Coordination compoundsCoordination compoundsCoordination compoundsCoordination compounds
มหาวทยาลยเกษตรศาสตร กาแพงแสนมหาวทยาลยเกษตรศาสตร กาแพงแสนมหาวทยาลยเกษตรศาสตร กาแพงแสนมหาวทยาลยเกษตรศาสตร กาแพงแสน
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Reference� J.E. Huheey, E.A. Keiter, and R.L. Keiter, Inorganic Chemistry; Principles of structure and Reactivity.
� F. A. Cotton and G. Wilkinson, Advanced Inorganic � F. A. Cotton and G. Wilkinson, Advanced Inorganic Chemistry.
� D.F. Shriver, P.W. Atkins, and C. H. Langford. , Inorganic Chemistry.
� B.E. Douglas, D.H. McDaniel, and J.J. Alexander, Concepts and models of inorganic Chemistry.
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Valence Bond Theory (VBT)
'()*+'+,-./01/23 1930 89: Linus Pauling ;<=/>?@?1AB1/ACDE 1950-1960
1ABI<JKK?L hybridization L=IDC?E d-orbitals KJO orbitals 1/8<I=;KC/K<?E1/ coordination compounds RJ/S='+,-KT9U=-2V/RJ/S=8W009T-/'8W-D-</XY
Metal ion + Ligand Coor. cpds.Metal ion + Ligand Coor. cpds.
Lewis acids
(metals or metal ions)
Lewis bases(ligands)
(e- pair acceptor) (e- pair donor)
Coordinate covalent bond
KL9--O.Lewis salt or adduct
4
'>?\@]^E-KT9K?L Hybridization ?
� ������� E ����� ��� ������������� overlap �� E !�� NH3� �%&�'�� hybrid orbital �� ��� �������./���0��� NH3 ���1'� pure orbital ���1'� pure orbital
6
Valence Bond Theory� Metal or metal ion: Lewis acid
� Ligand: Lewis base
� Hybridization of s, p, d orbitals
C.N. Geometry HybridsC.N. Geometry
4 tetrahedral
56
4
Hybrids
sp3
square planar dsp2
trigonal bipyramidal dsp3 or sp3doctahedral d2sp3 or sp3d2<--(4d)(3d)-->
7
Cr(CO)6 Cr = [Ar] 3d5 4s1
Fe(CO)5 Fe = [Ar] 3d6 4s2
Ni(CO)4 Ni = [Ar] 3d8 4s2
CO = 0
Diamagnetic
Cr = [Ar] 3d5 4s1
3d5 4s1 4p0
Cr* = [Ar]
Cr(CO)6 = [Ar]
d2sp3 hybrid Octahedral
3d6 4s0 4p0
8
Fe(CO)5 Fe = [Ar] 3d6 4s2
CO = 0
Fe = [Ar] 3d6 4s2
3d6 4s2 4p0
3d8 4s0 4p0
Fe* = [Ar]
Fe(CO)5 = [Ar]
dsp3 hybrid Trigonal bipyramid
9
Ni(CO)4 Ni = [Ar] 3d8 4s2
CO = 0
Ni = [Ar] 3d8 4s2
3d8 4s2 4p0
3d10 4s0 4p0
Ni* = [Ar]
Ni(CO)4 = [Ar]
sp3 hybrid Tetrahedral
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[Cr(H2O)6]3+ Cr = [Ar] 3d5 4s1
Cr = [Ar] 3d5 4s1
3d8 4s2 4p0
Cr3+ = [Ar] 3d33d3 4s0 4p0
[Cr(H2O)6]3+ = [Ar]
d2sp3 hybrid Octahedral
Innerparamagnetic
Cr3+ = [Ar] 3d3
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[Ni(H2O)6]2+ Ni = [Ar] 3d8 4s2
Ni = [Ar] 3d8 4s2
3d8 4s2 4p0
Ni2+ = [Ar] 3d83d8 4s0 4p0
4d0
4d0
[Ni(H2O)6]3+ = [Ar]
sp3d2 hybrid Octahedral
Outerparamagnetic
Ni2+ = [Ar] 3d8
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Co3+ [Ar]3d6
CoF63-
sp3d2 hybrid orbitals
electrons from F-, octahedral
3d 4s 4p
4d
Outer complex
Co3+ [Ar]3d6
CoF63-
