
14-cn n-4 cj...oou ••• 1.1) , in ivnj.ci.' H=-h, -OH,.--OuHpCI
- OCHCO H were prepared in order to investigate. .;. . .r
for axkaxi .iiid alkaline earth mrftiu cations in s-.-dvant-poly::.eric-
membranes ^pi-st is i^e * PtfC membranes/. Gonsiaer.-i.tie s^l activity
changes v;ere cosarved vihen ihese ionophores .'ere incorporated in t :
the s:.lvent-prlyr:;eric membranes.
The jneffibran* select ivi ty i s a function of thp molecu-.ar structure
and number of ionophore biniine,- s i t e s . Dibenzo-i4-Crown-4 (4
binding s i t e s ; ly etheral orcygens) membrane i s most selective t;
Li+; sym-hydrnxydibenao-iif-crovm -1+ (5 bindii:&- sites;i+ etherai
Oxygens .xd 1 hydroxyl group) nembrane i s most selective to K+j
sym-dibsnzo-1/+-cro\m-4-oxyethyl metyl ether (6 binding s i t . s j 6
ether^l oxygens) !i;en;bran= i s r/jost selective to Rb+; "and
sym-dibpn?.o-Hi-Gro-7n-.!!-?r:ys'c-=t:".c acid, (7 bindi'if -i'"-r,* ;• ?"h-?r--.l
oxygens &n I 'd c-arboxylcvt;- o;;y5ens) membrane i s rr.cst s-lec:iv-^ ;c
K+. The count.r-i^n effsct has o~an studied.
120
TF19
AN ELECTROMETRIC METHOD FOR THE STUDY OF LlOUin ION EXCHANGERS
Gideon Harei and Gabriella Schmuckler; Department of Chemistry,Technion, Israel Institute of Technoloqy, Haifa, Israel.
An electrochemical cell was designed and constructed for the measurement of thebarrier membrane potential, the lianid between the two membranes that constitu-ted the barrier beino a mixture of a liquid cation and a liquid anion exchanger.
The barrier membrane is interposed between two anueous salt solutions of knownconcentrations, one of which serves as the reference, the other is the samplecontaining 1 and j ions. The membrane potential, E, is measured notentiometri-caily with the aid of two identical Ao/AoCWKCl sat. reference electrodes, onein each of the salt solutions.
The DOtential difference between the reference and the sample solutions isqiven by the general equation: E « En + PT/F ln(a! + K..a')
0 1 \l J I
where:r " - a constant related to the reference electrodes and the reference0 solution; "
a^ and a! - the activities of ions i and i, resnectively, in the samniesolution;
K - - the selectivity constant of the harrier membrane.The selectivity constant, K^» an intrinsic prODerty of the barrier membranefor qiven i and j ions, is a function of the ion-exchanne reaction in the inter-ohase and o* the ion mobilities in the membrane nhase .The new electrochemical cell permits the exnerimental determination, of K.•,which in turn provides basic information on the mobility of the liquid ionexchangers' functional groups and the state of aggregation. This is, incident-ally, also a way of rapidly obtaininq data on the selectivity of an ion-exchan-ger for ions i and j.In the present work potentiometric measurements were made on membranes enclosinga mixture of liquid anion and cation exchanqers and a diluent.The effects of the diluent's dielectric constant, the ratio between the anionand the cation exchanger, and of their concentrations, on the magnitude of K..and the oronerties of the barrier membrane were studied.
121
< TGI
HIGH-PERFORMANCE LIQUID CHROMATOGRAPHIC DETERMINATION AMD HYDROLYSIS STUDIESOF PHENYL PHOSPKORODIAHIDATE, A UREASE INHIBITOR
E.R. AUSTIN, T.J. BRADFORD, AND M.S. LUPIN1International Fertilizer Development Center, Muscle Shoals, Alabama U.S.A.1. Present address: Dead Sea Works Ltd, Beersheva, Israel
A high-performance liquid chromatographic (HPLC) method was developed for thedetermination of phenyl phosphorodiamidate (PPDA). This method was employedin a kinetic study of the hydrolysis of PPDA in the pH range of 2 to 12 attemperatures of 2b°, 3bc, ana 45°C. Two parallel competing reactions wereobserved: "The acid-catalyzed reaction produced ammonia and phenyl phosphor-amidic acid; the base-catalyzed reaction yielded phenol and phospnorodiamidicacid. Phenol and phenyl phosphoramidic acid were also determined by HPLC.Apparent first-order rate constants were determined for the hydrolysis of PPDAas a function of pH and temperature. Activation energies of 9.4 and 13.0 kcal/mole were obtained for the acid- and base-catalyzed reactions, respectively.
122
TG2TITLE (CAPITAL LETTcRSi
DETERMINATION OP TRACE HEAVY METALS INTHE DEAD SEA.
AUTHOR'S, irttilutior City, Courr.r,
E.SCHGN8ER6ER, J.KASSOVICZ, A.SHENHAR.THE NATIONAL PHYSICAL LABORATORY OF ISRAEL.JERUSALEM, ISRAEL. '
Traces c * ~ d , L - . v : 3".d Z~ were a e t e T m n e d sr t heDead Sea.T:-.!O d i ^ f e r e r . r ! s s : r o 2 ; ; - s r s . •£.= ^ e ^ s c h o s e n :
D e t e r m i n a t i o n &<•• 3 F H « £ wa* c c r i ^ c t s c . =.ir-=i
t r :e-- - i r suo r . was•:>*" rr.e'-al cheiate* an crsen: ; chase and
u n :n iQutcus phaser APDC-O'I1 .:". . 2-Tr i chic ••* tv; f luor#th*f'e =.yst*r.-.
for ev tract ion.r1.- data ar* giv»n for both ortconctntrat ion
f t t p t ,Control and tr«atrr=er.t of th* analytical blank isde*cr1beo,D e t e T i i i r n t i o n t<\> DPAS'-; Kas- D t r ^o rmed i nJ s c i d »r dn e i j f a i . rosdia on L'eac See samples w h i c h underQoa c i d i c t r e a t m e n t and f i l t r a t i o n .
. '.:^ern ic 3r. 2 ,656.1332.S,^.NURENBtRi3.D.'>l«LEr-n"A;Trace Metals in S»a Water
•"v^T Ce-ference Series IV 1381 ,&£?! .
123
TG3
THE USE OF METAL ADDITIVE IN REVERSED PHASE LIQUID CHROMATOGRAPHY:
STRUCTURE-RETENTION RELATIONSHIPS
A. COHEN, E. 6RUSHKA
Dept. of Inorganic & Analytical Chemistry, The Hebrew University, Jerusalem,Israel.
Nucieotides, nucleosides and their bases, form complexes with the cations when
these are in the mobile phase. Since the nature of the complexes is different
from the parent compounds, their chromatographic behavior changes. The change
can be related to the properties and structures of the complexes. The metal
cations can complex with the phosphate moeity of the nucleotides and/or with the
base part of the molecule. This fact is reflected in the retention behavior of
these solutes. The following Table shows typical behavior.
In the table k1 is a measure of the partition coefficients and hence the reten-
tion tiroes. Mg causes a decrease in the retention of the bases as well as the
nanophosphate nucleotides shown in the Table. This metal is known to be bound to
the phosphate group only. However, the extent of retention change is roughly the same
for all solutes shown. Thus in the concentration range and pH used here, the effect of
the Mg ion added to the mobile phase may be related to changes in the ionic strength.
Similar arguments can be made when nickel ions are added to the mobile phase although
the increase in the retention of adenine should be noted. The use of copper ions gives
different results. Purines are known to complex Cu(II) better than pyri mi dines.
Indeed the retention of adenine and AMP increase significantly whi le that of cytosine
and, to some extent CMP, does not change much. Changes in the retention will
be correlated to physico-chemical properties of the metal complexes.
124
No metalMg(II)Ni(II)Cu(II)Ag(I)
Adeninelog Kf
-N.A.2.47
2.68
N.A.
k1
4.60
4.14.87
9.39
< 20
AMPlog Kf
-
1.97
2.84
3.18
N.A.
k1
2.69
2.44
2.57
3.48
4.26
log
-
N.N.2.
Cytosine
Kf
A.A.0
k1
0.46
0.39
0.49
0.46
1.16
CMPlog Kf
-
1.75
1.9
N.A.N.A.
k'
0.36
0.26
0.32
0.45
1.13
TG4
PSEUDOPLASTIC POLYMER AS A SUPPORT FOR ANALYTICAL SEPARATIONS
oC. GUTTEL, E. GRUSHKA ^Dept. of Inorganic & Analytical Chemistry, The Hebrew University, Jerusalem,Israel.A system consisting of solution of pseudoplastic gel, where the viscositydecreases upon a local increase in pressure or stress,possesses regions ofdifferent chemical potentials. Thus, impurities dissolved in the solution willpartition between these regions. This is the basis of a new purificationmethod. Solutions are prepared from Xanthan Gum and water to obtain a gel withnon-newtonian (pseudoplastic) properties; organic dyes are added as impurities.Xanthan gum is a polysaccharide with a main chain identical to cellulose anda side-chain containing two mannose units and one glucoronic acid unit. Byapplying a shear force, the viscosity of a 2% xanthan gum drops linearly from,100,000 to 100 cps for a shear rate range of 0.1 to 1000 sec'1. The experi-mental setup consists on glass capillary rods inserted into the gel. The rodsare rotated by a motor at fixed speeds; due to the rotation, a shear force isInduced on the gel in the vicinity of the rod and its viscosity drops theresharply. When the rod is rotated the gel starts rising into the capillary,andit contains much less impurities than the bulk. As an example, a pipet havinga 0.7 mm orifice was rotational at 350 rpm for 20 hours in a gel containingmethyl violet; at the end of the shear experiment, the dye concentration droppedfrom 40 to 3 ppm. In the same experimental conditions, methyl orange was foundto be much less rejected than methyl violet. The gel that filled the pipetafter a shear experiment was tested for its integrity by ultracentrifugation,circular dienrolsm and viscosity measurements. The purification process whichseems to occur at the entrance of the capillary has no influence on the struc-ture or molecular weight of the pseudoplastic polymer.
125
TC5
HIGH PERFORMANCE LIQUID CHROMATOGRAPHY OF NONIONIC SURFACTANTS
^ • •• " "• ° -, ft *
N. GARTI, A. ASERINCasali Institute of Applied Chemistry, The Hebrew University ofJerusalem, Jerusalem 91904, Israel n
Surfactants being mostly long chain molecules with botn^hydro-
philic and lipophilic natures are non-volatile and therefore
difficult to elute by gas liquid chromatography. Several attempts
have been made to separate mixtures of the reaction products. The
use of HPLC technique seems to be most adequate for the separation,
quantitation and the internal structure of any given surfactant,
mainly of those applied in the food industry, is of significant
interest, since the health authorities are restricting their use
and require as full an analysis as can be achieved of the product.
This work describes an HLPC separation, identification and
quantitation of four main groups of surfactants: 1. Sorbitan
esters, 2. Polyglycerol esters, 3. Ethoxylated fatty alcohols, and
4. Ethoxylated fatty acids. No derivatization of the compounds
was needed. Improved baseline, in spite of gradient elution, was
achieved by adding negligible amounts of anthracene to the
elements.
126
A . ' TG6
\A GAS POWERED HIGH-PRESSURE APPARATUS FOR THE ACID DISSOLUTION
OF REFRACTORY ALUMINAS FOR TRACE ELEMENT ANALYSIS.
H.A. FONER
Geological Survey of Israel, 30, Malkhe Yisrael Street, Jerusalem, 95501, Israel
Refractory,-single crystal aluminas cannot be dissolved in acids using the
conventional "Teflon" bomb techniques. However, at temperatures and '
pressures higher than those attainable using "Teflon",°the material does
dissolve.
An apparatus is described for the dissolution of refractory single-crystal
alumina. The sample is in contact only with hydrochloric acid and silica.
Samples are sealed in silica glass capsules which are, in turn, placed
inside a steel pressure vessel capable of being heated to 400 °C. Nitrogen
gas is used to supply a compensating pressure (up to 66 MPa; 9,600 psi) to
prevent^the capsules from 'bursting. The apparatus is equipped with means
of measuring temperature and. pressure during the course of the reaction.
Factors influencing the design and safety of the apparatus are described.
,4Jsing transparent high purity vitreous silica capsules and super-pure acid,
• samples can be dissolved for further analysis with minimum contamination.
Small chips of alumina may be dissolved without prior grinding and its
consequent contamination.
It is shown that heating the capsules to above 380 °C slows down the
reaction rate, presumable due to the necessity for the presence of liquid
water to remove aluminium chloride from the reacting surface.
The method is easily adaptable to other types of sample.y•7
•J
127
^ TG7
THE USE OF X-RAY DIFFRACTION TECHNIQUES IN THE CHARACTERIZATION
OF PAPERS FOR FORENSIC PURPOSES
H.A. FONER*, N. ADAN**
-•Geological Survey of Israel, 30, Malkhe Yisrael St., Jerusalem, 95501, Israel••'"'Criminal Identification Department, Police Headquarters, Jerusalem, Israel
The identification and characterization of different types of paper is of
obvious importance in forensic science. One of the more elegant, but less
well-known, ways of doing this is by the use of X-ray diffraction (XRD).
XRO techniques are rapid, non-destructive, and suitable for large or small
samples: ehey form a useful additional method for characterizing specimens
of paper.
The main ccr.situent of paper is cellulose fibre. The degree of crystallinity
of the fibres is a function of both the specific raw material and of
manufacturing process used. Using a specially developed sample support, the
crystallinity of a wide range of papers was measured using the Crystallinity
Ratio (CR) as a yardstick.
CR is defined as:-
C R , 1- \in 1I - I .max minj
where I and I . ' are the intensities of the 22.5°(26) peak and the 19°(29)max nunminimum (Cu K Q radiation) of the characteristic cellulose diffraction
pattern. CR is affected by neither sample thickness nor orientation and is
shown to be a good indicator of paper quality.
In many cases the minerals used as fillers in paper making can be identified
by XRO. It is shown that the mineralogy of the inorganic component of papers
can be a significant factor in thtir characterization.
128
TG8
RAPID ANALYSIS OF PHOSPHATE ROCKS AND RELATED MATERIALSUSING AN ICP SPECTROMETER
D. HOFFER, I.B. BRENNER , L. HALICZGeological Survey of Israel. 30 Malchel Israel St.. 95 501 Jerusalem, Israel
c\ Method is presented for the determination of major^and minor elemets in iphosphate rocks and related materials using an Inductively coupled plasmaspectrometer. Results obtained by this rapid method are compared with thoseobtained by classical means and shown to be at least as accurate as the latter.Up to 100 (dissolved) samples per day may be analysed for major and minorelements. jSimples are dissoved by fusion with LIBO2 using a Claisse - semi-automaticfluxer.Difficulties encountered in the determination of sulphur and sodium arediscussed as well as problems encountered 1n dissolving the sample.The precision and accuracy of the determinations during routine work aremonitored by comparison with International standards.
129
TG9
QUICK AND EFFICIENT r,C LIPID ANALYSIS: jLIPIO HYDROLYSIS AND CONVERION TO FATTY ACIB5
METHYL ESTERS UTILIZING SOLID SUPPORTED REAGENTS.Zvi Cohen
ft Jacob Blaustein Institute for Desert ResearchBen-Gurion University of the Negey
Sede Boqer Campus, Israel
A GC qualitative determination of fatty adds in lipids is a verycommon analysis in industry, medicine and research. However, samplepreparation is a time consuminq process entailing loss of material
and much manual work. Lipid hydrolysis can be achieved utilizingNaflH Imoreanated silica qel. Hydrolysis, purification and derivati-zation is performed quantitatively, without loss of material. Also,the process demands siqnific&ntlv less manual workinq time andenables treatinq many samnies simultaneously.
130
POSTERSESSION WWEDNESDAY. APRIL 11, 1984 ,,
ELECTROCHEMISTRY
THEORETICAL CHEMISTRY
PHYSICAL CHEMISTRY
BIO-ORGANIC CHEMISTRY
PHYSICAL ORGANIC CHEMISTRY
POLYMERS
INDUSTRIAL CHEMISTRY
CHEMICAL EDUCATION
WH1
THE INFLUENCE OF CHLORINE ADSORPTION ON THE ELECTRICALCONDUCTIVITY OF CARBON.
H. TOBIAS and A. SOFFERDivision of Chemistry, Nuclear Research Center-NegevP.O.Box 9001, Beer-Sheva- 84190, ISRAEL
The electrical conductivity (E.C) of an air activated charcaol fiber have beenmeasured during chlorine, dichlorodifluoromethane (freon 12) and propaneadsorption at various temperatures. Unlike freon and propane that had shownno detectable changes in conductivity upon their adsorption, chlorine had aremarked effect which indicated that there are at least two adsorption sitesof this gas on carbon- The very first adsorption doses cause an increase whilelater doses cause a drecrease in the E.C. This implies that the sites respon-sible for the increase in donductivity are the more reactive ones. At lowtemperature, namely 229°k, there is a decrease in conductivity throughout thewhole adsorption range. At high temperatures (723°k) the conductivity increasesthroughout this range. In order to interpret this behaviour it is assumed thatthe reactive sites are populated through activated adsorption that cannot takeplace at low temperatures. Proceeding one further step through this interpre-tation, we suggest that the activated adsorption is chemisorption that involvedisssociation of the Cl2 molecule and saturation of olefinic surface bonds.This is followed by strong physisorption which affects (decreases) conductivityfar more than the physisorption of the "inert" halocarbon and propane molecules.The kinetic behaviour of conductivity upon exposure of the adsorbent to anIncreased Cl2 pressure also supports the interpretation mentioned above: Atintermidiate temperatures, there 1s an immediate and sudden decrease in conduc-tivity during which adsorption, as monitored by the pressure decrease, comespractically to an end. This decrease in conductivity 1s then followed by asignificant increase that takes place at no further adsorption. It seems thusthat reorganization of adsorption sites namely slow activated transformationfrom physisorption to chemisorption takes place upon elapsed time. The depen-dence of the E.C. of carbon on adsorption will be interpreted 1n terms ofthe. semiconductor nature of this adsorption.
133
WII2
CALCIUM/Ca(AlCl4)2-THI0NYL CHLORIDE CELL-EFFECT OF TEMPERATURE
AND CELLS1 PARAMETERS ON PERFORMANCE
E. PELED, E. ELSTER AND R. TULMAN
Department of Chemistry, Tel-Aviv Univers i ty , Tel-Aviv 69978, Israel
The increasing in teres t in safe, high-power, high-energy-density ba t t e r i es ,
has encouraged research on the calc ium/thionyl chlor ide (TC) system. A very
powerful laboratory prototype C-size ce l l has been recently developed in our
laboratory. The ce l l has a C a C A l C l ^ - e l e c t r o l y t e . I t was found that both
the power density and the energy density depend on: act ive electrode area,
cathode Teflon content, cathode poros i ty , and discharge temperature. The
c e l l s ' capacity increases by about 20% at a l l rates by increasing electrode
area from 10U to 130 cm^. The room temperature power density of a ce l l con-
ta in ing an electrode area of 130 cm is 250 W/l while i t s energy density is
above aOO Wh/1. Tnis c e l l del ivers 5 Ah at 0.05 A and about 1 Ah at 3 A.
As tne e lec t ro l y te of th is ce l l contains no l i t h ium cation i t successful ly
res is ts "charging" and reversal abuses. Tne "charging" current a t 25V decrea-
ses from an i n i t i a l value of 150 mA to less than 20 mA in 60 minutes. Simi lar
resu l ts were observed upon reversal of f u l l y discharged c e l l s . Small ce l ls
of l u cm''" electrode area los t about 10f; of t he i r capacity a f te r two weeks of
storage at 70°C. Af ter storage they exhibi ted only minor voltage delay.
Tneir minimum t rans ient voltage at 1.5 mAcm" was above 2 Vo l ts . The e f f ec t
of discnarge temperature on the c e l l s ' capacity is being studied and t h i s
w i l l be presented.