d2sp3 hybrid orbitals
electrons from F-, octahedral
3d 4s 4p
Inner complex13
Outer ILo0 Inner ?� '>?K?L'9<0E
�Diamagnetic or paramagneticMagnetic Property
1845, Michael Faraday
paramagnetic, diamagnetic
Magnetic susceptibility Gouy
Faraday
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� 1AB'()*+0STO?:q<K?L'9<0E
� Inner complex or outer complex
� [Cr(H2O)6]3+ - - - - - > q<K?L'9<0E-2V/ paramagnetic
d2sp3 hybrid orbitals; inner complex
3d orbital @+ E t,>?KDC? 4d orbital RJ/S=L=IDC?E 0T00/u0E M-L 89: inner d U=;uvE;LEKDC? outer d
� [Ni(H2O)6]2+ - - - - - > q<K?L'9<0E-2V/ paramagnetic� [Ni(H2O)6]2+ - - - - - > q<K?L'9<0E-2V/ paramagnetic
sp3d2 hybrid orbitals; outer complex
3d orbital \@CDC?E ]^E;@B e- -9+,:D 2 e-U=UJOWwC ;tCKv'>?1IB 3d orbital DC?E
;WC orbital -9+:D-'C?/Jx/ X^,E\@C-R+:ER0 U^EtB0E1AB 4d orbital
� [CoF6]3- - - - - - > q<K?L'9<0E-2V/ paramagnetic
sp3 d2hybrid orbitals; Outer complex
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� K?LUJ98WLE.LB?Eu0E [CoF6]3- 'JxE.0E;OO Wo0 inner ;<= outer complex U=-KT9\9BKJO M '+,@+ U./. e- 1/ d orbital -2V/ 4, 5 ILo0 6 U=-2V/;OO19tB0ERTU?Ly?
�Hybrid orbital '+,1AB e- 1/ 3 d @+ E < 4d; 3d U^E-KT9RJ/S=KJO ligand \9B;uvE;LEKDC? 4d ∴∴∴∴K?L-KT9 inner complex U^E@+80K?.@?KKDC? outer complex
]B?@+ e- -9+,:D0:wC1/ 3d orbital K?L'+,U=/>? e- @?-uB?WwCKJ/tB0E1AB E .CD/I/^,E�]B?@+ e- -9+,:D0:wC1/ 3d orbital K?L'+,U=/>? e- @?-uB?WwCKJ/tB0E1AB E .CD/I/^,E
�]B?1AB 4d 1/K?L hybrid 1/K?L-KT9 hybridization @J/\@CtB0E-.+: E '+,U=OJEWJO1IB e- @?-uB?WwCKJ/ ∴∴∴∴ K?L-KT9 outer complex U^E@+80K?.@?KKDC? inner complex
�1st series d4, d6 U=-KT9 inner complex KJO ligand tC?E { :K-DB/ ligand '+,-2V/ H2O, F- U=\9B outer complex
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Metal '+,-KT9RJ/S=KJO ligand tJD19Kvt?@U=@+.@OJtT-2V/ paramagnetic /J,/Wo0 Fe3+
3d5
Fe = [Ar] 3d6 4s2
Fe3+ ;OO 1 = [Ar] 3d5
Fe3+ ;OO 2 = [Ar] 3d5
4s 4p 4d
Fe3+ ;OO 1 = [Ar] 3d5 6 Ligand -KT9 sp3d2 ; outer complex @+ 5 unpair e-
Fe3+ ;OO 2 = [Ar] 3d5 6 Ligand -KT9 d2sp3 ; inner complex @+ 1 unpair e-
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Pt2+ [Xe]4f145d8
PtCl42-
dsp2 hybrid orbitals
electrons from Cl-, square planar
5d8 6s0 6p
electrons from Cl-, square planar
Ni2+ [Ar]3d8
NiCl42-
sp3 hybrid orbitals
electrons from Cl-, tetrahedral
3d8 4s0 4p
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U|90C0/u0E'()*+ Valence bond
� VBT �� �1� CN = 4 �0. ��9/9 ':�'��������1�� ;������� :��� �<.: '���=�
� 9 '�� ��>�0. �������./���� cpx. ;/��B��� 1st transition cpx. FG��� 9 '�� ��>�0. �������./���� cpx. ;/��B��� 1 transition cpx. FG���&H� cpx. ��� ���
� 9 '�� ��>�0. �����/%/����:�� UV-Vis ����K�����./ d-d transition �� cpx.