134
WH3
LOW-RATE LITHIUM/SULFUR ORGANIC BAnERY
H. Y /WIN, E. PELED
Oept. of Chemistry, Tel-Aviv University, Tel-Aviv 69978, Israel
The Li-S couple has one of the highest theoretical energy densities, about
2600 Wh/kg. This value is greater by .150% than that of Li/MnO2 and greater
by about 70% than that of Li/SOClg ce l ls . Laboratory prototype button cells
having an SS case and a seal made of a combination of an organic elastomer and
cement, exhibit a high energy density and a ten-year room-temperature
(predicted) shelf l i f e . The electrolyte is 1M LiC104 dissolved in a THF-
toluene mixture saturated with l ithium polysulfide. The polysulfide reacts
with the l i thium anode to form a passivating layer which acts as a solid
e'^ctrolyte interphase (SEI). I ts res is t iv i ty is about 10 flcm. The e.m.f.
of the cel l changes from 2.38 to 2.15V depending on the composition of the
solutions. The energy density of the cel l is 730 wh/kg or 900 wh/kg at room
temperature and 950 wh/kg or 1200 wh/1 at 60°C (calculated on the basis of a l l
cel l components, excluding the case). The goal of this paper is to describe
the effect of temperature and electrolyte composition on cell performance and
on the conductivity of the electrolytes.
135
WH4
APPLICATIONS OF ENSEMBLES OF MICROELECTRODES
H. RELLER, E. KIROWA-EISNER and E. GILEADIDept. of Chemistry, Tel-Aviv University, Tel-Aviv, Israel
Today's technology in microelectronics enables fabrication of ensembles of
microelectrodes in which the diameter of an individual electrode can be as
small as a few micrometers. Possible applications of microelectrodes are in
analytical chemistry, in kinetic studies, in electrosynthesis and in electro-
catalysis. The objective of this work is to evaluate the advantages of micro-
electrodes in these f ie lds.
The advantages of microelectrodes in respect to in f in i te l y large electrodes is
the enhancement of current density, due to increased mass transport by the
radial diffusion component, and the decrease of ohmic potential drop.
From a kinetic point of view, microelectrodes are advantageous only under con-
dit ions in a time scale in which 6(R.,-R )>6>R / 3 , where R and Ro are the
radius of a microelectrode and the distance between the centers of adjacent
microelectrodes, respectively, and f is the width of the diffusion layer. For
very fast electrode reactions (ks>l cm/sec) microelectrodes with R <0.5un have
to be used. The use of an ensemble of microelectrodes for the study of fast
electrode reactions is l imi ted, since currently available pulse techniques can
measure faster rate constants than can be measured with ensembles of micro-
electrodes which have been fabricated so far.
From an analytical point of view,, microelectrodes are advantageous under condi-
tions wnere f u l l overlap of adjacent diffusion layers takes place. The sensit i -
v i ty increases with the fraction of inactive area (area of insulator/total
area). However, Ro-R has to be kept smaller than lOOum to prevent convection
during tne time of measurement. For microelectrodes with R < 0.1 urn, the
detection l im i t may decrease by a factor of a thousand as compared with normal
pulse poiarography.
Enhancement of the l imi t ing current density may give rise to savings inexpensive electrode material in electrosynthesis and electrocatalysis.
136
WHS
USEFUL ARE (PHOTO) ELECTROCHEMICAL METHODS FOR CHARACTERIZATION OF
SEMICONDUCTOR MATERIALS?
JUiiW A. TURNtR1, DAVID CAdEN1'2, BRUCb PARKINSON1, ARTHUR J. NOZIK1
1) So lar Energy Researcn I n s t i t u t e , Golden, CO, USA
2) Weizmann I n s t i t u t e o f S c i e n c e , Rehovot
New, or n i t h e r t o unproven, Materials for o p t o e l e c t r o n i c uses are of considerable
interest to both tne sc ient i f i c and technological communities. Basic research
in materials cnemistry can be aided significantly by adding, to the traditional
structural, elemental and tnermal analysis methods for characterization, opto-
electronic ones, especially for semi conductive materials. iViiile, in photo-
electrocneinical studies on the one hand, and those concerned specif ical ly with
aworpnous or crystalline s i l icon for sol id state photovoltaics, on the other
nanu, soine use nos Deen made of (pnoto) electrocnemical characterization, the
uiifamiliarity of many sol id state chemists and physicists with these methodolo-
gies nas prevented tneir aora general use. This i s , in part, just i f ied ,
because of various types of p i t fa l l s that can be encountered- We will i l l u s -
trate tne usefulness cf (photo) electrochemical characterisation metnods by a
numoer of examples, drawn from several research projects. The conditions that
nave to oe met to enable extraction of useful information will be stressed, as
well as limitations tnat snould' be borne in mind. Tne techniques to be consid-
ered, are - open-circuit potential - illumination; - dark I-V curves; - I-V
curves under white lignt illumination; - capacity-voltage measurements;
- pnotocurrent spectroscopy - bias voltage; - monochromatic I-V curves;
- surface pnotovoltage measurements; - laser scanning and - photocapacity
measurements.
137
WH6
ELECTRODEPOSITED CuInS2 LAYERS AND THEIR CHARACTERIZATION BY PHOTOELECTRO-CHEMICAL METHODS.
T. ENGELHARD, R.N. BHATTACHARYA, D. CAHEN AND G. HODESThe Weizmann Institute of Science, Rehovot, Israel.
g films on Ti substrates were prepared by electrocodeposition of Cu, Inand S from an aqueous bath containing CuCI, InCl3 thiourea, triethanolamineand ammonia followed by annealing in H~S at 400-550°C. Alternatively a Cu-In
2+ 3+alloy was depositedcfrom a Cu and In -containing bath, and this alloy wasthen converted into CuInS2 by heating in an H^S stream at ~550°C. The lattermethod has obvious advantages in terms of versatility with respect to stoichio-metry and type of chalcogen used.Both types of layers were characterized by X-ray diffraction and wavelenothdispersive X-ray fluorescence (microprobe), which confirmed their chalcopyritestructure and stoichiometry in most cases. Some films showed the spinel struc-ture and CuIngSg stoichiometry.The layers showed respectable photovoltaic activity when measured with anaqueous polysulfide liquid junction. Althouqh there were large variationsin activity from sample to sample, quantum efficiencies up to 0.7 were measuredat short-circuit conditions in polysulfide electrolyte. Photocurrent spectrashowed a direct bandgap of ca. 1.42 eV for the layers.
138
WH7
STABILIZATION OF EFFICIENT PHOTOELECTROCHEMICAL ENERGY CONVERSION BY THEn-CuInSe2/AQUEOUS IODIDE SYSTEM THROUGH RATIONAL SOLUTION AND SURFACEMODIFICATIONS.
DAVID CAHEN1'2 and YIH-NEN D. CHEN2
1) Weizaann Inst. of Science, Rehovot2) Solar Energy Research Inst., Golden, CO, USA
n-type CuInSe-, is a very efficient photoanode in neutral, aqueous
polyiodide solution, after etching with 2% (v/v) Br-/MeOH (30 sec) andsubsequent air oxidation at 150°C (3 hours). The chemical etchant removes
a nearly stoichiometric surface layer and the air oxidation leads to In-o
bond formation. To stabilize this system, its electrochemical
decomposition in acetonitrile was studied. (Electro) chemical and surface
analyses are consistent with light-assisted decomposition into the metal
ions and elemental chalcogen. Cu-depletion of the top layers was found
to dominate after decomposition.; A similar effect was found after elec-
trode deactivation in polyiodide. On the basis of these results and those
from solid state chemical studies, indicating an appreciable range of
stoichiometry for this chalcopyrite phase towards Cu-poor compositions, we
succeeded in stabilizing the title system by a) adding Cu ions or Cu and
In ions to the solution and b) by covering the electrode surface with an
extra film of oxidized Indium. Electrodes thus treated, were stable at
short circuit and under optimal load in the modified solution, whileretaining the original conversion efficiencies (up to 11.7% under 120
ii'/cm tungsten-halogen illumination). The success of the solution
modification is ascribed, in part, to the high mobility of Cu ions in this
chalcopyrite. The oxidized Indium layer may well act to passivate defect
sites on the surface.
139
WH8
ENHANCED OPTO-ELECTP.O'.'IC V7IVITY OF SFMIC^'nCfTORS "Y
MEANS OF (PHOTfl)ELFCTRnCHEHICAL ETCHING
R. TENNE, V. fiARCUDept. of Plastics Research, The i'eizmann Institute of Science,Rehovot 76100, Israel
(Photo)electrochemical etching has been extensively used for the reduction of
"l"jctmn-hole recombinations on seniconductor surfaces.
The ooto-electronic activity of various families of semiconductors (both n and
o-tvp-a) such as CH and Zr-chalconenides, oxides, lamellar semiconductors and
ternar1' i»at°rial5 has been considerable/ i^oroved using this surface treatment.
This irproverrnnt is evidenced bw nhotoelectrnchenical neasurercents as well as
'V' F^IC, cathodnluni.iescenc^, ^otoli^inescerce and electroluminescence.
Indications th=it (nhotn'eiectroche^icftl •etchi"r- s°lectivel.w (or preferentially)
attacks s'irf^rp ^tatpr., which are not accessible to rpnular chenical etchants,
come fron electroreflectance, ohntnres-;ons<2 and nhotocanacitance measurements
anH is siio'inrter1 bv c^ intp i " sir.u'istio'i.
( j i c a l etchi^1" leads t'1 rounhpp.inn nx ths semiconductor surface
and a unioue etc!; n i t la t t^rn is exhibited as evidenced bv SEM. This oattern
is attributed t " the non-uniform rlo'..' c* electr ic charges within the space
charge layer.
^resunahly this is caused by the nicroscopically non-iiniform electr ic f ields
•'"lie1"! ?re induce1' bi; the ior.izeH ?nd non-neuzralized dnant ions within the
soace charie la'ye1".
''e have recer.tl" determined the correlations between etch ^ i t density and dop-inq densitv; excitation wav^lenn+h; flrl(j ontenti3.! nf the electrode.
140
WH9
ELECTROCHEMICAL OXIDATION OF TERMINAL ALLENIC HYDROCARBONS
J.Y. BECKER, B. ZINGER
Dept. of Chemistry, Ben-Gurion University, Beer-Sheva, Israel
1,1-Dialkyalallenes undergo two-electron oxidation at Pt anode in methanol
to yield diaethoxylated products. However, at graphite anode and at the
saae potential (1.7V vs Ag/Ag ) the reaction is less selective and products
due to four- and six-electron oxidation were isolated: a, a'-dimethoxy-
ketones and o-methoxyesters, respectively. In acetonitrile-LiC-CO. media
there is always a retention of one double bond and surprisingly the oxidation
takes place favourably at the terminal double bond. When C£0.~ is
substituted with BF4" the products become mainly heterocyclic compounds,
derivatives of pyrimidine, incorporating two molecules of acetonitrile + one
molecule of the allene derivative + one fluorine atom from BF^ .'<
CH,
Pt/2.35V
CH.CH CH_3 y 3CH -CH,
CH
CH, ^ CH,
sec-Bu
sec-Bu sec-Bu
141
1 Nil
ADIABATIC REDUCTION AND QUANTUM CHAOS
G. GOELMAN, M. SHAPIRODept. of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
A method for observing quantum 'regular' states is developed by expanding the N-dimensional exact eiqen-function in the adiabatic basis set. The adiabaticfunctions are separable functions uniquely labeled by N quantum numbers. Belowwe present results for the stadium billiard system (N=2). In classical mechanicsthis system is stochastic for all non-zero values of the aspect ratio AR=a/r (abeing the half length of the straioht side, r beinq the radius of the semi-circle) with the degree of stochasticity increasing from zero at AR=2 (thecircle) to a flat maximum near AR=1 (the stadium). In quantum mechanics thebehaviour is quite different: We found that there exists a transition from'reaular' quantum states at low eneray, to 'irregular' states at high energy.Thus, contrary to the classical case where the system is stochastic for all3nergies, the quantur case it is 'reaular' at low enerny. The degree of regu-larity was judged by the degree of separability, according to the adiabaticreduction, observed. In some cases the overlao of the exact and adiabaticfunctions is essentially 100%. When the seoarability is not complete thenodal lines rather then intersect start repelling each other. These studieswere complemented by wavepacket dynamics: A wavenacket consisting mainly ofthe 'regular' states was nearly periodic, unlike a waveoacket consisting mainlyof 'irregular' states which was shown to soread uniformly in the coordinatesoace.
142
WI2
PERMUTATIONAL SYMMETRY AND SPIN OPERATORS FOR ARBITRARY ELEMENTARY
SPINS.
J. KATRIEL*. J. PALDUS** and R. PAUNCZ** Department of Chemistry, Technion - Israel Institute of Technology,Haifa 32000, Israel.** Department of Applied Mathematics, University of Waterloo,Waterloo, Ontario, Canada.
The well-known one to one correspondence between the piqenstates of
the total spin for spin 1/2-pdrticles and irreducible r-presentetiors
of the symmetric group with up to two rows in the Yca.'ic, shep» is the*
basis of interesting formal developments in quantum chemistry and in
the theory of magnetism. As an explicit manifrstation of this
correspondance the class-operators of the symmetric group erf?
demonstrated to be expressible in terms the total spin'operator, and
some of these expressions are presented.
This correspondence does not hold for higher elementary spins. Thp
extension to arbitrary spin is investigated using Schroedinger's
generalization of the Dirac identity, which expresses & transposition
in terms of two-particle spin operators. It is shown that additional
operators, which for a=l/2 reduce to the total spin, ero needed for r
complete classification. Some aspects of the formalism are developed
in detail for o=l. In this case a classification identical with that
provided by the irreducible representations of the symmetric 'jroup is
obtained in terms of the eigenstates of two commuting operators, one
of which is the total spin.
143
WI5
STRUCTURE REACTIVITY CORRELATIONS IN GATING CURRENTS
N. AGMONDept. of Physical Chemistry and The Fritz Haber Center for MolecularDynamics, The Hebrew University, Jerusalem 91904, ISRAEL
The gating process of ionic channels in excitable (nerve, muscle) membranesinvolves most likely an intramembranal charge transfer process, whose rateconstant depends on the membrane potential i.e., on the process1 free energychange. In the study of structure - reactivity correlations in cnemistry wehave discussed quantitative expressions for the dependence of rate constantson equilibrium constants. It is suggested to use these relations in thestudy of gating currents. One conclusion wnich follows from this analysisof the available experimental data is tnat, in contrast to previous state-ments, tne gating charge is universal (-2.0=0.2) and independent of thebiological species.
144
WI4
A STATISTICAL WAVEFUNCTION MODEL FOR C-H/C-D OVERTONE LINEWIDTHS:APPLICATION TO CgHg, CgDg, CHD5,C6HF5
VICTORIA BUCH, R.B. GERBER AND M.A. RATNER*Dept. of Physical Chemistry & The Fritz Haber Molecular Dynamics ResearchCenter, The Hebrew University of Jerusalem, Jerusalem 91904, Israel•Northwestern University, Evanston, Illinois 60201, USA
Intramolecular energy transfer rates and mechanisms in vibrationally excitedmolecules are of great importance in reaction rate theories, and relevant tothe possibility of mode selective chemistry. The purpose of this research istheoretical interpretation of one of the few existing direct measurements onintramolecular vibrational energy transfer, namely, detailed measurements ofC-H and C-D overtone spectra in several polyatomic molecules (K.V. Reddy, D.F.Heller and M.J. Berry, J. Chem. Phys. 76_, 2814 (1982)). Broad unstructured lineswere obtained in this experiment, with the linewidth determined by intramole-cular relaxation. We explained the following striking experimental results:
a) The linewidth does not grow monotonically with the quantum number (and thuswith the density of states, as suggested by the Golden Rule); it fluctuatesaround some average value, instead.b) Deuterization slows down the relaxation rate out of the bond.c) The CH overtones in CgHFr display anomalously narrow lines. / 1A simple semi quantitative model is presented for the calculation of C-H overtone *spectra in polyatomic systems. The model employs a realistic force field Ramil-tonian that includes the structure of all modes. Approximate solutions for the
eigenstates are constructed, usinn statistical assumptions, on the wave functionsin terms of their expansion coefficients in the decoupled mode basis. The re-sults show, that the centrifugal coupling to the C-H bending motion plays a do-minant role in the broadening process, and yields a simple physical interpre-tation for the observed isotope effects, fluctuations in linewidth with thequantum number anomalously narrow lines of CgHFg, etc. Calculations are presen-ted for the linewidth of CgHg, CgHDg, CgDg, and good agreement with the experi-mental trends 1s found.
145
WJ1
ATOMS AND IONS IN INTENSE EXTERNAL FIELDS
M. COHEN and S. KAISDepartment of Physical Chemistry,The Hebrew University, Jerusalem 91904, Israel
At f i r s t sight, the behaviour of an electronic system which is subjected to a
moderately large external electr ic or magnetic f i e ld is not well described by
means of conventional perturbation theory. This is because the relevant weak-
f ie ld perturbation series are aenerally divergent or, at best, asymptotic.
Nevertheless, with the help of some suitable renonnalisation procedure or
summation technique, the results of high order perturbation theory can some-
times be improved s igni f icant ly , so as to y ie ld precise energy levels and other
physical observables. There has been considerable recent interest in the simp-
lest possible system, namely that of a spinless hydrogen atom in intense mag-
netic f ields with strengths B > 109G (such intense f ields are encountered on
white dwarf stars). We have obtained a good description of this and other one
and two electron systems by using a combination of perturbation theory and
variational techniques, and conclude that judicious use of low order pertur-
bation theory can be competitive with more elaborate calculations.
Garstang, R.H., 1977, Rep. Prop. Phys. 40_, 105.
Avron, J . E . , Herbst, I.W. and Simon, B . , 1981, Commun. Math. Phys. 79_, 529.
146
WJ2
ENTHALPIES OF SOLUTION IN WATER-SODIUM OCTANOATE-ALCOHOL MICELLAR SYSTEMS
A.S. KERTES AND L. TSIHERING
Institute of Chemistry, The Hebrew University, Jerusalem, Israel.
Enthalpies of solution of sodium octanoate in water and its mixtures withn-propanol, n-butanol and n-pentanol, and of the three alcohols in aqueousoctanoate solutions at pre- and post-micellar concentrations were determinedcaloriraetrically at 35°C. The present thermochemical data reveal that thereis a substantial difference in the role alcohols play in these micellarsystems. The standard enthalpies of solution in the ternary systems containingpropanol indicate that the alcohol is not solubilized within the sodiumoctanoate micelle but is part of the solvent mixture. Parallel data in ternarysystems containing either butanol or pentanol suggest the opposite: thealcohols are solubilized in the interior of the spherical aqueous micellesrather than being part of the solvent mixtures.