� 9 '�� ��>�0. �������./ inner ���� outer complex 9/
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Crystal Field Theory (CFT)
1929, Hans Bethe
1935, modifications J.H. Vanvleck
MO + CF
Ligand Field Theory (LFT)
1950, apply CFT to transition metal complexes
successful in interpreting many important properties of complexes
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Crystal Field Theory (CFT)
� ;KB\u VBT O?E0:C?E\@C.?@?L]0STO?:\9B�.?L2L=K0O CN = 4 (8WLE.LB?E'+,\@C;/C/0/)
�.@OJtT;@C-I<vK�.@OJtT;@C-I<vK
�K?L-KT9.+
� RTU?Ly?;LEKL='>?L=IDC?E metal ion + ligand -2V/;LEKL='>?\}}~?.]Tt (electrostatic force) 2L=U|/TD-W<+:.u0E metal 9^E9w9 ligand (e-
u0E ligand) X,E ligand '>?I/B?'+,-2V/U|92L=U|\}}~? (point charge)
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-Ro,0U=-uB?1U0T'STR<u0E./?@\}}~?U?K2L=U|<Ou0E L '+,@+tC0 d orbitals 'JxE 5 u0E M U>?-2V/tB0E-uB?1ULw2LC?E 'T�'?EK?LUJ9tJD ;<=K?LKL=U?:u0E e- 1/ d orbitals
dz - y , dz - x2 2 2 2
egt2g
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Octahedral Complexes
� 0T'STR<./?@\}}~?U?K L (ligand field srength)
�4s @+L=9JO E .wEu^x/ ---------nondegenerate
�4p @+L=9JO E .wEu^x/ ;tC 3 orbitals '+,@+L=9JO E -'C?KJ/---------triply degenerate
�3d @+L=9JO E .wEu^x/ ;<=U?KK?L'+,@+ lobe A+xt?@;/D;K/ ;<=L=IDC?E;K/'>?1IB�3d @+L=9JO E .wEu^x/ ;<=U?KK?L'+,@+ lobe A+xt?@;/D;K/ ;<=L=IDC?E;K/'>?1IB-KT9K?L;:Ku0EL=9JO E
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d-Orbitals and Ligand Interaction(Octahedral Field)
�Ligands approach metald-orbitals pointing directly at axis are affected most by electrostatic interaction
d-orbitals not pointing directly at axis are least affected (stabilized) by electrostatic interaction
most by electrostatic interaction
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Splitting of the d orbitals by an octahedral field
t2g
eg
3/5∆∆∆∆o
2/5∆∆∆∆o
10Dq
+0.6 ∆∆∆∆O
-0.4 ∆∆∆∆OCenter of gravity, barycenter
eg ---> e = 2 orbitals '+@+ E -'C?KJ/ (doubly degenerate
∆∆∆∆O
eg ---> e = 2 orbitals '+@+ E -'C?KJ/ (doubly degenerate g = gerade K?LUJ9tJD'+,@+�w/:YK<?E.@@?tL (-WLo,0EI@?:}�EKYAJ/W<o,/-I@o0/KJ/
'+,L=:='?E'JxE.0E9B?/ (tLEKJ/uB?@) IC?EU?KU|9�w/:YK<?E-'C?KJ/ u = ungerade -WLo,0EI@?:}�EKYAJ/W<o,/tLEKJ/uB?@ 1/L=:=IC?EU?KU|9�w/:YK<?E-'C?KJ/
t2g---> t = 3 orbitals '+@+ E -'C?KJ/ (triply degenerate)∆∆∆∆O = crystal field splitting energy10Dq (D and q = 2LT@?y'+,\9BU?K.@K?L'?EWyTt�?.tLYu0E;OOU>?<0E\}}~?.]Tt:Y (electrostatic
model) 10 -2V/.J@2L=.T'ST�'+,\9BU?KK?LW>?/Dy)28
f-orbitals f ,f , f
f ,f , f
f
x3 y3 z3
x(y2-z2) y(x2-z2) z(x2-y2)
xyz
f ,f , ff ,f , f
f ,f , f
f
x3 y3 z3
x(y2-z2) y(x2-z2) z(x2-y2)
xyz29
Splitting of the d-orbitals by an octahedral field
t2g
eg
3/5∆∆∆∆o
2/5∆∆∆∆o
10Dqbarycenter
0.0
0.5
1.0
log εεεε
Frequency
20,300 cm-1
[Ti(H2O)6]3+ d1
t2g1eg
0 t2geg1
Purple
243 kJ/mol (∆∆∆∆o)
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Splitting energy of Tetrahedral complexs
� ∆∆∆∆ t < ∆∆∆∆ O /J,/Wo0 ∆∆∆∆ t ≈≈≈≈ 4/9 ∆∆∆∆ O
.?L2L=K0O cubic complexes
e
t2
2/5∆∆∆∆t
3/5∆∆∆∆t
∆∆∆∆t = 4/9 ∆∆∆∆o(high spin)
cube� .?L2L=K0O cubic complexes
� K?L split u0E d-orbitals U=-I@o0/KJO tetrahedral complexes
� Splitting energy U=-2V/ 2 -'C?1/ tetrahedral complexes
� 8 ligands <B0@L0O M ion = 2 ∆∆∆∆ t
cube
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Square Planar Crystal Field
Q -@o,0 L ;/D;K/ z :o9:?D00K > L 1/;/D;K/ x, y '>?1IBRJ/S='JxE 6 :?D\@C-'C?KJ/ (-.+:R<JEE?/RJ/S=) '>?1IB8WLE.LB?EOT9-O+x:DU?K octahedral -2V/ tetragonol -/o,0EU?Kq<KL='O Jahn-Teller Effect
QZ I<|900KU?K metal U=\9B square planar
Q -@o,0 L ;/D;K/ z :o9:?D00K > L 1/;/D;K/ x, y '>?1IBRJ/S='JxE 6 :?D\@C-'C?KJ/ (-.+:R<JEE?/RJ/S=) '>?1IB8WLE.LB?EOT9-O+x:DU?K octahedral -2V/ tetragonol -/o,0EU?Kq<KL='O Jahn-Teller Effect
QZ I<|900KU?K metal U=\9B square planar
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Splitting of the d orbitals in a square planar field (d8)
eg
z2
x2- y2
x2- y2
xyb2g
b1g
∆∆∆∆O
t2g
xz, yz
xy
z2
xz, yzeg
a1g
Removal of z ligands
Ni(CN)42-
, PdCl42-
,
Pt(NH3)42+
, PtCl42-
,
AuCl4-
0.656∆∆∆∆O
0.086∆∆∆∆O
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Electron Configuration in d-orbitals
∆E ∆E
Unpaired e- �� 2 orbitals ��� ���/� E :����� = ∆E
Model 1; weak field-high spin cpx.
Esystem = E0 + E0 + ∆∆∆∆E
E0 = E u0E e- ;tC<=tJD
∆o < P
Model 2; strong field � low spin cpx.
Esystem = E0 + E0 + P
P = pairing energy
∆o > P
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��Only the dOnly the d44 through dthrough d77 cases have both highcases have both high--spin and low spin configuration.spin and low spin configuration.
d4 high spinWeak Field
Electron Configuration for Octahedral complexes of metal Electron Configuration for Octahedral complexes of metal ion having dion having d11 to dto d1010 configuration.configuration.
d4 Strong Field
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Electron Configuration in Octahedral Field
�� Electron configuration of metal ion:Electron configuration of metal ion:
ss--electrons are lost first. electrons are lost first.
TiTi33++ is a dis a d11, V, V33++ is dis d22 , and Cr, and Cr33++ is dis d33
�� Hund's rule:Hund's rule:
First three electrons are in separate d orbitals with First three electrons are in separate d orbitals with their spins parallel.their spins parallel.their spins parallel.their spins parallel.
�� Fourth eFourth e-- has choice:has choice:
Higher orbital if Higher orbital if ∆∆∆∆∆∆∆∆ is small; High spinis small; High spin
Lower orbital if Lower orbital if ∆∆∆∆∆∆∆∆ is large: Low spin.is large: Low spin.�� Weak field ligandsWeak field ligands
Small Small ∆∆∆∆∆∆∆∆ , High spin complex, High spin complex�� Strong field LigandsStrong field Ligands
Large Large ∆∆∆∆∆∆∆∆ , Low spin complex, Low spin complex 37
Electron Configuration for tetrahedral complexes of metal ion Electron Configuration for tetrahedral complexes of metal ion having dhaving d11 to dto d1010 configuration.configuration.