147
W.J5
PK1 ESSURIZED FL0W DENSIME7 R / - rt NI"' •< i if.L riiJIfIUfc F 0R i':I-: f A I.f-(.1NG I:> -V ••• TPROPERTIES OF L I Q U I D S iVf MOOI-HA 1"F i-i:::F::.SUK'IE.S *--iNL> ?>"fPERrtRJRE"5
S. GLIKBERG, V, HARCUS
Oe=>t. of' Inorgan'.c and Aria.lytxc.3i Chenxstry, The Hebrew University,s-.j, Leu
- ciTMbiri.5 v. t o n o f 3 h i g h - p r e c t ' t i o n l u:> PPM ' v i b r a t i n g f l o w deri s i . Me te r
nd ; he s o l v e n t d e l i v e r y sys t i -m o f ::ri MIH.C t n ' . : t r u i i e n t p e r m i t . - t h e
. l e f l - i i i r e n e n t o f t h e neiv:.). t y o f L i q u ' . d s arid - s o l u t i o n s :ss a f u n c t i o n
• : * i i e t e m p e r a t u r e w i + he pi <:••'•:suv;•••>> <'in HPI..G i^oiumn I r i s e r l « d i r i t h e
; t h o f 1-.,e I. ;'-i«i'i-1 r-ehi n«.i '/"•.'•- I O - M I , or '. it-: i.ieri .11.-; ,-'>e:.JS
! 1';?:: '. he ' •>?•:: i. ^ ' . -•*!" •.. t» t o I'I ow i i- i. r t "d f'ui i r ie 3t+;:i.MiMerit >.)f "n. qn
. ._ ^ , - , ' - , t ft , , •••
i ' i '• ••. T I ft'4i'3t'or o r : i t j t ; : > - I ' M I 11'- .1 c ?~e , . f -io I. u l i i s r i s ::• f o i . i r t n
• i ; . 1 " j ; o d d t > . ' « i - ' . i . L n r - > , I U U C ' I V ' I • • ! i i i. e : >.» i ' i u J u t e p e r V t o l e o f
•I ' .MI!. i ) t T i v * U ' > ("I.; :sr.t ; t Le-- :"<:.h _•••: ;.ht» i / i o b ^ r t i : t h e r m a l expan-
1 •• : . • !'•:• i .-o+.term"'i compreT-.-, i n i I. i t ••;• or the i n t t ' r n a l p r e s s u r e
• ,"if-: i i. •"!•..';. d or t he c o r ' espoi id J. nq i->«.r t i a J. n o L i r l u a n t t t i e s i n t h e
<•• r • ">o !.i_«t :i on •??•*. t ne i i reccj i .'.'.••• ob t s \ r ied > An I n t e g r a t i .on o f the
I ' l f ' ^ ' s t n ' ^ ? c o e f f i f . lent .'if thi? ;.-.,:w t J. ~ I moi. <:;r vo].i.ipte o f t r a n s f e r o f
• • ' • • - >ei,weeii tuo -•:•:!•.• en 1. :. wi. t n r e s p e c t t o the p r e s s u r e . Detween
• ' I-.-, i i-i.» .j. pre-;: : ; " res or the :M | , ; e n t 5 <:>••; l i m i t s , s h o u l d y i e l d t h e
• i • • . . I i-)oi":»r e n t r o p y o f t r ans t i-r >>(• t h e :=oJuteJ
/ . P ( i n » 5 2 ) >::1'-' | ; ": - j i -AV' I''.-.QP
P( i . r . ,S l . ) l
,e hitjn pr(?cj = ion of the data obtainable with the instrumentation
=: prerequisite for applying this novel method for obtaining the
itropy of transfer from density data,
-suits are presented for methane It ?»cetonitrile» and aqueousy
>dium chloride solutions,, as 3n illustration for the application
this technique*
148
WJ4
HYDROGEN ATON AND ELECTRON TRANSFER IN FLAVIN TRIPLET INDUCEDPROTEIN CIDNP.
T. WISMONTSKI-KNITTEL AND K.A. MUSZKATDept. of Structural Chemistry, The Weizmann Inst i tu te of Science,Rehovot, Israel
Tr ip le t dye induced nuclear magnetic polarization in proteins (protein photo-
CIDHP) depends on ri atom or electron transfer as the generating process of the
t r i p l e t electron spin correlated radical pairs. Taking part in these processes
are tne side chains of tne three amino acids tyrosine, histidisie and tryptophan.
In order to check the va l id i ty of several basic assumptions of photoCIDNP for
studying side chain exposure and structure of proteins as well as protein-protein
binding we have investigated the three CIDNP active quenching orocesses of t r i p -
le t 10-carboxyetftyl f lav in F by tyrosine, hist id ine and tryntophan as well as
tne quenching Dy the CIDiJP-inactive metnionine (a l l studied as the N-acetyl
derivatives). At pri 7, the rate constant of quenching of F (k » in M~*sec )
reaches almost di f fusion controlled values for tyrosine and tryptophan (3.95 x
10 and 1.08 x 10 , respect ively) , . is s l i gh t l y lower for methionine, 0.3 x 10 ,q
and signi f icant ly lower for h is t id jne, 0.06 x 10 . Oxidized glutathione wasfound to oe devoid of quenching ac t iv i ty . Similar quenching react ivi ty trendsare ooseryed under other conditions (e .g . , in 67% sucrose solution or in 30"water ethylene glycol at room temperature and below). Tha activation onergies<ire 4.2 Kcal/mole for tyrosine, 3.6 for tryptophan ano a much higner value,
i.& Kcal/mole for nist id ine. Under a l l conditions examined we could not detect
any difference in quencning mechanism -jetween tryptophan and methionine on one
nand and tyrosine and hist idine on the other. We could not obtain any evidence
for participation by a ^ery fast stat ic quenching process. The consequences of
these results for the correct interpretation of protein CIDNP results w i l l oe
discussed.
149
KJ5
THE SYSTEM BOVINE SERUM ALBUMIN-ALIZARIN YELLOW G.THERMODYNAMICS AND KINETICS OF BINDING
B. PERLMUTTER-HAYMAN, E, NISSANIDept. of Physical Chemistry, The Hebrew University of Jerusalem, Jerusalem,Israel
The ability of proteins to bind various small molecules plays a decisive role
in their biological function. Of Darticular interest is the fact that these
small molecules can induce structural changes in the protein, a shenonenc
which leads to cooperative binding. The system bovine serun albuir.in-alizarir
yellow G was investigated as a model system for this behaviour, "he alburn
was found to oossess six strong, and a number of weak binding sites for tnis
dye, with stronq positive cooperativity between the *irst and subsequent bind-
ing sites, as evidenced by a very pronounced maximun in tne Scatch^rd -Mot.
Using a simplified mathematical model, we were able to obtair, expressions *or
six equilibrium constants in terms of three independent bindinc narameters mea-
sured by equilibrium dialysis. The question whether the coooerati'vitV is one to
the pre-existence of various confomers or to "liaand induced fit" was answered
in the investigation of the kinetics of the binding. In the stooned f:o^ .ona-
ratus, the first steD was found to be diffusion-controlled, an^ was followed by
a slower rearranoement. This shows that a conformational 'change in the albumin
is not a condition for binding to take olace; rather, it is the bindinq o^ the
first ligand that causes the change In the kinetic experiments - both in the
stooped flow and T-jump apparatus — in additional, even slower transformation
was observed at low saturation o-f the albumin. We ascribe this transformation
to a side reaction, since it is not rate-determining for the formation of high-
er comol exes, but disappears at higher saturation. After the binding or the
first ligand is completed, additional binding takes olace at a di^usion-con-
trolled rate or nearly so. These results are in good agreement with the *"act
that both the spectrophotometric pronerties and the values of &u and A?0 cf
the first complex differ significantly from those of all the rest.
!5O
i_ .. -J
WJ6
KINETIC ENERGY RELEASES BY TIME-RESOLVED MAGNETIC DISPERSION
S. GEFEN, C. LIFSHITZ
Department of Physical Chemistry, The Hebrew University of JerusalemJerusalem 91904, Israel
A new type of multidimensional mass spectrometer has been presented by Enke and
coworkers. We have employed a similar technique, namely time-resolved magnetic
dispersion, to determine kinetic energy releases in unimolecular dissociations
of polyatomic cations. The arrival time at the collector is not only mass-depen-
dent, but also different for ions formed in the source and during f l i g h t . Ioni-
zation by electron impact is pulsed and ions are stored for a variable delay
time in the ion-source by an electron space charge. Time-dependent kinetic
energy releases were obtained from metastable peak shapes for the reaction,
CgHgOH* •*- C-CgHg- + CO in phenol. The new technique allows to distinguish bet-
ween kinetic energy releases of stat ist ical origin ("non-fixed" energy release)
and those due to reverse activation energy.
J.T. Stults, C.G. Enke and J.F. Holland, Anal. Chem. 5£, 1323 (1983).
C. Lifshitz and S. Gefen, "Time-Dependent Mass Spectra and Breakdown Graphs.The Kinetic Shift in Phenol", Org. Mass. Spectrom., in press.
R.G. Cooks, J.H. Beynon, R.M. Caprioli and G.R. Lester, "Metastable Ions",Elsevier 1973.
151
KJ
UNIMOLECULAR DISSOCIATIONS OF POLYATOMIC PHOTOIONSAT NEAR THRESHOLD ENERGIES
Y. MLINOYICH, G. HASE, A. ARAKAWA and C. LIFSHITZ
Department of Physical Chemistry, The Hebrew University of JerusalemJerusalem 91904, Israel
We have developed the technique of°Time-resolved Photoionization Mass Spectro-
metry (TPIMS). Pulsed ionization in the VUV produces photoions which are
trapped for variable times in a Cylindrical Ion Trap (CIT) before being ejected
for mass analysis. The method combines excellent energy resolution with time
resolution and allows determination of time resolved appearance energies of
fragment ions under constant sensi t iv i ty conditions. Experiments have beer,
carried out on iodobenzene, pyridine, ani l ine, ethyl benzene, cy,clo-octatetraene
(COT) etc. Energy-entropy trade-offs are being assessed for unimolecular disso-
ciations of polyatomic cations. The s tat is t ica l nature of the reactions at near
threshold energies is beino assessed through deuterium labell ing experiments.
Specific rate coefficients k(E) * 1 sec"^ may be observed through computer
control and accumulation of the data. Evidence for transit ion state switchincs,
between t ight and orbiting transit ion states, is being sought experimentally.
C. L i fsh i tz , M. Goldenberg, Y, Malinovich and M. Peres, Org. Mass Spectrom. 17,453 (1982).
J.E. Fulford, R.E. March, R.E. Mather, J .F . J . Todd and R.M. Waldren, Can. J .Spectrosc. 25, 85 (1980).
M.T. Bowers, M.F. Jarrold, K. Wagner-Redeker, P.R. Kemper and L.f-\ Bass, FaradayDisc. 75, in press. .-,, ,,-
— \> //
152
WJ8THE EFFECT OF N0 2 GROUP ON THE IGNITION DELAY TIMESOF STRAIGHT AND CYCLIC HYDROCARBONS
ASSA LIFSHITZ, SHULAMIT BARZILAI-GILBOA "Dept. of Physical Chemistry, The Hebrew University of Jerusalem, Jerusalem,Israel
Ignition delay tines of cyclopropane and of three hydrocarbons containing oneNO2 group: nitromethane, nitroethane and nitrocyclopropane were measured overa wide temperature range and were presented in comparison with ignition delayof the same hydrocarbons without the nitro group. These experiments were per-formed in order to examine the effect of the NO2 group on the oxidation rateof cyclic and strainht hydrocarbons. The experimental results reveal threesignificant features. 1. The nitro-aiiphatic compounds are nuch more reactivethan the corresoonding hydrocarbons, judcini from the duration of the ignitiondelay at a given temperature. 2. Contrary to aliphatic hydrocarbons, the in-crease in the nitroaliphatic concentration, causes a decrease in tne ignitiondelay times. 3. The spread of the log T VS. 1/T curves amono the -NO2 con-taining substances, is considerably smaller than the one corresponding to theignition of the simple hydrocarbons. There is a good correlation Detween theinitiation rates and the i<jnition delays of the six fuels in question. It issuggested that the opening of a new avenue for initiation, namely, rupture ofthe weak C-NOg bond increases the oxidation rate.
153
WJ9
THE REACTION OF CATALASE WITH ETHYLHYDROGEN PEROXIDE
Mordechai L.Kremer, Department of Physical Chemistry,
Hebrew University, Jerusalem, Israel.
The change --if the optical absorption upon the addition of ethylhydrogen
peroxide (ROOH) to a solution of catalase (E) passes through a maximum
over a range of initial [ROOH], at a constant initial [E] (Brill and
Williams, Biochem. J.(1961) 7<8,253). This behaviour indicates the presence
of a precursor /E»ROOHJ to compound I (C.) formed in the system, and a
reaction of this precursor with a further ROOH molecule.
The reaction scnerae is given by
E + ROOH—; [EROOH\
C —=-r fc+RCHO+H.,0
£EROOH] + ROOH — ^ [ E • (ROOH) X
The last species may be actually a biperoxy complex or an inactive
product of the reaction between the constituents of this complex.
154
WJ10
THE MECHANISM OF THE DISMUTATION OF SUPEROXIDE CATALYZED BYCu(II)-PHENANTHROLINE COMPLEX AND OF THE OXIDATION OFCu(I)-PHENANTHROLINE COMPLEX BY OXYGEN IN AQUEOUS SOLUTION
S. GOLDSTEIN, G. CZAPSKI
Dept. of Physical Chemistry, The Hebrew University of Jerusalem, Jerusalem,Israel
2+The cata lyt ic properties of Cu(II)-phenanthroline complex, (op)9Cu , upon the
disproportionation of superoxide radicals, generated by pulse radio lys is , have
been investigated. I t has been found that (op)?Cu catalyzes superoxide dis-
mutation through a "ping pong" mechanism which opperates between Cu(II) and
Cu(I) s imi lar to that of superoxide dismutase. The "turnover" rate constant,kcat = ( 5 « 1 ± 0 « 9 ) 1 0 8 M'^s"1, has been determined. The kinet ic results of the
oxidation of (op)pCu+ by molecular oxygen in aqueous solution are interpreted
by a mechanisn which proceeds via a superoxide intermediate..The redox poten-
t i a l of the complex (op^Cu^* has been determined to be E° = -0.055V. The i n -
terest in this mechanism arises from the sensit izing effect of (op)?Cu2+ on
DNA damage under i r rad ia t ion in vivo and in v i t r o . We have also studied the
ef fect of the addition of DNA on the catalyt ic ac t i v i t y of (op)pCu2+ upon
superoxide dismutation.
155
WJ11
SOLUBILIZATION OF PARAFFIN GASES IN AQUEOUS SOLUTIONS OF SODIUMDODECYL SULFATE
A. BEN-NAIM, J. WILFOept. of Physical Chemistry, The Hebrew University of Jerusalem, 91904,ISRAEL
The solubilities of methane, ethane, propane and n-butane were measured in
aqueous solutions of sodium dodecyi sulfate (SOS) of molar concentrations
between 0-0.15M (The cmc of SDS being at about 0.008M). The measurement^
were repeated at six temperatures between 12-27 C. From these measurements
we have computed the standard free energies, entropies and enthalpiesi fior
the process of transferring the gas molecule from the gaseous phase into
the aqueous surfactant solutions. All gases show an abrupt change in their
solubility at the cmc. The slop of the solubility curves is larger the
larger the size of the solute molecule. We have also noticed a significant
shift in the cmc caused by the presence of butane molecules.
156
V
WJ12
AFFINITY LABELING OF ELECTRON TRANSFER SITES ON BLUE COPPER PROTEINS.
P. Frank, A. Licht, 0. Farver and I. Pecht.Dept. of Chemical Immunology, The Weizmann Institute of Science, Rehovot 76100,Israel.
The chemical properties of the Cr(II)/(III) couple have been successfully
employed to affinity label electron transfer loci on redox proteins. Being
strong reductants and exchanging fast their ligand sphere, Cr(IT) ions can
coordinate one or more of the surface residues on a redox protein while reduc-
ing it. As the produced Cr(III) is substitution inert, any protein residues in
the coordination sphere of the Cr(II) during the electron transfer will remain
bound to the Cr(III) product. Identification of the Cr(III) binding site has
then been achieved primarily through proteolytic cleavage of the labeled
proteins. Spectroscopic methods have also been employed for corroborating
these assignments. Several single blue copper proteins have been examined by
the above approach. These include azurins, (pseudomonas and alcaligenes),
plastocyanins, (French bean and poplar) and stellacyanin (Rhus vernicifera).
More recently we found that even the multicentered blue copper oxidase-laccase
can be reductively labeled by this procedure.
The cuprous ions in the Cr(III) labeled plastocyanin, azurin and stellacyanin
could be fully reoxidized by inorganic or enzymatic agents. While the single
Cr(III) ion originally coordinated to azurin and stellacyanin remains bound
through several Cr(II) reduction and reoxidation cycles, one can label plasto-
cyanin with several Cr(III) ions in repeating redox cycles. The analysis of
the Cr(III) labeled sites on plastocyanin and £s_. azurin showed that electrons
proceed via the His 35 region in azurin (Az) and near the negative patch on
plastocyanin (Pc). To examine whether the latter electron transfer sites are
also involved in the biochemical function of these proteins, their reactivities,
in the native and Cr(III) labeled forms were compared. It became apparent that
the Cr(III) label attenuated the reactivity of both azurin and plastocyanin
with only one of their respective two partners. This led to the conclusions
that on both proteins: (a) There are probably two distinct and physiologically
operative electron transfer sites, (b) One of these sites is centered around the
respective Cr(III) labeled region, (c) By elimination, the second is at theexposed, homologous imidazol of His-87 or 117 in Pc and Az respectively.
157
WJ13
pH IMPENDENCE OF THE RESONANCE RAMAN SPECTRUM OF BILIRUBIN
M. TOPOROWICZ , A. YOGEV , L. MARGULIES +
* Isotopes Dept., The Weizmann Institute of Science, Rehovot, Israel+ Dept. of Soil § Water Sciences, The Hebrew University, Rehovot, Israel
Bilirubin (BR) is the degradation product of heme in liver, which under chemi-
cal modification is excreted in urine. Deficiencies in this catabolic process
in newborns cause excess of BR in blood (neonatal jaundice). Irradiation of
the patient witti Blue light lowers the BR level, due to a change in the solu-
bility properties of BR as a result of a Z-E photoisomeri^ation. This photo-
reaction break? some of the six li-bonds present in the original BR molec ule
(Z,Z configuration) leading to more soluble photoisomers which are efficiently
excreted by the liver.' Resonance Raman spectroscopy was proven to be useful
for studying bile-pigments in solution.2 The dependence of the resonance
Raman spectrum of BR on the pH of the medium has been studied in order to get
insight into tne vibrational modifications induced by the presence of intra-
molecular H-bonds in this molecule. Resonance Raman spectra in neutral chloro-
form and in basic aqueous solutions were recorded exciting with the 5145A
line of an Ar laser. In basic aq. solutions, H-bonds are broken leading to
tiie carboxylate anion. Outstanding differences are observed between the two
spectra regarding relative intensities and frequency shifts. Some bar.ds
appearing in one of the spectra are absent in the other showing that different
species are present in media with different acidities. These effects are
reversible. The data obtained by resonance Raman spectroscopy is comple-
mented by measurements done jsing uv-absorption and fluorescence techniques.
The indications of these results on the analysis of resonance Raman spectra
of natural biliproteins will be discussed.
Lamola, A.A., J. Flores and F.K. Doleiden. 1982. Photochem. Photobiol.,
55, 649.2Margulies, L. and M. Stockburger. 1979. J. Am. Chem. Soc., 101, 743.
WK1A STRUCTURAL MODEL FOR THE ACETYLCHOLINE RECEPTOR
E.M. KOSOWERDept. of Chemistry, Tel-Aviv University, Tel-Aviv, Israel andDept. o-f Chemistry, State University o-f New York, Stony Brook,N.Y., USA
Thetransfersynapses.tried torequiredeffect iveillustratedpept ide
acetylcholine receptor (AChR) is an important link in theof information at neuron-neuron and neuromuscularTo delve into the structure and mechanism of the AChR, Ianswer a simple question: If conformationai change isto produce a biological effect, what is the smallestchange? Our choice was single group rotation (SCR),
by the motion of a side chain around the cc,^-bond to aA plausible receptor site was organized around
acetyicholine (ACh>, using (-> groups for the trimethylammoniobinding site (glu~ or asp"), a < + )-hydrogen-bondi ng group -for theester carbonyl (lys*) and a <-) group to "pin* the <•) charge.Single group rotations in the ACh and the lysine side chain at thereceptor site led to an open space large enough for. a hydrated Na*ion, which might correspond to "gate" opening for the ion channelof the AChR. Placing a pinning <-) group near the lysine after SGR,connecting the first pinning <-) group to the second pinning <->group via a polypeptide chain which includes the lysine, and then
the polypeptide as an oc-helix revealed a set of chargedgroups along one side of the a-helix. This sequence is astructural arrangement for an ion channel: an a-Helix
ng charges, lys* glu~—lys 4... This theory wasQuantum Biology meeting in 1982. Shortly thereafter,
arrangingside chainplausiblewith alternatpresented at aJapanese, French and American research teams presented the completeami no acid sequences for the five subunits, a*fti, of the receptor.The predicted sequence was found in the a-subunit (a373-391>:lys* glu~—lys + g l u T — l y s + glu~ and thus identified a* afunctional element, an ion channel element. Enough hydrophobicgroups were present in the sequence to ensure that the helix wasamphiphilic and suitable for a membrane bilayer location. Criteriafor ion channel elements were a length of 24 ami no acids, at least3 lys*—glu~(asp~) combinations and amphiphilic character. We found2 channel elements in the a-Subunit, and 1 each in the P-, Y- andt-subunits. Many sequences (28) contained such high percentages ofapolar %id* chains that they were classified as hydrophobic bilayerhelices. The amphiphilic helices which constituted the ion channeland the hydrophobic helices could be combined into a partialstructural model for the AChR which had a mass distribution (exo-cellular, membrane, cytoplasmic), a shape, an oc-helical content,and a location for the ion channel which corresponded to what wasknown. The theory also leads to an exobilayer model with two morebinding sites (ACh, local anesthetic), a channel opening toxinmechanism, a plausible bacterial chemoreceptor channel, and to amolecular theory of olfaction.
159
WK2
STERBOCHEMICAL ASPECTS IN CHLOROPHYLL BIOSYNTHESIS
A.L. GUTMAJJDept. of Cheaistry, Technion - Israel Institute of Technology, Haifa, Israel.
Studies with doubly labelled Xaainolaevulinic acid (ALA) have established the
absolute stereochemistry of the enBymatic processes by which the ubiquitous
ethyl group of chlorophylls is formed from a vinyl group of protoporphyrin IX,
an earlier biosynthetic precursor.
Tn<? synthesis of (2S)-'_2-~n, .-'H, 'ALA made use of a phenylselenyl derivative of
monomethy] suecinate. The selt-niur. not only activated the adjacent hydrogen for
eisy replacement, by -'H :>t high levels of specific activity, but also allowed
ready conversion of Uic "xcheaged product into monoraethyl[2-yH funarate, which
WHS enzymn-icaily r-.-iuc-a witi, ?-enoate raductase in D-,0 to yield raonomethyi
.;v, "^ -_2-£"H1,-H,; '.•>-" H '3Uc:inatv-. This was cnen converted chemically into
ALA inrrying ~H and -'K *sotopt-s st C-2 in the ^-configuration.
Incorporation of this .-ihi' il ALA by cells of Rhodopsfeudomonas spheroides into
Dicteriochlorophyl I _a_ p-oduced the methyl group of the ring-B ethyl residue in
chiral form, whilt incorporation of ;')-'HjALA generated the methelsne group of
the ring-B ethyl residue in chirai form. Appropriately labelled samples of
bn-teriochiorophyli _a w:r-- degraded ir such a way that the ring-B ethyl group
was isolated -is either (3R)-.[";-'1H< , 'H1 jpropionic acid or (2S)-[2-'lH1'.'propionic
said. The configuratior. of the former was established by converting it without
racemization into the corresponding acetic acid, whose chirality was determined
by assay with malate synthetase and fumarase. The configuration of the
[2-^H^propionic acid w s determined by assay with transcarboxylase.
S60
WK3
NOVEL TOPOCHEMICAL NON-PSPTIDIC ANALOGS OF SUBSTANCE P
Eli RUBINI*, Chaim GILON**, Uri t/ORMSER*, Zvi SELINGER* and Michael CBOB5V*^Department of Pharmaceutical Chemistry, **Department of Organic Chemistry, and*Department of Biochemistry, The Hebrew University of Jerusalem, Jerusalem,
Israel
Topochemical equivalence between a chemical structure and a known drug agonist
may lead to the reproduction of its effective interaction with the appropriate
receptor. A well known case supporting this concept is the morphinomimetic
activity of the endogenous opioid peptides, the enkephalins, which interact with
the same receptors as the natural and synthetic opiate alkaloids. The applica-
tion of this concept to substance P (SP), a putative peptide neurotransmitter
in the central and peripheral nervous system is the subject of this paper.
Conformational analysis of substance P and derivatives (I) based either on
empirical force field calculations or on spectrometric and spectrophotometric
methods resulted in the suggestion a several closely related low energy confor-
mations. Examination of these conformations lead to certain topochemical models
which we have attempted to reproduce using hydroxyprclinc (Hyp). The hydroxy-
proline unit, a small rigid ring carrying three different functional groups, is
used as a framework on which the essential pharmacophores of substance P can be
attached in a particular spatial arrangement leading to a molecule with a certain
topochemistry (II). The availability of three different isomers of Hyp, i.e.
trans-L, cis-L and cis-D together with chemical manipulation of these structures
provides us with frameworks which offer a great variety of substitution patterns.
In this work we report the design, synthesis and biological activities of the
first generation of novel non-peptide analogs of substance P.
pGlu-Phe-Phe-Gly-Leu-Met-NH
p „. W pGlu-Phe-N | (II)
[pGlu
CO-Leu-Met-NH^
1. R.A. Nicoll, C. Schenker, S.E. Leeman. Ann .Rev .Neurosci., 3_, 227-68 (1980).
2. P. Manavalan, F.A. Momany. Int.J.Peptide Protein Res., 2Q, 351-65 (1982).
3. F. Inagaki, T. Miyazawa, N. Yanaihara, M. Otsuka. Proc. 15th Symposium on
Peptide Chem.Japan, p. 103, 1977.•r
161
WK4
THE CONFORMATION OF GUANABENZ , AN ANTIHYPERTENSIVE DRUG
A. GOLOBLUM1 , S. COHEN2 , S. DIAMANT3 , D. ATLAS3 and I. AGRANAT*Departments of 1 Pharmaceutical Chemistry, 2 Inorganic and AnalyticalChemistry, 3 Biological Chemistry and 4 Organic Chemistry, The HebrewUniversity of Jerusalem, Jerusalem 91904, ISRAEL
Guanabenz ( I ) is an orally active central a2-adrenoreceptor agonist.effectivein lowering blood pressure*. It is devoid of various troublesome effects ascompared with its prototype drug, clonidine ( II ). Guanabenz, synthesizedfrom 2,6-d1chlorobenzaldehyde and aminoguanidine, gave monoclinic crystals( from H2O ) , space group P2i/C, with unit cell dimensions a= 16.29 8 ,b= 8.31& , c«7.49 R , e'= 98.34° , Z= 4 , RB 0.035. The aromatic 2,6-dichlorophenylring and the methyleneimino-guanidine moiety are each planar within experim-ental limits. The X-ray structure reveals the non-orthogonality of the aromaticversus the guanidine moiety, with an angle e= 39.7° . This structure does notfit a previously suggested model2 for clonidine type activity, based on X- raystructures of clonidine and related drugs. Semiempirical quantum mechanicalcalculations of clonidine and guanabenz in their basic^and protonated formsshow that clonidine is rotationaly restricted with respect to guanabenz .Clonidine, guanabenz and protonated guanabenz adopt orthogonal conformationswhen their geometry is totally optimized by the method of modified neglectof differential overlap ( MNDO ). By the same method, protonated clonidine ^adopts a non-orthogonal conformation with P= 60° . Biological studies show
that guanabenz is not selective in its adrenergic activityclonidine , guanabenz proved to be a significant 6-blockerits a2-adrenerg1c affinity.
— N H 2
to
to
( I ) ( II )1B.Holmes,R.N.Brogden.R.C.Heel J.M.Speight and G.S.Avery, Drugs 26, 212 (1983)2A.Carpy,J.M.Leger,G.Leclerc,N.Decker,B.Rouot and C.G.Wermuth, Mol.Pharmac. 2 1 ,400 (1982)
162
WK5
PARTIALLY MODIFIED RETRO-INVERSO [Gly3f(NHCO)Phe4]-ENKEPHALIN ANALOGS -SYNTHESIS, CHARACTERIZATION AND BIOLOGICAL ACTIVITY.
No#my GILON*, Dina TEITBLBAUM-LOYAN**, Batia ACKERMAN+, Marta WEINSTOCK-ROSIN**,Eli RUBINI*, and Michael CHOREV*Dept. of Pharmaceutical Chemistry*, Dept. of Chemistry**, Dept. of Anaesthesia1"and Dept. of Pharmacology++, The Hebrew University and Hadassah Hospital,Jerusalem, Israel
In an attempt to further explore the biological potential of the novel topo-
chemical approach in the design of partially modified retro-inverso analogs2 3
of endogenous neuropeptides such as enkephalin and substance P we haveprepared the following analogs :
H-Tyr-Gly-NH-CH2-NH-CO-CH(CH2-$)-CO~Leu-NH2, and
H-Tyr-D-Ala-NH-CH 2-NH-CO-CH (CH^) -CO-Leu -NH2
Preparation of the gem-diaminoalkyl moiety was accomplished by a rearrangement
of the corresponding Boc-dipeptide amide employing iodobenzene bis(trifluoro-
acetate). This modified dipeptidic unit was coupled to (RS)~2-benzylmalonyl-
leucine amide yielding a pseudotetrapeptide in which the reversed isosteric
amide bond was formed. Deprotection of the Boc group followed by coupling to
Boc-Tyr-OH yielded after removal of protecting group the above mentioned1 °
analogs. High resolution H-nmr, FAB-ms and amino acid analysis were used to
characterize the final products. Kinetic measurements of the configurational
stability of the analogs was studied employing RP.-HPLC. Biological activities
of the new analogs determined both in-vitro and in-vivo are related zo thex'1 -
structural modifications.
1. M. Goodman and H. Chorev. Acc.Chem.Res., 12, 1-7 (1979).
2. M. Chorev, R. Shavitz, M. Goodman, S. Minick and R. Guillemin. Science,
204, 1210-1212 (1979).
3. M. Chorevr E. Rubini, C. Gilon, V. Wormser, and Z. Selinger. J.Med.Chem.,
28_, 129-135 (1983).
163
KKfc
A MODEL STUDY FOR BACTERIORHODOPSIN AND VISUAL PIGMENTS
M. SHEVES, N. FRIEDMAN, T, BAASOV
Department of Organic Chemistry, The Weizmann Institute of Science, Rehovot,Israel.
Visual pigments consist of a chroroophore, 11-cis retinal, covalently bound to
an apoprotein, opsin, via a protonated Schiff base linkage. The absorption
maxima of visual pigment from various sources varies from 44C r.r. to 600 nm.
Similar regulation cf the absorption maxima exists in the r urple membrane cf
Hzl?bx?zeriw~: hulcbC^n which absorbs at 560 nir.. Understanding of the mechanisr.
through which the protein regulates the absorption maxima of various pigments
is one rf the r.ort intriguing problems in vision chemistrv. Series of retinal's
analogues carrvin-; r.oiv-conjucateJ positive charges were synthesized in order to
check the shift m the absorption maxima of protonated retinal Schiff base
induced by electrostatic interaction through srace. It was found that positivs
charge= caused a Dlue shift0in the absorption maxima, the magnitude of which
varied according to the location of the positive charge along the retinal
polvene. Positive charges also affect the C=C stretching hand of protcnated
retinal Schiff base, and the thermal isomerization of various retinal isomers.
WK7
mil HI-MOLYTIC ACTIVITY OF T-2 TOXIN
K. SI-GAI. AND I. GOLDZWEIJ
Dcpt. of Natural Products, School of Pharmacy, The Hebrew University
of Jerusalem.
T-2 toxin is one of the wore widely distributed highly positions 12, 13 -
epoxytrichothecenes, giving rise to a great variety of toxic symptoms. It
has been alleged that trichothecene toxins have been used in chemical
warfare in South East Asia as "yellow rain". The great diversity of its
noxious manifestations suggests a non specific mechanism. Using red blood
cells as models for investigating T-2 toxin toxicity its hemoiytic properties
were examined. Tests with different concentrations of T-2 toxin showed that
essentially complete hemolysis of rat erythrocytes commenced after a lag
period the length of which depended on the concent tat ion of toxin. Comparison
of the characteristics of hemo lysis caused by T-2 toxin, saponins, H.,0 and
polyoxyethylene surfactants showed great similarity between T-2 toxin and
the latter two which proceed by a free radical mechanism. The same mechanism
is suggested for hemolysis caused by T-2 toxin on the basis of the additional
following observations:
1) darkness inhibited hemolysis;
_') antioxidants and specific free radical scavengers, i.e. vitamin E,
mannitol.histidinc and glutathione, inhibited hemolysis caused by T-2 toxin.
165
WK8
SEVEN DIFFERENT CHEMOTYPES OF ARTEMISIA HERBA ALBA ASSO FROM THE NEAR MIDDLE
liAST
R. SEGAL*, L. EDEN*, A. DANIN**, H. DUDDEK***, M. KAISER***.*Dept. of Natural Products, School of Phamacy, The Hebrew University
**Dept. of Botany, The Hebrew University, Jerusalem***I>ept. of Structural Cheaistry, Ruhr University of Bochum, Germany
Artemisia herba alba (Composite) known as the "desert wormwood" is
characteristic of the steppes of the Middle East and North Africa. It is widely
used in the folk medicine as an anthelmintic, for relief from cough, against
intestinal disturbances, colds, etc. Seven different cheniotypes of this plant
have been discovered in the near Middle East, on the basis of the differences
in their scsquiterpene lactones (Table). The broad range of therapeutic effects
ascribed to the plant may be explained by the existence of several chemotypes.
composition of Sesquiterpene Lactones in Various A.
Site of Growth Sesquiterpene Lactonc
!. Sede Boqer
J. Mizpe Ramon
3. .UuUaii Desert(Maale Aaos)
4. liulean Desert(AJon road)
l.lat
Sinai
Kas 111 Hikma
herba alba populations
Q Reference
herholule A. (0.003°,,)herbolide B (0.02'.)herbblide C (0.0021!.)
herbolide A (0.16',.)herbolide B (0.015*.)herholidc- C (0.0016V)deacetylherbolide A (0.02"u)herbolide D (0.021.)
herbolide E (0.017*1herholidc F (0.03*.)
herbolide E (0.21Jherbolide F (0.03SVIherbolide G (0.2"*)herho'lide )\ (0.01°,")herbolide I (0.211.,)
l lf-H-tatridin V3-oxo-ll;-H-tatridin I)llnt-H-gaJlicin
santonin
et al.Phytochem. 16, 1237(197?). —
Segal et alPhytochem. 22, 129(1983). ~~
Gordon et al. J.Nat. Prod. 44, 432(1981).
Khafapy et al.Planta Medica 20,90
166
WK9
INTERACTIONS BETWEEN ACIDIC PROTEINS AND CRYSTALS: A STRUCTURAL APPROACH
TO ELUCIDATE PRINCIPLES OF BIOLOGICAL MINERALIZATION.
Lia Addadi* and Stephen Weiner*** * *
Departments of Structural Chemistry and Isotope ResearchThe Weizmann Inst i tute of Science, Rehovot 76100, ISRAEL
Skeletal hard parts are generally formed by the growth of crystals within a
structural organic framework (the "organic matrix") which is composed
primarily of proteins and polysaccharides. The macromolecules in direct
contact with the mineral phase, are primarily proteins rich in acidic amino
acids. These are thought to interact with calcium ions at the crystal
surface, by means of complexation with the amino acid side-chain carboxylate
groups. We have investigated, ha VAAHO, the mechanism of interaction ;
between acidic proteins extracted and part ia l ly purified from mollusk shells,
and growing crystals of various model compounds of calcium salts of
dicarboxylic acids. The results obtained indicate that the Ca-bound proteins,
adopting the s-sheet conformation, interact with specific surfaces of the
growing crystal . These are characterized by having the carboxylate groups
emerging at the face oriented such that they can complete the coordination
polyhedron $ f protein-bound calcium ions. Similar stereoselective interactions
can be recognized on the faces of biologically formed crystals of calcite
and aragonite. The acidic polysaccharide-rich fractions of the mollusk
matrix did not influence crystal growth in any observable way.
167
WK10
SYNTHESIS AND BIOLOGICAL ACTIVITY OF PSEUDO(KETOMETHYLENE) AND BESTATIN LIKE
ANALOGS OF SUBSTANCE P.
A. EWENSON*, R. LAUFER**, H.(cHOREV*, U. WORMSER**, Z. SELINGER** and
C. GILON*. *Depart»ent of Organic Chemistry, **Department of Biochemistry
and #Depart«ent of Pharmaceutical Chemistry, The Hebrew University of Jerusalem
Jerusalem 91904, Israel
The following pseudo(ketomethylene) and bestatin-like CD analogs of
Substance P were prepared as potential inhibitors of Substance P degrading
enzymes: ^
1 pGlu-{RS)Phe-iHCOCHV> fRSJPhe-Gly-Leu-MetNH.,
I pGlu-Phe-(RS)Phe-.:'(C0ClU)Gly-Leu-MetNllo
3 pGlu(2RS,5S)AHPA-Phe-Gly-Leu-MetN]l,
£ pGlu-Phe-(2RS,5S}AHPA-Cly-Leu-MetNH.,
>AHPA = 5-amino-2-hydroxy-4-phenyl-butanoyl
Preparation of the pseudopeptidic units was achieved by a modified Dakin-West
rearrangement (2i of the O-acylation product of benzoyl phenylalanine
oxazolone and tiie appropriate succinyl mono-ester mono-chloride. The latter
was prepared by a modified Stubbe condensation. The free pseudopeptidic unit
obtained after acidic hydrolysis was protected (Boc) and incorporated into the
hexapeptide to yield ana Ions 1 and 2 having an isosteric ketomethylene bond
instead of an amide bond. AHPA was prepared according to (51 and incorporated
into the hexnpeptiilos to give analogs 5 and 4. Peptides were characterized
by H NMR and amino acicl analysis. Their biological activity and inhibitory
effect on Substance P degrading cn:>iiies were assessed.
(1) il. Umczawa, T. Aoyagi . !!. Suda, M. liamada and T. Tekenchi, J. Antibiot.
29, 9" (1976).
(2) N. Engel and IV. Steel it-h, Ann. 1P1(> (197S) .
(51 R. Nishizawa, T. Saino, T. Takita, !l. Suda, T. Aoyagi and II. Umezawa,
J. Med. Chem. 20, 510 (1P77).
168
WK11
SYNTHESIS AND STRUCTURE ACTIVITY RELATIONSHIPS OF NOVELPOTENTIALLY ACTIVE ISOSTERS OF ADRENERGIC DRUGS
A. NUDELMAN, S. BERGERDept. of Chemistry, Bar-Ilan University, Ramat-Gan 52100, Israel
A novel family of ethylene-diamines X» bioisosteric to the known adrenergicethanol-amine drugs, has been prepared by three alternative procedures. Twoof these synthetic approaches were used in the preparation of derivatives
possessing primary or secondary R" alkyl groups, whereas the third method was
also suitable for the synthesis of tertiary R" alkyl products.
I k. Ar-Qi-CH2NH2 Ar-CH-CH,-NH-R"NH-CH,-Ph NH PH Ph '
4 2 NH-CH2-Ph NH-CH2-Ph
Ib \
0 Ar-CH-CN Ar-CH-CH2-NH-R"
C * 2
Ar-C-H NH-C-CH, -*• NH-C-CH • Ar-CH-Qi -\HR"" n 3 I ^
\
n0 0
is
Ar-CH-CN Ar-CH-CO_H _^ ° ^ "' - • i 2 — • Ar-CH-C-r«R" - • Ar-CH-C-NHR"NH NH | i
^ l NHBOC !«,
The biological, in vitro, agonist-activity of the products, was evaluated by
activation of the enzyme adenyl cyclase and measurempnt of the resulting
increase of cyclic-AMP. Structure activity relationships, indicate that the
most active derivatives were those possessing a benzyl R1 groups (Ib).
169,
WK12
CARBOHYDRATE-BASED SYNTHESIS OF 3(R)-HYDROXY-5(R)-
(2-HYDROXYETHYD-TETRAHYDROFURAN
DANA KJAER. SHALOM SAREL, NELLY KOLODNY
Dept. of Organic Chemistry, Technical University of DenmarkDept. of Pharmaceutical Chemistry, Hebrew University of Jerusalem, Jerusalem,Israel
For a project aimed at synthetizing a 14-membered ring ant ibiot ic macrolide
gram quantities of the hi terto unknown chiral system, 3(R)-hydroxy-5(R)-(2-
hydroxyethyl)-tetrahydrofuran (6) was needed. Towards this end, we designed
a selective radical di-deoxygenation of the easily available 1.4-anhydro-D-
glucitol (sorbi to l ) . We wish herewith to describe a faci le five-stage syn-
thesis of (6) following the sequence 1 * 2 > * 3 > - * £ I > 5 I - * 6 . « in good y ie ld .
f)
°Vr
WS
U)o
t»)
r£)"SIC
^ ° '
170
WK13
SWTHETIC ION CARRIERS PATTERNED AFTER NATURAL COMPOUNDS
ABRAHAM SHANZER AND JACQUELINE LIB MAN, Department o f Organ ic Chemistry,The Weizaann Institute of Science, Rehovot, Israel.
In an attempt to provide artificial ion carriers for transition metalions we synthesized two series of conpounds which are based on thestructural principles of two naturally occuring iron carriers: entero-bactin and nocardamin. These two types differ in their structures andtransport modes.
Enterobactin No card w i n
While enterobactin is a tripode like molecule where the side chains (ca-techol residues) serve as binding sites , nocardamin has i ts bindingsites (hydroxamates) incorporated into its ring skeleton. Moreover, en-terobactin serves as 'one way shuttle' (it decomposes into its constitu-ents after penetration into the ce l l ) , nocardemin as reversible carrier.
Structural analogs of both types of compounds have been prepared. Usingan array of different functional groups as binding s i tes , llgands suit-able for transition metal ions other than iron have been obtained. Theconformations and binding characteristics of these molecules will be de-scribed and compared with those of the natural compounds.
171
KK14
60 MINUTES IN THE LIFE OF NEUROSPORA CRASSA
L.O. ZAMIR and K.A. DEVOR, Chemistry Department, McGill UniversityI n s t i t u t Armand-Frappier (Universi ty du Quebec)531 des Pra i r ies B lvd . , Laval-des-Rapides, Laval (Quebec) Canada H7M 4Z3
WP are applying a k ine t i r -pu lse label ing technique in order to determine the
deta i led steps in the biosynthesis of phenylalanine and ty ros ine. The novel
metabolites arogenate and spiro-arogenate have recent ly been discovered in a
mutant of 'ieurospora crassa (Zamir et al_., J . Am. Chem. Soc. ]_C2, 4^99 :198c);
J. 2 i o l . Chem. _?5B, 6486*6492 (1983)). Is arogenate pr ior to spiro-arogenate
in the metabolic pathway? or is the reverse true? A k inet ic-pulse label ing
technique whereby you feed radioact ive spec i f i ca l l y labeled shikircic aci^
and iso la te the intermediates at d i f f e ren t time in terva ls should give the
answer. We w i l 1 also describe the synthesis of spec i f i ca l l y labeled
shiki i ' i ic acid at C-J, ~-4 and C-5.
*s
1
WL1
THE N-ACYLIMINE AND THE N-ACYLIMINIUM CATIONS;BARRIERS TO ROTATION AMD
HOMO-LUMP CONTROLLED REACTIONS ; AN AB-INITIO INVESTIGATION.
A. S t a n g « r , Y. A p e l o i g
Department of Chemistry, Technion - Israel Institute of
Technology, Haifa 32000, Israel.
The T'-Aeyliirnne f i ) nr.rt thr *'-Aey] ir,ii*iiuri ion
i r soirr syr+beser of ^ i jk
, i sco ' j i ' io lcrp d^ri e t c . "« driver ti,"»*eri 1 bv '.irinf
ir- r nrv r*n l l ' - r r . ' ns r-orfonr"^ by -ni ?.
b f t r ^ i w r u r o n protpr^lJOT 1 . ^ ^ B H I * ? r * ( i r T>o1«irir,h*ioT; o f •tVr> TT r.yp+«^<* b y *•>-<•
posi t ive charge, ^h^ rencrionr. ?** J_ "f"1 £ f i . « . r r e l s - ' l r tp r , r?3fnrror>"51i,*
sr^ ru r l eo rh i 1 i r ntter 'rs) srp •irl».'lys*»'1 by P.*'.C. theory. *' ' :? four'' **•«>* 1
does not r^act ir a riiene. ?, on the oth»>r bard, -?ue to i*'s lov HT?'C
^n^rpy, r*bc+t> a? «t diore Kitr "rpv«r!""f p ipct ro i ic rtennn'!''. /ip r lec + ro-
phi l ic »tt.?ck on 1 would tn^e plnce on tb» n i t rorer ratbor +har on the
r . A nunl^ophi^ic «ttnck vovli* take nlroe on the !»C carbon both nn ^
2.
173
WL2
THE EFFECT OF NEGATIVE CriARGH DELOCALIZATION
OH THE EFFICIENCY OF TUL tlcB REACTIOH
S. HOZ, Z. GROSSDept. of Cnemistry, Bar-Ilan University, Ramat Gan b210U, Israel
In carbanionic elimination reactions, tne carbanion can be stabilized by acti-
vating groups which differ in their ability to delocalize the neighboring neg-
ative cnarge. The effect of the degree of delocalization on the expulsion of
the leaving group was examined.
In order to enable a fair comparison, two activating groups which Droduce car-
banions of tnt sauc staoility were cnosen. Tvvc cyano groups representing the
localizing grouos (&•,& nidloncnitrile 11) and a single nitro group (pKa CH3N03
10.I) as a model for the delocalizing groups were employed to give the
systems shown below.
It was foam that tne carbanion derived from ]_ was greatly superior to the one
derived fro... £ in expelling tiie leaving groups (X = OHe, CN}.
Since tiie localizing nature of t\\c CU group is not directly inferred, an at-
initio calculation at a 4-JIG level was performed. It was found that the
cyano group largely localizes the charge ootn at the TT level and overall on
tae carbon whereas in the nitro group the charge at both levels is largely
shifted to tne oxygen atoms.
174
WL3
A ao-HAMMETT STUDY OF THt Q~2 MEDIATEDOXIDATION OF DIARYLHETHANES
A.A. FRIMER, T. FARKASH-SOLOMONDept. of Chemistry, bar-Han University, Ramat-Gan 52100, Israel
A good deal of research has been carried out on the 0l induced oxidation ofhydrocarbons.1'2 Lee-Ruff and Tinms3 have recently reported that 0^ mediated
autoxidation of fluorene and diphenylmethane proceeds via an initial benzylic
hydrogen abstraction by superoxide (equation 1 and 2). Simple thermochemical
c
°2 •
R " H
R . n
H RH
h °2h 0
— • HOO-
— • R« H
— • RO»-
+ R
+ RH — • HOO" + R. (1)
R« + 0,, —o R02' U)
4calculations, however, cast serious doubt on the role of superoxide as ahydrogen abstractor, except perhaps with exceptionally labile hydrogens.Alternatively, in light of superoxide's impressive effective basicity, amechanism involving 07 induced base catalyzed autoxidation (equations 3-5) is
(3)
(4)
(5)
more l ike ly . Indeed a Hammett op plot for the reaction of 0" with various
substituted diphenylmethanes gives a p value of 4. A kinetic isotope effect
k^/kjj « 2.3 was also observed. This data confirms the suggestion that depro-
tonation (equation 3 ) , not hydrogen atom abstraction (equation 1 ) , is the
rate determining step.
References
1 . A.A. Frimer in "Superoxide Dismutase", Vol. I I , L.W. Oberley, ed. ,Chemical Rubber Co: Boca Raton, Florida, 1932, pp. 33-126.
2. A.A. Frimer in "The Chemistry of Functional Groups: Peroxides", S. Patai ,e d . , Wiley-Intersdence, New York, 1983, pp. 429-461.
3. E. Lee-Ruff and N. T1mms, Can. J . Chem. 58, 2138 (1980).
4. J.F. Liebman and J.S. Valentine, Israel J . Chem., 23, 0000 (19<33).
175
WL4
A SHIFT IN THE THRESHOLD MECHANISM OF CORRELATED ROTATION IN2,2-DIMESITYLETHENOLS FROM A ONE- TO A TWO-RING FLIP
D.A. NUGIEL, S. E. BIALI and Z. RAPPOPORTDepartment of Organic Chemistry, The Hebrew University, Jerusalem, Israel.
The methyl region in the H NMR spectra of 2,2-dimesitylethenol (1_) in acetone-dg at 198°K and of its 1-tert-butyl analogue (2_) in CgD5CD3 at 185°K show sixsinqlets, indication frozen propeller conformations.
(i3) Mes x X P
(B1) M e s x ^OH1 : R-H2 : R=t-Bu
Upon raising the temperature the two pairs of o_-methyl ciroups and the two pairsof aromatic protons of 1_ coalesce. Different barriers were found for the ex-channe of diastereotopic oroups (o-Me or aromatic protons) in the two rinqs. Forthe f'-ring AG_* =10.4 kcal mol"1 and for the e-ring AG * =14.2 kcal mol . In
± -1
contrast, only a sinole AG + value of 10.4 kcal moi was obtained for thecoalescence of either the £-Me or the aromatic protons of the1 two rings of 2 .Me ascribe these differences to different threshold mechanisms for the enantio-merization of these two blades vinyl propellers. The threshold mechanism for }is A [;-']-one rinn flip which exchanges the two pairs of diastereotopic groupson the i';'-rina with a AG* of 10.4 kcal mol" , but not the diastereotopic groupson the e-ring. This process is accompanied by a second process with AG* of
"14.2 kcal mol which interchanoes these groups on the --rinn and is likely tobe a [ii,.- ']-twe-ring flip. The identity of the barriers for the 6- and thei'-mesityl grouos of 2_ which reside in diastereotopic environments suggest thata [c,.-']-two ring flip is the threshold mechanism for ,2. This is corroboratedby the similar behavior of the a-methyl analogue of 2 . The shift in the rota-tional mechanism from a one-rinn flip in 1 to a two-ring flip in 2_ is rational-ized by steric effects: The bulky tert-butyl group hinders the Dassage of the6-ring through the molecular plane. These are the first examples of one- andtwo-ring flips and of a substituent-dependent shift in the threshold rotationalmechanism in the series of 1,1-diarylvinyl propellers.
M
176
WL5
REACTIONS OP HEXAMETHYLBENZENE WITH O(3P), 02(*A ) AND O3 ON SOLID SUPPORTS
E. ZADOK, S. RUBINRAUT, F. FROLOW AND Y. MAZUR
Dept. of Organic Chemistry, The Weizmann Institute of Science, Rehovot, Israel
Microwave discharge of Mixture of He with O2 or CO2 produces 0(3P) atoms and
02( A ) rrolecules. At low temperatures (-78rC), in contact with silica gel or
florisil, ozone is formed and accumulates :.n the solid support. \t 0ec,
h«xamethylbenzene adsorbed on solid supports reacted to giv? 1_, whil« at -78°C,
2/ 2 *nd 1 were isolated.
The mechanism of these oxidations will be discussed.
177
WL6
OXIDATION OF AROMATIC COMPOUNDS WITH O(3P) ATOMS: RADICAL VS. ELECTRONTRANSFER MECHANISM
E. ZADOK, S. HtJBXNRAUT, Y. MAZUR •
Dept. of Organic Chemistry, Weizmann Institute of Science, Rehovot, Israel
The reaction of methyl benzenes with 0(3P) atoms results in phenols derived
from both C-H and ipso substitution. In liquid phase, at 0°C or higher/ ipso
attack results mainly in methyl cleaved ohenols, formed via a diradical inter-
mediate. In liquid phase at low tewneratures, or on adsorbed Dhases, an electron
transfer process takes, place, resulting mainly in methyl migration products.
0(3P)
178
WL7
NOVEL 4nir POLYCYCLIC SYSTEMS: HKTEROCYCLIC DI AN IONS
Yoram COHEN, Abraham MINSKY and Mordecai RABINOVTTZ , r>'
Department of Organic Chemistry, The Hebrew University of Jerusalem, Jerusalem,
91904, Israel
Polycyclic hydrocarbons which belong to the (4n*2)ir series can be reduced
to the respective dianions. These dianions are 4mr systems and therefore
antiaromatic. Their paratropic nature depends on the HOMO-LUMO energy sat).
The energy gap is inversely proportional to the paratropicity of the system
which is also influenced by the ion salvation equilibrium. Surprisingly,
there has not been any reports on polycyclic anions which contain hetero atoms.
The reduction process of benzo[c]cinnoline (,11 and related polycycles with
sodium and lithium metals affords the respective dianions. These dianions
show the expected paratronicity and an unexpected temperature dependent
H NMR spectrum. The low field shift of the lithium compound relative to
the sodium analog is rationalized in terms of covulent vis a vis ionic
contributions. A variable temperature LH and °C NMR studies lend strength
to this conclusion and rules out ion -olvation equilibrium as an explanation
for these observations.
179
WL8
THE REACTION OF METHYL SUBSTITUTED ANTHRACENES WITH ALKALI METALS
Ron FRIM, Abraham MINSKY and Mordecai RABINOVITZ, Department of
Organic Chemistry, The Hebrew University, Jerusalem 91904, Israel
Anthracene derivatives e.g. 9-methyl- and 9,10-methyl-anthracene undergo a
metal reduction process to form the corresponding 16* conjugated dianions
accompanied by the formation of the respective benzyl anions. The 4mr
dianions exhibit paratropicity while the benzyl anionic species do not. The
reduction process depends on the reducing metal. Sodium metal reduction of
the anthracene skeleton affords deprotonation of the methyl groups as well
as a two electron reduction process of the polycyclic moiety. The two
species are formed concomitantly. No tetra-anions were observed. The
reaction with potassium metal yields only the deprotonation product. We11have shown previously that the appearance of the H NMR spectrum of
conjugated systems depends on the H0M0-LUM0 energy =gap of the dianion which in
turn allows a singlet-triplet equilibrium in these systems. In 9,10-dimethyl-
anthracene the effect of the triplet state anions present is deci*eased.
\
l(
ISO (\
:\
WL9
PARATROPICITY AND ANTIAROMATICITY: ROLE OF THE HOMO-LUMO ENERGY GAP
Abr*ha» MINSKY and Mordecai RABINOVITZ, Department of Organic Chemistry,
The Hebrew University of Jerusalem, Jerusalem 91904, Israel
Doubly charged systems derived from fused benzenoid polycycles reveal an
unquenched delocalization of 4m electrons and hence are predicted to possess
antiaroaatic character. The magnitude of the paratropic H NMR chemical
shifts due solely to the paramagnetic secondary field sustained ir. these
species, was found to depend linearly upon the magnitude of thel'JMO-HOMG
energy gaps of the corresponding .systems. The very existence' of such a
correlation enables a comprehensive treatment of the various factors which
determine the antiaromatic character and the subtle interrelations between
those factors. This, in turn, enables a deeper understanding of antiaroma-
ticity. Dibenzotetracene dianion^ shows HNMR patterns which indicate
the existence of a partitioning of its MO's into two parts: "anthracene-like"
iiid "phenanthrene-like" systems which exhibit independent characteristic
features similar to those observed in the anthracene and phenanthrene dianions.
This phenomenon is expressed much more profoundly than just a mode of charge
distribution. It can be rationalized in terms of a'minimised antiarometic
character, a state which leads to a smaller energy content.
•'/r
isi
V\
WM1
POLYSULFIDE GRAFT POLYMERS AS POLYMERIC REAGENTS
A. DOMB and Y. AVNY, Department of Organic Chemistry, The Hebrew University
of Jerusalem, Jerusalem 91904, Israel.
Sulfur containing graft polymers may be of interest as polymeric transfer
agents. Graft polymerisation of propylene sulfide on crosslinked polystyrene
beads was investigated. Crosslinked polystyrene and its chioromethyiated
derivative were grafted. Crosslinked polystyrene was lithiated by.i SuLi-TMEbA
and used to initiate anionic graft polymerization of propylenr sulficie.
Grafting on chioromethyiated polystyrene was achieved by reaction of its
chloromethylene groups with sulfide groups of preformed polypropylene sulfide
and by reaction with terminal sodium thiolate groups of living polypropylene
suJfidc. Graft polymers of high sulfide content (10 mmole S/g) were obtained.
Morphology changes and polypropylene sulfide distribution in the grafted
polystyrene beads were investigated. These graft polymers were converted to
their borane complex and used successfully for reduction of aldehydes, ketones,
carboxylic acids and esters. Asymmetric reduction of ketones, in low optical
yields, was achieved by the use of optically active graft polymer borane
complex.
is:
WM2
REACTION-." Z~ C3? 713^7:.J jD OP
for 2he":iot.r\" ->.n:' X.e-iCc-1 "2en~GuTioa "niverclty of the I!e£ev,3eer
Charit : Israel ?iber Institute,Jerusalem
Three !;in^3 of low—density polyethylene v^itli different value
of deacity ma rielt flow iiiclex -.vere usec* f^r t-o productive':
cf f i b e r s .
rroduced r iber t wero cxv ects." to t'-e --j.1.;soci-'!ori--- t i n a.t--"
cince:-r>ent ••y0roly.de w.'tt. t'.ie p-.r.^orje o:r> pi'-.-.uci'i' 7-';?--
:Jlie r e su l t : , o.'.1 t :O L"c:;e:.:rc:i of :.v*t.>r.-3""tj.e." ?,.:' ~J~vn':uv•: ,J~.
i a i t i - ' J vs-/- t r ca teo f iber, ; J.-...^:i•••-,-.tc."1 t:.^5 T?~.-\}. :I C" . . .
v'C;;-cti,?ii-abi.lit" f;,-.c" the ^tr^ir.^'TG :•" f loor. . . '
'Z'he ch.'_ij.fc,."j of -r-'tructv.j.*s dv.r:i..." c..e:".ic.~.l ti^s'". t • o ;;' .' i ; v? • : \
jvited v/ii". T-rn.r r.-U? DJ.7 :iistpcdr ) de">en' vy? i: . i t i ?. . -ui'u•'.••-
t:,;re of fi"ier-.».
j/he c:>vrnj"- ^ " iecli^-aanl ,:.?'6';-r.rti.-G Df f i b c v (c ' -r ; ._•} -- -. •"
elon;':atio;i-v.;luo.' -.- iv s^^ec ia l ly tho for.i of .:vr? : - : ' : • •'!.::
curvet"' e.-r/. ;-c e:;.5lai:ied i'i t ' i3 ter ' iu of the • c v ^ e t i M ^ ^7tv/o ;proce.-.-'e-.,: the * lo rp .asa t icn of i n i t i a l rtr\n"-.t-"'v c.j-:i
f . e oros;- - l i h.C \r of v o lye t ' ^ le i ie O.nri-.ir chersi?.?.! t r s r t p c r . t .
is?
WN1
UMNIUM RECOVERY FROM PHOSPHORIC ACID WITH SELECTIVE RESINS
S. BELFER, E. KORNGOLD, Y. EGOZY
The Institutes for Applied Research, Ben-Gurion University of the ttegev,Beer-Sheva, Israel
A solvent process for the recovery of uranium from phosphoric a d d was CMnercia-
11zed and I ts application has been expanded signif icantly. Our objective was
to evaluate the feas ib i l i ty of recovering uranium from phosphoric add with
selective resins. Uranium-selective resins were prepared in a single operation
by adding a synergistic mixture of diethylhexytphosphoric acid (DEHPA) and
trioctylphosphine oxide (TOPO) as a selective extractant to vinyl and polyvinyl
monomers and polymerizing the mixture. Several hydrophobic and hydrophilic
monomers were used, and the relationship between the composition of the poly-
merizing mixture, the morphology of the polymers formed, and the performance
of the resins in columns were studied with the aim of finding the best
conditions for resin preparation. I t was found that the,extractant acts as an
inert diluent that modifies the three-dimensional polymerization process by a
phase separation mechanism and leads to the formation of a porous structure,
which 1s very important for good kinetics. A high amount of extractant mixture
(60%) and a high concentration of crosslinking agent are necessary for prepa-*
ring a resin with good mechanical s tab i l i ty and kinetics. The resin was tested
in a column 190 cm long with a raw brown phosphoric acid obtained from Negev
Phosphate Co. The average uranium concentration in the eluent (4.4-4.8 g/1)
was almost 30-fold higher than in the raw acid (0.15 g U / l ) . The decline 1n
capacity* which was attributed to the loss of extractants, was less than 5%
for a contact of 1000 l i te rs of acid per kg of resin. The economics of the
recovery of uranium from phosphoric acid with selective resins relat ive to that
with solvent extraction is due to the lower cost of the pretreatment step,
because of advances in the technology for continuous ion exchange for treating
effluents containing suspended matter, and to the lower txpense of the txtrac- .
tants.
1*4
HYDROGEN SULPHIDE DIFFUSION IN AVIATION TURBINE FUELS AND
ITS INFLUENCE ON STORED FUELS
A.B. SHAVIT*, J. BEN-ASHER**
* "DELEK" The Israel Fuel Corporation Ltd., Tel-Aviv, Israel.
** The Israel Institute of Petroleum and Energy, Tel-Aviv, Israel.
The influence of hydrogen sulphide diffusion on Stored Aviation Turbine Fuels
(AVTURS) and its corrosive effect h*s been studied. H2S diffusion froa tank
aqueous bottom into the stored AVTUR phase is a rapid process. Neat AVTURS,
without antioxidants, in comparison with conventional inhibited AVTURS tested
in an experimental diffusion coluan, had a diminishing effect on the stored
fuel's corrosivity. H.S evolution from an aqueous solution, simulating possible
Sulphate Reducing Bacteria action in AVTUR storage tank bottoms, was suppressed
by proper pH adjustment. It has been established that elemental sulphur corro-
sion depends on the actual sulphur configuration. Elemental sulphur in an eight
atom ring structure, at a certain concentration has even an inhibiting effect.
It may be assumed that only atomic sulphur causes synergistic corrosion effects
with H2S in fuels.
,7
115
WN3
STKEMSTS OF UTEX G i ^
O . S H E P H l f # K.SHEPSLEV, K.KSIRT
Kir U t , libbutt Nir Os, Kerer, Israel.
u'In previous works 1t has been shown that the syneresis of latex gels cannot \
o -be ^escribed by the equation of the reaction of the first order. The
empirical eauatlon which rare a rood approximation to experiment wa?
Th#» ^nvestiratior .->f **•«•« worV-? 5how*-: that the water exuried r*vrirr the
•yr«*r»!«*«r pr.^ser^ WT? *aker. as the unit o* mea^urer'er't. Ihi? i s nfsiea^jrr
«"»re* 4 t ** obrr<r>';« tra* only a v?ry snail part of the, water ir the f f i i s
eorneeted by so2v*tior forces tc the surface of the
Tr *!•• rresert work the unit of neasurenert of syneresis was th« fr«e y
-•? the rlobules, which was ecreasirr •iurinr the process. The authorf
d at equation? cf +he reaction for eel? with different iritial
e""cartra*-*or!- and *t different temperatures.
a
'.' v?.5 e»4abl*Rhe'< that the syrerecis rroeess f i t? the equstior. of the
<"**»e*iors' ^r^er •• *h*orp*icallj' qccri""!TT *"> ">* ''T.~ O*""^.* This i F i;e tc
»"J< •4 rra: rrsr««sec o^evrirr, SK?}- ae th» Irteractior of ' v f a c * active ••<
arert? Wth eoafnlarts, or th<» rrevert:nr bv water of ful l roalescer-ee of
186
WN4
ETHYLENE DIAMINE FROM ETHYLENE DIMOMIDEI. SYNTHESIS
L.N. SHOW, J. SEGALL AND Z. BLUTSTEINTAHI (INI) - Institute for Research I DevelopmentHaifa 31002, POB 313, Israel
The synthesis of ethylenediaMinc together with Its homoiogues: diethyienetriacine, tricthylene tetramine, etc. fro* ethylene d1bromide (EDB) and aqueous•wonla Is described and compared to the conventional process using ethylenedichloride (EDC). EDB Is converted quantitatively under wilder conditions:relatively low temperatures, 75-95°C, and within short periods of time, 15-30minutes, to products of similar compositions to those obtained In the conven-tional EDC process. Other competing processes using more expensive rawmaterials such as monoethanolamine or ethylene oxide, require higher tempera-tures and pressures, and produce a different, less desirable product mix. Anadditional advantage of using EDB Is that the bromine it carries 1s recoverableas valuable CaBr2.
187
) <-•
WN5
ETHYLENE DIAMINE FROM ETHYLENE DIBROMIOEII. PMOUCTS SEPARATION \
J. SE6ALL. L.M. SHOW AND Z. BLUTSTEINTAMI (INI) - Institute for Research a DevelopmentHaifa 31002, POB 313, Israel
A novel solvent extraction process 1s described for the separation of ethylenediamine, together with Its homologues: diethylene triamine, triethylenetetramine, etc. from the aqueous reaction product containing these amines astheir hydrohfUdes. Two different approaches are described:
- extraction of product ethylene amines after neutralization with lime, bysubstituted phenols of Intermediate acidity, pKa > 7.5, followed by backwashof the extract with water at a temperature above ambient,- extraction of hydrogen bromide prior to neutralization of the product, bystrong amines, pKb < 4, whereby the product ethylene amines remains in theaqueous solution, and the amine hydrobromides after treatment with lime,regenerate the water insoluble, solvent amine, leaving the CaBr2 product as anaqueous solution.
188
WN6
POTASSIUM SULFATE ROM POTASSIUM CHLORIDL AND PHOSPHOGYPSUM.
THE INFLUENCE OF PHOSPHOGYPSUM STRUCTURE ON ITS REACTIVITY.
L. KOGAN AND M. AIZENBUD
IMI (TAMI) Inst i tute for Research & Development L td . , Haifa, Israel .
A process tor the production of potassium suifate from potassium chloride
and phosphogypsum in concentrated aqueous ammonia solutions has been studied.
The reaction rate was found to be dependent on the weight rat io of aqueous
anmonia solution to phosphogypsum and on the size and structure of the
phosphogypsum aggregates. The morphology of the different phosphogypsum
samples was examined by the scanning electron microscope, in an attempt to
relate the morphology to the reactivity of the phosphogypsum samples. The
differences in the crystal habit are due to major differences in the reactor
design of the phosphoric acid plants, and are also a function of the mixing
regime and of the additives' nature and quantity. 95% conversion to K2S04
was obtained after two hours with elongated trapezoidal plate- l ike phos-
phogypsum aggregates (10-20y x 50-70p , 5V thin) composed of very thin
needles. Only 75% conversion was obtained at the same conditions with
dense rose-like or ba l l - l ike aggregates composed of p late- l ike crystals
(100-150p ) ; by a t t r i t ion of these aggregates to particles of l-10u , a
faster reaction was obtained (92% conversion af ter two hours). More data
and detailed pictures wi l l be presented. I t seems that the rate determining
step in the reaction of phosphogypsum with potassium chloride is the dis-
solution of phosphogypsum, which is obviously slowed when the aggregates
are dense and ba l l - l ike in comparison with thin-plate aggregates with a
high surface to volume rat io .
189
WN7
PRODUCTION OF ZINC OXIDE FROM WASTES
N. BONAN AND L. KOGAN
IMI (TAMI) Institute for Research & Development L td . , Haifa, Israel .
A hydrometailurgical process for direct production of zinc oxide from metal
oxides wastes has been studied. Pure zinc oxide is the most important zinc
compound, principally used as an activator in vulcanizing rubber. At present,
electrolytic zinc is industrially produced from wastes by the sulfate pro-
cess, based on leaching with suIfuric acid, during which most of the other
metal oxides present are also dissolved. A quite complicated purification
process of the leach liquor is needed before electrolysis/ and the product is
metallic zinc. The studied process is based on the zinc's amphoteric nature.
The leaching is performed by concentrated sodium hydroxide solutions (400-
600 g/1) a t 80°C. The alkaline leach is highly specific for zinc over such
other metals as iron or copper, only lead being dissolved at a low extent.
Thus the leach liquor obtained from a zinc flue dust sample containing 47%
Zn and 18% Pb, contains 7.2% Zn and 0.3% Pb. fA simple purification of the
leach liquor can be accomplished by cementation with zinc dust, based on the
higher electronegativity of zinc over many other metals such as Pb and Cd.
Pure zinc hydroxide is precipitated by 2-3 fold dilution of the leach liquor,
followed by f i l t r a t i o n and thermal decomposition to zinc oxide. Due to the
high specificity for zinc, low grade, cheap wastes, containing high amounts
of iron, copper, lead or chlorine, can be used. Sodium hydroxide is in
closed cycle, since i t can be reconcentrated and reused in the leaching
stage; about 25 t H9O/t ZnO have to be evaporated. I t is concluded that the\\
studied process is advantageous for production of pure zinc oxide from low
grade wastes.
190
WN8
STUDIES OF PHOSPHATE ROCK DISSOLUTION
WITH HYDROCHLORIC ACID
S. GARNETT AND S. UKELES
IHI (TAMI) Inst i tute for Research and Development Ltd. , Haifa, Israel
The rock dissolution step of the IMI Phosphoric Acid Process, developed in
the 1950's for the production of a high grade phosphoric acid has been re-
examined as part of a broader reconsideration of the process. The dissolution
step can be represented as the decomposition of f1uoroapatite :
Ca lo(PO4)gF2 + 20HC1 - 10CaCl2 + 6H3P04 + 2HF
The objective of the new study was to define the maximum calcium chloride and
phosphorous pentoxide concentrations which can exist in a stable solution at
40°C. A series of batch experiments were carried out at various acid/rock
rat ios, HC1 concentrations, temperatures and reaction times using Israeli
phosphate rocks. I t was found that for a P20g - rich rock (33% P 20 5 ) , stable
Ca+2 and P20g levels of 130-134 g/1 are achievable. The higher the "free"
hydrochloric acid concentration in the dissolution liquor, the more concen-
trated is the stable dissolution liquor that is obtained. The phase diagram
(Gmelins) for the system Ca+2-H+-P04"3-CT-H20 was used to calculate the
maximum theoretical P205 concentration achievable as well as the highest con-
centration of feed HC1 that, can be used. The calculated values are very
consistent with the experimentally determined ones. When the maximum Ca and
PpO5 levels are exceeded, then a white solid whose composition approximates
that of the double salt Ca(H2P04)2-CaCl2-2H20 is formed, as expected from the
phase diagram. Batch kinetics of the dissolution reaction at 50°C and 30°C
were studied by analysis of dissolution liquors and residues. While the dis-
solution behaviour of the major components (calcium and phosphate) as a func-
tion of time was readily interpreted, i t was not possible to draw specific-2
conclusions regarding species such as F , SO- and SiO-. The relevant data
is presented. These studies have been continued and the results are being
applied to the further development of the processl Some of the implications
of the work wi l l be discussed.
191
r WN9
THE REACTION OF CONCENTRATED SULFURIC ACIDWITH CONCENTRATED MAGNESIUM CHLORIDE BRINE
S. GARNETTINI (TANI) Institute for Research and Development, Haifa, Israel.
+ 2+ 2The vapor-liquid equilibrium in the system H , Mg /SO^ , Cl was studied.The distillation of the HC1 drives the equilibrium to the right:
H ^ + MgCl2(aq) .» 2 HCH + HgS04»+H20+
The reaction can be regarded either as the principal step in the productionof epsom salts (MgSO 'HgO), as the f i rst stage in a multistage process toproduce potassium sulfate, or as a means of producing concentrated hydro-chloric acid. In each case detailed information on the vapor-liquid equi-librium is required. From the study i t was found that the soluble magnesiumchloride increases the volatility of the hydrochloric acid and decreases thevolatility of the water. Thus, concentrated HC1, at or above the azeotropiccomposition (ca. 20% HC1), can be attained at nominal H+ and Cl" concentra-tions of 10% or less. In this system i t is clearly seen that the sulfate ionis a base. The HC1 volatility is proportioned to the product of nominalhyd»-ogen ion concentration (assuming that the HSO.~ ion is the only sulfurcontaining species) and chloride ion concentration. However, when the HC1liquid phase concentration doubles the HC1 vapor pressure increases ten-fold.Liquid-liquid extraction tests at room temperature suggest that the H+ acti-vity is much more strongly influenced by the presence of magnesium chloridethan is the chloride activity. A possible application of the information toprocesses to produce potassium sulfate will be discussed. This applicationrepresents an elegant use of the thermodynamic information present in phasediagrams to generate an industrially interesting process.
192
WN10
CHARACTERIZATION OF COAGULANT--HYDROSOL SYSTEMS WITHSTABILITY LIMIT DIAGRAMS
ALAN J. RUBINWater Resources Center, The Ohio State Unirersity,
1791 Nell Ave., Columbus, Ohio 43210, USA
The speciatlon of hydrolyzable metals such as aluminum(III) and the surface
properties of many hydrosols are pH dependent. It is not surprizing then, that
the stability of a sol in the presence of a given electrolyte may be strongly
controlled by the solution pH. Coagulation behavior and restabilization
phenomena in these systems can be followed by plotting sol turbid ley as a
function of metal concentration at constant pH or as a function of pH at a
fixed coagulant concentration. Such plots exhibit distinct regions of
stability and aggregation with sharp boundaries that are usually time inde-
pendent. Thus their extrapolation to the original turbidity of the suspension
yields crititcal values that are characteristic of the system. These
graphically determined critical values may be plotted log metal concentration
against pH to establish the stability limit diagram, or stability domain, for
the metal—hydrosol system. These diagrams are very useful for summarizing
large amounts of data and its various zones may be related to the mechanisms of
aggregation or stabilization. The construction of stability limit diagrams for
aluminum(III) salts are described in this paper. The sols that were examined
include a bacterium, titania, two clays, colloidal coal, mineral oil, sewage,
and starch. The approach was to obtain critical pH and concentration values
frcm changes in turbidity during settling of the sols. Each of the diagrams
will be interpreted and their common and unique features will be discussed.
A method, based on precipitate boundary analysis, will be described for relating
the slopes and intercepts of the boundaries to the hydrolytic chemistry of the
metal coagulant.
193
WN11
PREPARATION OF CORRELATION TO DESCRIBE A LIQUID-LIQUID EXTRACTION PROCESS
B. GRINBAUM *
* IMI - Institute for Research & Development, Haifa, Israel
To prepare a correlation which describes a chemical or physical process,
one requests :
1. A wide and reliable database.
2. Elementary understanding of the process.
3. A computer program for regression.
The database must fulfill 4 requirements : a. a homogenous distribution of theexperimental data over the sampling space, b. a sufficient number of data(significantly more than the number of estimated parameters), c. an estimate
of the experimental error in data, d. the sampling space must be larger than
the process range. The following problems were observed : 1. extremal change
in shape of the function over a narrow range of concentration, which caused the
correlation to deviate in this area. It was solved by increasing the density
of experimental data in that area. 2. Function fitting for curve of
complicated shape, was solved by splitting the curve to 2 areas, with different
fit for each. Having no idea about the exact extraction mechanism polynomials
were used, and gave good description of the system. 3. Coupling of variables
and estimation of the influence of various parameters in multivariable space.
This problem may be solved by making sets of experiments changing only one
parameter every time, and manual analysis of the behaviour using the existing
knowledge of the process.
The lecture demonstrates the mentioned above problems and their solution in
the process of extraction of
194
PHASE TR/.'.S.-LT c/-:,\: :<is in viz hsiERi
., WN12
OF PHENOLS 1:1 TH ALIM-IATIC
VAl Inst" ~'.! .5 -or lit-PO[! 313 ; :.i ";. ;If;"2,
Dsvul ori
In contrast to the mar.y papers on alkylation using PTC, the subject of phenol
ecylatior i;$ir,~ 6liph?h*c acid halides (in en aqueous-organic bi-phc$ic mixture)
appears to have been completely neglected. Fven reports on related work 3re fev:
and far tetv.een. Tluo the patent literature' ' reports ths synthesis of linsor
arornetic ?o".yc-iters via a. PTC reaction-between di phenols and orornatic diacid
'.r.i. r:::.+."i:ns r':!iynriciechlorides c-* p-er,ylphc?>phonic acid d-'!ial ide?.. A ;
forms tior. v!u s t tsck of csrboxylato cm ion on a:ii acid chlor ide , h?s t-:ei; cl ? 1:-; 1 -.1
by patent ' • . I l l e v ' has reported the reaction of acetyl chloride with various
phenols 1.si•"3 soVld y?.r',l rs the bars (in dicxpno \;ith tetrrbutylf^'icni-jni hydr:•'•..'•
sulfa te ?s ce t : - lys t ) . The PTC reaction betv.een dimethylphosphonechlorothicnr.la
and a phenol has also !-.f-en reported^ . We investigated the reaction of a
var ie ty c c Phenols with several a l ipha t ic acid chlorides in a mixture of chloro-
benzene and ac.iecus UsO'A solut ion. Tetrabutylammonium bromide (T?<AB) was the FT
ca ta lys t used. Unhindered phenols gave excel lent y ie lds of esterowith al l the
acid chlcrides examined with the exception of acetyl chloride which in sopie cisc-i
gave a lewer- (7O-3Q'.-) y i e l d . Hindered phenols gave high es te r yields only wit!,
those acid chlorides whose so lub i l i ty in water was suff ic ient ly low to enable
e s t e r i f ic:;t-lo:" t:. ccm^c-te e f f ic ien t ly 'with hydrolysis. T!:2 hichly hindered
phenol, 2 ,R-di- ter tbutylphenol , gsve negl igible yields of es te r with a l l the ?cicf
chlorides exesot octanoylchloride (ct..35", y i e l d ) .
\
1. Gevae»-t Phctotroducten N.V., Bnt., 891 781' (2/4/1957).
2. BASF A-*, iiL._P3L>A£Hl.» 29175 (27/5/1931).
3. V.O.Iili, Tetrahedron Letts. {26), 2431 (1979).
4. R.W. =i<ipw=y, U.S. Gree.-iside and H.H. Freecman, J. Am. Chem. S o c , 98 (7),
1979 [1976''.
19S
WN13
CORROSION CONTROL IN A HERRESHOFF CALCINER
M. SCHORR* , R. J. MUREINIK*** IMI (TAMI) Ins t i tu te for Research & Development Ltd. , Haifa, Israel
** Dead Sea Periclase Ltd. , Mishor Rotera, I srae l .
One of the stages in the production of synthet ic peric lase for refractorypurposes i s the calcination of magnesium hydroxide to magnesium oxide. To thisend, a multiple-hearth Herreshoff ki ln i s employed. I t consists of a cyl indri -cal s t ee l s h e l l , enclosing an arrangement of hearths b u i l t of refractoryalumina-si l ica bricks. Heating i s by combustion of natural gas. During calcina-tion a magnesium hydroxide slurry i s converted to dry magnesium oxide powder.Over a period of several years of operation of t h i s calcination unit , signs ofcorrosion of the ki ln shel l were observed. The she l l thickness was measured asa function of hearth number and the shel l temperature was mapped. Cores weredr i l l ed in each hearth and the corroded inner surface of the s tee l shel l wassampled. The thermal insulat ion - between the refractory construction and theshel l - was found to be wet and contaminated with chloride ion. The mode of thecorrosive attack and i t s main factors were diagnosed based on the temperatureprof i l e of the s h e l l , the chemical composition of the corrodents and the corro-sion products, and the ir crystal structure. Combustion products, oxygen andwater vapour reach the s t ee l she l l by diffusion through flaws in the refractoryconstruction and the thermal insulat ion layer. Dissolved 0 2 and C02, in aconductive, aerated s a l t and a lkal i so lu t ion , are responsible for the observedcorrosion. Since wetting by corrosive gases and vapours leads to corrosion,the kiln was insulated to raise the shel l temperature and prevent condensationof the corrosive agents , by the application of sheets of glass wool to the out-s ide . Corrosion was reduced s ign i f i cant ly and the ki ln i s operating s a t i s -fac tor i ly according to schedule.
196
WN14
SELECTION OF CORROSION RESISTANT MATERIALS FOR WASTEMATER COMCENTRffiPORS
M. SCHORR*, E. WEINTRAUB*, E. MILLER*** M I (TAttI) - Institute for Research and Development, Ltd., Haifa, Israel** IDE - Israel Desalination Engineering, Ltd., Herzlia, Israel
Israel Desalination Engineering, Ltd. has recently introduced an energy-efficient industrial concentrator for wastewtter treatment and disposal. This
concentrator produces two types of strews: A low volume concentrate stream that
can be reused or can be disposed cheaply and distilled water. Since wastewater
differs widely, corrosion-resistant materials of construction for each type of
wastewater should be selected. Corrosion in wastewater depends on the nature of
.Its contents, the dissolved oxygen level, the pH and the degree of agitation.
Apart from corrosion, deposition and crystalization of scales occurs in equip-
ment handling hot effluents, specially on metallic heat-transfer surfaces. The
aim of this work was to evaluate novel methods and techniques'of selecting prop-
er materials of construction for IDE concentrators. Three types of wastewater
from the inorganic chemical industry, having different levels of pH and salt
concentration were examined. The metals and alloys selected for testing:
Titanium, austenitic stainless steels and aluminum-magnesium alloys, are those
currently used in the chemical industry. The electrochemical and corrosion
behaviour of the metallic materials tested was determined by two methods:
gravimetric and electrochemical. Potentiodynamic and potentiostatic, anodic
and cathodic polarization plots Were obtained using an electronic potentiostat
and a three-electrode cell. The susceptibility to localized corrosion, e.q.
pitting and crevice was determined applying a cyclic potentiodynamic polarization
technique. It was found that titanium exhibits corrosion resistance to all types
of wastewater examined, the austenitic stainless steels are resistant to the
alkaline and acidic types, but suffer from pitting corrosion in concentrated
saline brine. The Al-Mg alloy corrodes in the acidic solution and shows pitting
in the alkaline wastewater. Results from the gravimetric and electrochemical
measurements are presented, the corrosion behaviour of the alloys is illustrated :
and the implications for industrial equipment are discussed. - •-?
197
WN15
FACTORS AFFECTING THE FILTERABILITY OF GYPSUM
OBTAINED IN A BENCH SCALE CONTINUOUS UNIT FOR MPA.
E. BEN-YOSEPH, C. HOLOENGRABER, J. METCALFE AND S. GRYC
IMI (TAMI) Institute for Research & Development, Haifa, Israel .
t
The f i1terabi1ity of phosphoric acid in the WPA process depends on the
size distribution of the gypsum. The size distribution is dependant on
the nucleation and growth rates. Variations in the size distribution
lead to variation in the f i l t e r a b i l i t y which is a decisive parameter in
the WPA industry. A basic study on a bench scale continuous unit was
in i t ia ted . Several Israel i phosphate rocks with different compositions
were tested in a bench scale continuous unit for WPA. The effect of
parameters on the f i l t e r a b i l i t y properties was examined.
198
^ -^- \
WN16
SOLUTE RELEASE IN MULTIPLE EMULSIONS
S. MAGDASSI, N. GARTIThe Casali Institute of Applied Chemistry, School of AppliedScience and Technology, The Hebrew University, Jerusalem 91904,Israel t ^
Multiple emulsions of the w/o/w type are oil in water emulsions
in which the dispersed oil drops contain smaller dispersed water
droplets. There are many potential practical applications of
multiple emulsions but no commercial product is known, mainly
because of the instability of those emulsions. The most common
release pattern of solutes from the inner aqueous phase is through
the breakdown of the multiple droplets. We have achieved a
physically stable multiple emulsion, but the release of solute was
not prevented, probably due to diffusion of the solutes. It was
found that the release rate is dependent on the electrolyte type,
and that even when 100% of the solute was released, the emulsion
was still of a multiple nature. The dependence on the electro-
lyte type was also observed when two electrolytes existed in the
inner aqueous phase. Further support to the diffusion mechanism
is the release of electrolytes at different initial
concentrations, which was the opposite to the expected release if
it was caused only by the breakdown of the multiple droplets. As
a result of this study, it was concluded that physical stability
of multiple emulsions is not sufficient for obtaining stable
formulations of multiple emulsions.
199
KM"
PHASE TRANSFORMATION OF COCOA BUTTER AND BLOOMING IN CHOCOLATE
J. SCHLICHTER, S. SARIG, N. GARTI =The Casali Institute,^ School of Applied Science and Technology,The Hebrew University of Jerusalem, Jerusalem 91904, Israel
onocolate blooming is caused by separation of cocoa butter, the
main constituent, from the brown non-fat phase. This phenomenon,
occurring more frequently in summer, is deleterious for chocolate
quality. Owing to the strong polymorphism of cocoa butter,
blooming seems to be due to the transformation of V forrr, to VI
form during storage. The study was divided into two parts:
J. 'ihe study of polymorphic behaviour in cocoa butter) 2. Under-
standing the causes of blooming. In the first part, the trans-
formation conditions from V form to VIvswere clarified. In order
to accelerate the transformation, which takes two months at room
temperature, a method of temperature cycling between 2C/CC and
30 C was used. It was found that this particular transformation
could not occur through liquid phase, like lower transformations,
rut only through solid phase, more exactly, through'soft phase.
It was found that after crystallization solid emulsifiers,
increasing the amount of the liquid fraction, retard the trans-
ioriuation of V form to VI form, and accelerate the transformation
of IV form to V forrr.. It was also found that combination of
Gpa:i''oO and Tween 60 is especially efficient in the V form
retention. The three main steps of chocolate manufacture,
namely tempering, cooling and^jstorage, if prdperly performed,
ensure gloss and prevent blooming. In chocolate, emulsifiers
were found to act both as surfactants and crystal modifiers.
'Ihey can nelp to correct faults in some steps of manufacture.
200
-,, r
WN18
STRESS MBUSURBIBiTS IN MgF THIN FILMS BY MODULATE)
TRANSMISSION SLLIBSOMS'RY (MTE)
A.LUBESKY -**
I.LUBEZKY - D.S.JACOBS.***
* - Univ. of Haifa School of Mucation of the Kibbutz Movement.ORANIM«** - Ministry of Defence, P.O.B. 2250, Haifa.M # _ Lai. of Laser Btergetics, Univ. of Rochester, Rochester, N.Y.
Many publications describe or suggest a correlation between thin films stress
and their mechanical properties including laser damage resitance.Modulated
transmission ellipsometrg (MTE} can provide information on stress in dielectric
thin film-substrate systems with spatial resolution of the order of 10-20 u.m.
In the present work the sensitivity of the MTE system was demonstrated through
the measurements of the residual stress in BK7 glass and fused silica before and
after sequences of annealing procedures to several different temperatures.The
stress in MgF /BK7 glass and MgF /fused silica systems was also investigated.In
each case the stress profile of the substrate prior and after deposition was
measured.In all of the measurements a significant lowering of the stress in the
coated area was found as compared to the substrate prior depositionjthis indic-
ating that the stress in the MgF film partially cancels the substrate stress.
The values of the stress could be calculated from the measured optical phase
retardation f given hyt4* t**n were t is the component thickness and *n is the
change in the refractive index or birefringence resulting from internal stress.
The optical phase retardation is directly proportional to the stress-CT-within
the sample.The stress values found for MgF on fused silica and MgF, on BK7 glass2 2 '
were 3900 kg/on and 2300 kg/cm respectively.The stress of the MgF thin film
on the two different substrates was measured as a function of time.A cowering of
the stress by 10-30% was found.Two factors may contribute to this effectil.a
relaxtion prpness in the MgF film/substrate system and 2. the adsorption of0
atmospheric water by the MgF film.On baking the MgF film/substrate to 400 c
an increase in the stress by 30-50% was observed.This may be connected to desorp-
tion of the water and sintering of the MgS^ surface.We also found indications
that the stress increased as the evaporation rate was increased.The total stress
that was measuredffor th^sj*ftlm was further divided into two components the int-
rinsic s and the thermal S stress.By a simple and straight forward caculationthe contribution of each component to the total stress was evaluated.For the MgFfused silica S -700 kg/cm*"and S *3200 k?r/cmhtnd for the MgF /Bk7 glass systemthe contributions were 700 kg/cm^and 2300 kg/cm^respectively.
201
WN19
SORPTION OF BROMINE ON ACRYLIC FIBERS
H. GUTTMANN, M. LEWIN, I. NAORIsrael fiber institute & School for Applied Science and Technology,
Hebrew University, Jerusalem
The interaction between aqueous bromine solutions and acrylic fibers was
investigated. From the data, kinetic and thermodynamic parameters of sorp-
tion were calculated. The diffusion coefficient was found to be 3.3 x 102 -1
cr. -sec . Bromine sorption is accompanied by swelling and loss in strength
of the fiber and thc-je effects increase with increasing bromine concentration.
The Tg of the polymer is lowered and thus bromine acts as a plasticizer. bro-
mine can be washed out of the fiber witti aqueous ammonia solution. The
anmonia penetrates into the polymer, reacts with the bromine, producing NH,3r
and N,, and this process causes changes in fine structure of the fiber. This
is accompanied by a rise in strength with' respect to that of fiber treated
only with bromine. Pores are formed vithin the fiber, thus raising its ab-
sorption capacity. In this way it is possible to raise absorption of dis-
perse dyestuffs by 40°= and of basic dyestuffs bv 25%.
202
WN20
CRYSTALLIZATION OF MICKOCRTSTALLIHE CELLULOSE
M. LEWIN, H. GUTTMANN, D. SHABTAI
Israel Tiber Institute & School for Applied Science and Technology, HebrewUniversity, Jerusalem
o •.< '-
Microcrystalline cellulose is produced by an exhaustive hydrolysis of puri-
fied native cellulose, followed by breaking up the crystalline aggregates
by shearing action. The degree of polymerization of microcrystalline
cellulose used in this study corresponded to a fluidity of 18 rhes (recipro-
cal poises) and its x-ray crystallinity index was 0.5A. The accessibility >
by the bromine method and by the I.R. ratio —5^-= - was 0.44 and theoSJ cmwater regain 7.41 X. Treating the microcrystalline cellulose with a 1.81
moles/1 Br0 solution brought about a pronounced increase in the crystal-
Unity of the material, which was basically similar to previous results on
cotton and other celluloses. Upon treatment for 23 hours at 40°C, the x-ray0
crystallinity index increased to 0.67 and the I.R. accessibility decreased
to 4%, along with a decrease in moisture regain to 64%. The fluidity in-
creased only slightly to 18.3 rhes. A drastic change in the not alkali solu-
bility and in the yellowing of the alkaline extract was also obtained. The
above results indicate that the microcrystalline cellulose became almost
entirely crystalline due to the aligning action of the charge transfer com-
plex bridge formed by the bromine molecules between neighboring chains. The
hydrolysis brings about the cleavage of the polymeric chains in the LORij °
between the crystalline regions and thus increases the mobility of the chain
ends. While this increased mobility assists the crystallization to a small
extent (up to crystallinity indeces of 0.54) a chain orienting factor is
needed to produce high crystallinity.
203
WN21
ONE ASPECT OF GYPSUM DEPOSITION IN DEAD SEA MATERAND ITS MIXTURES WITH MEDITERRANEAN SEA WATER
B.S. KRUMGALZIsrael Oceanographic & Limnological Research, Haifa, Israel
If the widely-discussed project, the Mediterranean - Dead Sea canal, will befulfilled, these two different water bodies will be mixed. When this mixingtakes place, two opposite effects will occur: the SO?" anion concentration willincrease but the Ca cation concentration will decrease in the mixtures ofthese waters. Complex behavior has been found regarding the degree of gypsumsaturation for Dead Sea and Mediterranean Sea water mixtures (Katz et ai.,1981; Levy, 1981; Krumgalz and Millero, 1982, 1983). It was found that thegypsum formation process in the Dead Sea under present conditions is limitedt\y some kinetic factors. The question now is, if gypsum crystals will beformed owing to the mixing of Mediterranean and Dead Sea waters, how long willit take these crystals to sink to the sea bottom? The rate of gypsum crystals'deposition was calculated by
d g (ps - p)
4
*1 18 nwhere \|J. is the configurational coefficient characterizing the directions ofprecipitation and the gypsum crystal axes. Using our measurements of the den-sity and viscosity of Dead Sea water and its mixtures with Mediterranean Seawater, the deposition rate of gypsum crystals with equivalent diameters of 12,
it15, 20 and 25 u at different temperatures was calculated. These calculationswere carried out only for those mixtures which, according to thermodynamiccalculations (Krumgalz and Millero, 1983), are ovefsaturated with respect togypsum. The analysis of the results obtained shows that the deposition ofgypsum crystals with equivalent diameters more than 12 u in the water columnof Dead Sea water and its mixtures with Mediterranean Sea water will be rela-tively very fast. Therefore, according to these data, there is no danger thatthe gypsum which can be formed under certain conditions will float on thewater surface.
204
TO1
NONMMERICAL COMPUTER APPLICATIONS IN CHEMISTRY - A GRADUATE UNIVERSITY COURSE
Y. NOLHAN, Departaent of Organic Cheaistry, The Hebrew University, Jerusalea,
Israel
Cheaistry graduate students are coaputer literate, however only few of
thea are aware of soae of the nonnuaerical coaputer applications in chemistry.
In order to aake our students aware of the various nonnumerical coaputer
applications we have developed a two credit points graduate course entitled
"CHEMICAL INFORMATION SYSTEMS". This course covers the structure, use and
application of chemical information systems in scientific research. Topics
cjbvered in this course are coaputers hardware and software, computer communica-
tion systems, computer representation of chemical structures (e.g. WLN,
connection tables), bibliographic database, structural and substructural
search (CA bibliographic files, CAS ONLINE, DARC, SANSS), numeric databases,
pattern recognition and its application in chemistry, computer assisted
structure elucidation, computer assisted chemical synthesis, artificial
intelligence, an outlook to the future... The lecture is followed by
demonstration using various available data bases, computer simulation
programs and computer programs. Grades are given on the, basis of a written
assigned paper which is turned in at the end of the course.
205
W02
COMPUTERS IN THE LABORATORY: A .HOVEL
METHOD FOR TEACHING ON-LINE COMPUTING
M.BtN-ZION 'Dept. of Chemistry, Bar-IIan University, Ramat-Gan 52100, Israel
A novel approach to teaching on-line computing to chemistry and biology students
is the basis for a course entitled COMPUTERS IN THE LABORATORY. Originally
designed for third year chemistry undergraduates, the material and methods have
also oeen used with similar success in 3ar-Ilan's high school computer workshops.
The Dasic philosophy of the 60 hour course is to provide the students with the
necessary skills to exploit the resources of the department's PDP 11/40 mini-
computer during their graduate careers and in their future roles as scientists.
The formal lecture material includes BASIC programming and graphics, hardware
design for instrumental interfacing, software considerations with regard to
datd acquisition and processing and techniques for real-time interaction.
A considerable amount of software was developed for the course in the DASIC
language and is implemented in teaching, the BASIC language itself, in utilizing
the VT-11 graphics display, ana in providing access to the entire range of
sampling techniques permitted by the laboratory interface units.
lite programming assignments are designed to emphasize, the poignant portions of
the subject matter while at the same time holding the students' interest.
Perhaps the most unusual aspect of the course is the fact that the students sit
in front of and use tne computer terminals during the actual lecture sessions.
The locture is accompanied D> overhead projections of programming examples for
cne siudent to execute during the session.
This inethoa of "teaching at the terminals" proves to be agonizingly slow during
tne first few lessons while the students are busy familiarizing themselves with
tne operation of tne terminal ana tne uASIC operating commands. By the third or
fou^tn session, the lecture pace reaches an optimum level, and by the time the
first programming exercises art distributed, most of the practical and technical
difficulties usually encountered by new programmers are conspicuously absent.
; n
THE USE OF MICROCOMPUTERS FOR THE SOLUTION OF PROBLEMS IN CHEMISTRYa ^
Y* MARCUS, A. LOEMENSCHUSS
Dept. of Inorganic and Analytical Chenistry, The Hebrew University,Jerusalem
Microcomputers are becoming wore COMMOD, and arm used also as hone
or personal computers, but we found that advanced undergraduate
and even graduate students were reluctant to employ then < Possible
reasons are the necessity to learn a conputer language and opera-
tional rules and an insufficient ability to translate problens into
computer logic* We therefore teach the studentsMthe required skills
and enphasizes the easy access to Microcomputers and their applica-
bility to problens in chemistry* The language to be used is BASIC,
which is easy to learn and flexible in its application. The purpose
of the course is neither to turn the students into conputer experts
nor is it ained at those who use conputers as their nain research
tool* We hope to inpart notivated student a feeling for what the
nicroconputer can do for then*
The course consists of a few introductory lectures* followed by
guided hands-on work in an informal setting* Lectures include*
the nicroconputer and its structural logic ; storage and retrieval
of infornationf peripherals, elementary progranning in 'basic';
formulation of problens as flow-schenes and programs; advanced pro-
granning 'files and strings; conputer graphics* Practical examples*
linear regression by least squares} consecutive or sinultaneous
exponential decay curves; numerical integration; roots of equations
by the Newton-Raphson method ; deconvolution of spectral or chroma-
tographic peaks; determination of eigenvalues; titration- or pola-
rographic curves, activity coefficients of weak electrolytes; force
constants from vibrational spectre; simulation of spectra; etc*
Concerning the inclusion of on-line uses* we note that computerized
data collection and evaluation is increasingly applied, but the in-
corporation of specific computers in instrumentation nay make this
less relevant*
207
W04
A COMPUTER-ASSISTED INORGANIC CHEMISTRY LABORATORY EXPERIMENT?THE DETERMINATION OF COMPLEX FORMATION CONSTANTS
Y. MARCUS, S« GLIKBERG
Dept» of Inorganic and Analytical Chemistry, The Hebrew University,Jerusalem
The purpose of this experiment is to train students in the conver-
sion of 3 set of experimental data that they obtain themselves into
s set of complex for nation equilibrium constants with an objective
evaluation of their accuracy* The Mathematical and statistical
requirements from the students are kept tci & frtoimuM fry choosing a
system where the oquations are .Linear iri the»e V-on;vt.ant&«
The distribution equilibrium of Nercurydl) bromide ftftw eii toluene
i-srid en S Q U B O U S solution containing excess broru.de ions is such a
«r-ysteri> The distribution ratios in 11 sample::; of '.'si IOI.'S. L £: r • ~"."' are
;:>f»tained at equi t ibr :i um iron clupj xbWte spe(M-ropho-i,oM{-.'tr :i ~ ••jetermi. ••••
notions t>y the riithizone mei-hod • ' She. working ©qur-tion :i. =•
where 11' is the dastrxbutiori rat io and I , K ninci K ere the
uM constants. The student;:.- sve required fit-F-t. to t reat the
•Jots graphical ly, and dtaw conclusions cancernine their va l i d i t y
and approximate values of the constants* Then they feed the data
ivito :; mult iple l inear regres^jon program. They are tsuejht the mea-
r'tnciii oi conrpptt; sorh as vc>! i«nccj) K-t^-u. arid Muiltiplc? regression
'.• • <:. < *• i :' i c :i e n t .. a n d f :i. r i ?.> 1.1 ^ c: • o m p a r e ! • n <.-.' a T c n t •> s t ?.! i •; t ~. w i t h r e p o r t e d
• ' b . ! . . i t - - . , . T h e ^ : a r t 1 t f n ' r - p r t ? " : - c n t e o w i t h + - h « w h o l e - p r o c e s s c - f c i s t a
?t OI.I , «j r. j. or, nr oce;i= :i i..: -Ttn <i.i,a1..i..jiLiiili-j] e v a l u a t i o n , the l a t t e r two
i.f-H-1* f>-:. Means of a cc'>Mf>''t»i •
206
W05
THE MICROCOMPUTERS AND CHEMICAL EDUCATION
Z. SCHERZ, R. BEN-ZVIDept. of Science Teaching, The Weizmann Institute of Science, Rehovot,
4 Israel.
The microcomputer is Increasingly becoming a common feature in many chemistryclassrooms and laboratories. Computer Aided Instruction (CAI) programs whichare Instructional /software (courseware) that provide learning through Inter-action with the computer,were recently developed in U.S.A. and Western Europe.There are five levels of CAI that can be employed using the microcomputer:1. Dri l l and Practice, which provides an opportunity for individual practiceof classroom material. 2. Tutorial, which is an Instructional entity in thecurriculum that teaches rules, concepts and contents within the subject matter.3. Gaming, a situation where students have to manipulate facts and skills inorder to win the game. 4. Simulation, a situation where physical reality ortheoretical models are simulated via the computer. 5. Problem solving, astimulus situation which combines previously learned rules into a new higherorder rule. Other uses of microcomputer such as data processing and analysing,class management and interfacing to laboratory equipment can also beimplemented in the chemistry class. Only few of the chemistry software packagesthat are available in the market can be considered to have good instructionaland educational value. In the Weizmann Institute of Science we are startingto establish a microcomputer oriented team by collecting and reviewing existingcoursewares and developing original high school chemistry CAI. One specificaim is to use the computer's special features to enable better instruction ofsome chemistry topics e.g. models, kinetics, chemical bond. A second aim isto develop programs aimed to treat students' misconceptions with regards tochemistry concepts.
209
W06
OUT OtGANIC AND INORGANIC CHEMISTRY BE INTEGRATED IN
A TERTIARY LEVEL COURSE ?
MAVA BEN-ZVT, EVERYMAN'S UNIVERSITY,
TEL-AVIV, ISRAEL
The limits of the various branches of Chemistry - organic, inorganic
and physical chemistry - are quite difficult to define in recent years.
This fact brought up the idea to develop a multimedia course in the
tertiary level encompassing organic and inorganic topics.
A textbook suitable for both introductory organic and inorganic chemistry
cannot and should not be encyclopedic. Therefore every effort has been
made to present the many facets of chemistry rather than to treat
exhaustively selected topics.
The emphasis in this course is on structural and bonding principles,
mostly based on W, VIS, IR, NMR and MS data. Still it is believed
that sufficient^ "descriptive" chemistry has been included to give the
student a good appreciation of the range of properties and reactions
encountered.
Students studying this course are of Everyman's University student
population, coming from exceedingly diverse backgrounds and of differentmain interest of study. The matin ideas and the use of variety of
audiovisual aids a.ir? laboratory techniques which serve in the course
are presented in the poster.
210
W07
THREE-DIMENSIONAL POINTERS FOR STEREOSCOPIC PROJECTION
H.J.G. HAYMAN
Dept. of Physical Chemistry, The Hebrew University of Jerusalem, Jerusalem,Israel .
Stereoscopic projection involving separate pictures for each eye is often used
for i l lust rat ing molecular structure but suffers from the disadvantage that an
ordinary pointer cannot be used for indicating a particular atom since each
observer would see such a pointer in a different position with respect to the
stereoscopic image. This d i f f icu l ty can be overcome by using stereoscopic pro-
jection not only for the molecule but also for the pointer i t se l f . Two separate
images of the pointer are projected onto the screen via polaroid f i l t e r s so
that an observer using appropriate polarizing glasses w i l l see a single pointer
in space at a distance in front of (or behind) the screen depending on the dis-
tance between the two pointer images on the screen. Three different pointers
based on this principle have been used; the f i r s t of these uses two V-filament
lamps mounted side by side and projected onto the screen by means of two achro-
matic lenses. Changing the distance between these two lenses changes the dis-
tance between the two V-filament images on the screen so that the single stereo-
scopic V-filament image noves towards or away from the screen. This pointer
can also be used satisfactori ly with anaglyphic projection by replacing the two
Polaroid f i l t e r s by red and blue-green f i l t e r s , respectively. The second of our
three-dimensional pointers was designed for use with a double-headed overhead
projector. Two parallel wire pointers immediately below the glass stage sup-
porting the stereo-pair transparency are projected together with the transpar-
ency; changing the distance between these two wire pointers causes their stereo-
scopic image to move towards or away from the screen. Our third three-dimension-
al pointer was designed for pin-pointing the individual atoms of complex mole-
cules such as proteins. A beam-splitter is used to obtain two parallel beans
from a He-Ne laser and these beams after passing through low-power lenses and
Polaroid f i l t e r s form two red spots on the screen. The distance between these
two red spots- and hence the distance of their stereoscopic image from the screen
is changed by lateral movement of the above-mentioned lenses.
211
wos
CHEMISTRY COURSE AS A MANS OF INTERGRATING STUDENTS OF DISADVANTAGED
BACKGROUNDS INTO ACADEMIC STUDIES
S . YARIV*AND R. COHEN**
*Dept. of Inorganic and Analytical Chemistry Hebrew University Jerusalem Israel
**Pre Academic Centre Hebrew University Jerusalem Israel
At the Pie-Academic Centre of the Hebrew University students of disadvant-
aged backgrounds are being prepared - through the study of various disciplines -
for the required standard for university admittance. A successful completion
of the course enables the students to intergrate and compete with other student?
at the Academic level. Chemistry is among the :ourses given in this framework.
The standard of the students and limitations of time dictate the curriculum in
chemistry.Molecular and crystal models are used extensively to concretise the
concepts involved at the microscopic level. Kiotivation and interest are raised
by classroom demonstrations of phenomena and reactions. Qualitative- and
quantitative exper ments are performed by the students themselves during
laboratory periods. Films serve to enrich and to clarify selected topics.
With regard to the specific difficulties of the student population emphasis has
been laid on the acquisition of learning habits catering as much as possible to
the individual needs of the students. Learning, recalling and organizing
facts serve as a first ste^ to arriving at conclustions. Clear and precise
expression of written u.siteri:.l in essays, laboratory reports, special projects
and examinations, while a3so usii-g mathematical skills, is a crucial part of the
scientific education. Although the chemical sylabus foilowed is comparable to
that of the four credit high school chemistry sylabus, still the methods and
emphasis of the course at the l're-Academic Centre are definitely unique.
The organization of the course and related materials are presented in the
poster.
"M"
W09
THE CHEMICAL CARD OF THE ELEMENT
S. AL1 - P . O . B . 9596 HAIFA 31095"Motanaby" School - Motanaby st. 10, Haifa.Dept. of Chemistry, Bar llan, University, Ramat Gan, Israel.
The Idea: The Chemical Card of the Element is one answer how tostudy the descripitive chemistry. We suggest a cueniical card forevery element like the identity card that the state give to thecitizen. The chemical card of the element is a chemical activity forthe pupils of the secondary school.The structure:
1. Part one include the Title and the private picture of the element.2. Part two include the general properties of the element that
exist in the periodic table of the elements.3. Part three include some papers that talk about the chemical
and physical behaviour of the element, abouti its uses
and about its discovering.There are some additional papers like the paper of generalconcepts and the paper of the periodic law.The Aimes:1. to go more deeply in the chemical element.2. to encyclobyde the chemical elements.3. to study the principles of chemical reserch.4.,, to build a working, reserching pupil and to develop the
love of chemistry.
213
o woio
CHEMISTRY MANAGEMENT - A NEW ORIENTATION FOR A BASIC SCIENCE
o u
IRVIN M. GOTTUEBCollege of Arts and Sciences, Hidener University, Chester, PA, USA
THE CHEMISTRY MANAGEMENT PROGRAM is designed for the student who is interestedin chemistry but does not wish to follow along traditional research-laboratorycareer lines. It combines a broad background in the discipline of chemistrywith a comprehension of the principles of business (accounting, economics andmanagement) so that the graduate can recognize what information is pertinentto a product or process and evaluate its industrial significance. He is pre-pared for an administrative position in a chemical organization, medical fa-cility, product marketing, operations management, or as a financial investmentand portfolio manager in the chemical industry.
214
AUTHOR INDEX
Ackeraan B.Adan N.Addadi L.Agaon N.igranat I.Aizenbud M.
rtli S.Altaian J .fcairav A.Anner 0.Apeloii; Y.Apfelbauo-Tibjka F.Araks*a A.Ardoo MAserin /•.Atl.is DA u s t i n E .R.A*'!• ' .* D .
A / r j y <•'.
Avrapoff M.
•
Bast-.n Y.Ba!uf l A.B-vi b o y JN- .
Partsch ;<..•"•L-rt VZi i .3 - - ,'i' lfO'ti 5 .Becker J . i \IVlfer S.Hen-Ashtr J .Ben-Dor L.Hen-Nairn A.Benny D.Ben-Yoseph E.Ben-Zion !!. /bin Zvi N. /.'en-Zv. R.berger S.Krkovjtch-Yellin Z
AbstractNuaber
WK5TG7
W3.WK9WI3WK4KN6
W09TD12
TA6TC7WL1
TFl 4WJ7
TFl 3TG5WK4TGiTC3WM1IDS
WK6TD18
TC2TF.i 8
WJSWHfJWN1WN2
TF1/JT2WJ11TD25Vu\i5
W02W06
wosWK11
TD17
AbstractPage
16312841,167
144162189
213845468
173l i b
15213512616212264
18280
L643063
1201SJ1411HA185103,J04156
9719820621020316941S3
Bhattacharya RBiali S.E.Bino A.Birnbaum G.I.Blutstein Z.Blum Y.Boiduan F.Bonan M.Bony ri.Bradford T.J.
^Brandeis M.Bravernan S.Brenner I.B.Buch V.Bulkm B.J.Buncel E.
Cahen I1.Ch^rit \.Chen Y.-W.D."hocron S.C'orev M.Cohen A.Cohen H.
Cohen *-;.Cohen R.
Cchfiii Y.Cohei. Z.Crammer B.C/gler M.O . - i p s k L • G.
D a n i->.
Dar.ir. A.D-iviio. ' DDeg?.t;i V.Deutsch 0,Devoi K.A.
Abstract AbstractNumber Page
.N. WH6138WL4 176
TF5.TF14 107,116TE2 103
WN4,WN5 187,138TD2? 99
TA4 52V/M7 1 9 0
TCS atTGi 1 2 -TC4 t>5
TD13 «:•TG8 12?WI4 1 15TAl 49Vc2 101
WHS. WH6, WH"' 137 , .1 38 ,139KM2IB3\k[<7 1 J £ :
TD;: 74W K 3 , W K 5 . W K : C i«5i . i £ 5 , i » S
TGS 124T F 8 , T F 9 , i T 1 0 J 1 0 , 1 T . , 3 1 2T F 1 1 , 7 F 1 2 3 1 3 , 5 14
WJl 14' i'«DS 2 - 2 1
1VL7 i ' / C
•1,3 7 5
TE2 131 |WJ10 155
TFl 10CWK8 16f>TF3 iObTf? 70
WK14 i 7 2
tII
AUTHOR INDEX, ( c o n t ' d )
Diuant S.Dinnocenzo J.P.Direktor D.Doab A.Dori Z.Duddek H.Duval V.
bden L.Effenberger R.Eisenberg H.Egozy Y.Elber R.Lister H.Engelhard T.Luge1 man R.Lren l>.kwenson A.
Farkash-Solomon Tharver 0.leathers tone J.I).leitelson J.Icldman 1).loner 11. A.frank V.1- round M.1riodman N.1 rin. R.i rimer A..\. T1U0l-rolow 1 .
liariiftt S.(.art: \ T!:b
W.MGedai la . .Gefen S.Gerbrr k.B.
AbstractNinber
WK4TE3
WN12WM1T2WK8TB4
WK8WN12W2
W.\'lTB1.TB3
WH2WH6TA"TD21WK10
WL5WJ12
F.. TT7TC2
TD26TG6.TG7
KJI:Tin 5
WL8,TD11,WL5
Kl.5
WN8,K'M>.TG5.NX16-
WJbTB1.WI4
AbstractPage
1621021951823216660
166
195401845713415S5593168
1751571096398
12",15"85!M1808J,1"
i y i ,108,2001091515",
59
12S
S3,
o
\92120.
145
Gibson D.Gileadi E.Glinski-SharonGilon C.Gilon N.Glikberg S.Goelaan G.Goldberg I.Goldblum A.Goldfarb D.Goldschmidt 2.Goldstein M.J.Goldstein S.Goldzweig I.Golub 1).Gonen 0.Goren Z.Gottesfeld S.Gottlieb H.E.Gottlieb I.M.Grauer Z.Greenshpoon N.Grinbaum B.Gross Z.oGrushka E.Gryc S.Gun J.Gut nan A. 1..Guttcl C.Guttmann H.
l"5Haas V.Ha low A.
, Halic: L.Halpern M.Hameiri .1.
199llarel G.Ilase G.-Hassncr A.Ha\Tnan H.J.G.
AbstractNumber
TF5WS.WH4
P. TD10TD18.WK3.WK10
WK5WJ3.W04
WI1TD13WK4TA3TD5-TE3WJ10WK7TF10TCITC10TF15,,TA2
W0101C5
TD20WK11WL2
TG5.TG4KM 5TB5KK2TG4
KN19,W;\20
TC6.TC7TD5TG8
TD26TO 11TV 19WJ7T5WO'
Heitner-Kirguin C. TF1"
AbstractPage
107 ;46,136
8290,161,168
163148,2081428516251751021551651126271117502146492194174124,12519861160125 A202,205
67, 68— -
12998 '8312115255211119
AUTHOR INDEX (cont'd)
Heo G.S.Herbstein P.FHerzig J.Hirsch D.Hodes G.Hoffer D.HoldengraberHolloway J.H.Hoz S.
Ikan R.Joselis P.Ishiwatari R.
Jacobs D.S.Jacobson K.A.Jodl H.J.Jortner J.
Kais S.Kaiser M.Kapon M.Kassovicz J.Katriel J.Kedea 0.Keinan E.Kertes A.S.Keua S.R.Kirowa-EisnerKjaer D.Klein J.Kogan L.Kolodny N.Korngold E.Kosower E.M.Kreaer M.L.Kruagalz B.S.
AbstractNuaber
TF181. TD16
TD19TF6WH6TG8
C. WN15TF4WL2
TD3,TD4,TD5TD4TD4
WN18TD7TA4TA6
WJ1WK8TD16TG2WI2TF16
TD19,TD20,TD21NJ2TE2
E. WH4WK12Wl
WN6,WN7WK12WN1WK1WJ9NN21
AbstractPage
1208891108138129198106174
75, 76,777676
201795254
1461668812314311891, 92,9314710113617039189,190170184159154204
Labes M.M.Lahav H.Laufer R.Leiserowitz L.Levanon H.Lewin M.Libaan J.Licht A.Lifshitz A.Lifshitz C.Light J.C.Lipscoab W.N.Loewenschuss ALubezky A.Lubezky I.Lupin M.S.Luski S.Luz Z.
Magdassi S.Magyar B.Maidan R.Malinovich Y.Mandler D.Narcu V.Marcus Y.Margulies L.Mayer I.Mazur Y.Mechoulan R.Meiri N.Metcalfe J.Meyerstein D.
Michaan M.Miller E.Minsky A.Mohtacheai R.Morinaga S.Moiseyev N.Mureinik R.J.Muszkat K.A.
Abstract AbstractNuaber Page
TA3 51W3 41
WK10 168W3.TD17 41, 89
TCI 62WN19.WN20 202,203
WK13 171WJ12 157WJ8 153
W5.WJ6.WJ7 43,151,152TB2 58TF18 120
TA4.WO3 52,207WN18 201WN18 201TGI 122TF5 107
TA2,TA3 SO, 51
WN16 199TF13 115TC10 71WJ7 152TC9 70WH8 140
WJ3,WO3,WO4 148,207,208WJ13 158TF7 109
WL5.WL6 177,178TD14 86WN3 186WN15 198
TF8,TF9,TF10 110,111,112TF11.TF12 113,114
TD2 74WN14 197
WL7,WL8,WL9 179,180,181TD2 74TD4 76TA5 53WN13 196WJ4 149
217
AUTHOR INDEX ( c o n t ' d )
Naaaan R.Nagler R.Nahor G.S.Naor I.Nissani E.Noiik A.J.Nudelaan A.Nugiel D.A.Nutkovich M.
Olsher U.
Paldus J,Parkinson B.Parola A.Parson K.W.Patchornik A.Pauncz R.Pecht I.Peled E.Perahia D.
AbstractNuaber
TC5TF7
TC11WN19WJ5WHS
TD19.WK11WL4TF8
TF18
WI2WHSTD9TC8
TD6,TD7,TD8
Perlautter-HayinanPoupko R.
Rabani J.Rabinovitz M.
Rappoport Z.Ratner M.A.Reisner G.M.Reller H.Richard E.Rishpon J.Rona P.Roten M.Roth 2.Rothaan A.Rubin A.J.Rubin M.B.
T4
Kl.
T3,WI2WJ12
WH2,WH3TA3
B. WJ5TA3
,TC4,TC11TD25.TD267.WL8.KL9
T1.WL4WI4TDlfcWH4TC4TF15TD1
TD15TD19TF12WN1CTDld
AbstractPage
6610972
20215013791176110
120
143137816978,33,
157134,5115051
34,
179.53,14588
15(->6511-73879111419588
,169
79,80143
155
65,7298
Rubini E.Rubinraut S.Rubinstein I.Rubinsztain Y.Ruhaan S.
Sagiv J.Sahai M.
AbstractNuaber
WK3.WK5WL5.WL6
TF16TD4
TC6.TC7
TB5TD19
Sarel S. TD22TD23TD24NK12Sarig S.Sassoon E.Scherz A.Scherz Z.Schlichter J.Schmuckler G.Schonberger E.Schorr M.rSchuler R.H.Schumann H.Segal R.Segal1 J.Selig H.Selinger 2.Shabtai D.Shai Y.Shamir J.Shani A.
180,131Shanzer A.176 Shapira-Cohen
Shapiro M.Shavit A.B.Shenhar A.Shepelev M.Shepelev 0.Sheves M.Shoef N.Shoham G.Shorr L.M.Shusterman A.Shvo Y.
TF6.WN17TC4TC8W05WN17TF19TG2
WN13.WN14
W4TD2
WK7,WK8WN4.KN5TF3.TF4
WK3.WK10NN20T06TF5
W6.TD9WK13
I. TD9TB4,TC5,WI1
WN2TG2WN3WN3WK6TD12TF18
WN4.WN5TF8,TF9,TF11
TD15.TD27
AbstractPage
1611771187667
6191941086569209200121123196
4274
16518710516120378
10744171816018512318618616484
120187,110:a, ,
,163,178
, 68
,95,96,170,200
,197
,166,188,106,168
, 81
, 66,142
,1S8,111,113, 99
218
AUTHOR INDEX (cont'd)
Abstract AbstractNumber Page
Abstract AbstractNumber Page
Siebrand W.Soffer A.Sonnenschein M.Spigelstein H.a-ebnik M.Stanger A.
TA7 55 Willner I. TC9,TC1O,TE1 70, 71,100WH1 133 Wisnontski-Knittel T. WJ4 149TA6 54 Wolaan Y. WO1 205TD5 77 Wongvisetsirikul N. TD22 94TD14 86 TD23.TD24 95, 96WL1 173 Woraser U. KK3.WK10 161,168
Taaarkin D. TD25 97Teitelbaua-Loyan D. WK5 163Tenne R. TB4.WH8 60,140Tobias H. WH1 133Toprowic; M. WJ15 158Tsiaering L. WG2 147Tulman R. WH2 134Turner J.A. WH5 137
Ukeles S.Utevski L.
Vaknin 0.Van Mil J.Varughese K.I.Vega S.Vitnof N.
WN8 191WN2 183
TF3 105W3 41
TE2 101TA8 56TE1 100
Yaain H.Yariv S.Yellin N.Yeshurun Y.Yinnon A.T.Yogev A,
Zadok E.Zaair L.O.Zinger B.Zoller U.Zurr Z.
WH3 135TC3.WO8 64,212TF1.TF2 103,104
TF3 105TB3 59
TC5.WJ13 66,158
WL5.WL6 177,178WK14 172\VH9 141TD1 73W7 45
Warshawsky A. TD12.TF16 84,118Weiner S. WK9 167Weinstein V. TD5 77Weinstock-Rosin M. WK5 163Weintraub E. WN14 197Weiss M. TF9.TF11 111,113Weissbuch I. W5 41Whaley K.B. TB2 58Wiener H. TD18 90Wilchek M. TD12 84Wilf J. WJ11 156
L219
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