e
t2
2/5∆∆∆∆t
3/5∆∆∆∆t
∆∆∆∆t = 4/9 ∆∆∆∆o
dxy, dyz, dzx
dz , dx - y2 2 2dz , dx - y2 2 2
Tetrahedral (Td) lacks a center of inversion 39
Electron Configuration for tetrahedral complexes of metal ion Electron Configuration for tetrahedral complexes of metal ion having dhaving d11 to dto d1010 configuration.configuration.
d3-d6 ---------- 1. high spin; weak field
2. low spin; strong field
2�UUJ:; ∆∆∆∆t ;<= P ∆∆∆∆t ≈ ≈ ≈ ≈ 4////9∆∆∆∆o ; ∆∆∆∆t /B0:
40
Electron Configuration for square planar complexesElectron Configuration for square planar complexes
d8 = Ni2+, Pd2+, Pt2+, Rh+1, Ir+1
∆ > P 42
Crystal-field Stabilization EnergyR<JEE?/'+,'>?1IB cpx. @+WD?@-.]+:L 0J/-/o,0EU?K./?@\}}~?U?K ligand '+,@+0T'STR<tC0K?L;:Ku0E d-orbital u0E metal ion '+,]wK ligand <B0@L0O89:I?U?K8WLE;OO0T-<vKtL0/1/\90=;KL@R<JEE?/u0E d-orbitals
CFSE = x(-0.4Dq) + y(+0.6Dq)+ PCFSE = x(-0.4Dq) + y(+0.6Dq)+ P
wherex = number of electrons in lower levelsy = number of electrons in upper levels
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Pairing energy� e- 2 tJDU=0:wC1/ orbital -9+:DKJ/\9BU=tB0E;
� 1. A/=;LEq<JK'+,-KT9U?K e- - e- (Internal repulsion energy)
� 2. R<JEE?/'+,@?A9-A:R<JEE?/'+,-.+:\21/K?LOJEWJO1IB e- @+ spin tLEuB?@ /Jx/Wo0 Exchange energy
� Energy of pairing electrons
� ΠΠΠΠcis the Coulombic energy of repulsion (always positive when pairing) and ΠΠΠΠe
is the quantum mechanical exchange energy (always negative).
ec Π+Π=Π
∆∆∆∆o ∆∆∆∆o
Weak field; ∆∆∆∆o < P (pairing energy)
High spin
Strong field; ∆∆∆∆o > P (pairing energy)
Low spin
c e
mechanical exchange energy (always negative).
� ΠΠΠΠerelates to the number of exchangeable pairs in a particular electron configuration. This term is
negative and depends on the number of possible states.
Determine ΠΠΠΠcand ΠΠΠΠe
for a d 5 metal complex (low and high spin).
44
Crystal Field Stabilization Energy, CFSE
LFSE = -0.4Dq -0.8Dq -1.2Dq
d1 d2 d3
LFSE =
High Spin Low Spin High Spin Low Spin
-0.6Dq -1.6Dq+P 0Dq -2.0Dq+2P
d4 d5
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Crystal Field Stabilization Energy, CFSE
LFSE =
High Spin Low Spin High Spin Low Spin
-0.4Dq+P -2.4Dq+3P -0.8Dq+2P -1.8Dq+3P
d6 d7
LFSE = -0.4Dq+P -2.4Dq+3P -0.8Dq+2P -1.8Dq+3P
LFSE = -1.2Dq+3P -0.6Dq+4P 0Dq+5P
d8 d9 d10
46
CFSE of Octahedral ComplexesExample Strong Weak
d0 Ca+2,Sc+3 0 up e- 0 Dq 0 upe- 0 Dqd1 Ti+3 1 -0.4 1 -0.4d2 V+3 2 -0.8 2 -0.8d3 Cr+3, V+2 3 -1.2 3 -1.2d4 Cr+2, Mn+3 2 -1.6 4 -0.6d4 Cr+2, Mn+3 2 -1.6 4 -0.6d5 Mn+2, Fe+3 1 -2.0 5 0d6 Fe+2, Co+3 0 -2.4 4 -0.4d7 Co+2 1 -1.8 3 -0.8d8 Ni+2 2 -1.2 2 -1.2d9 Cu+2 1 -0.6 1 -0.6d10 Cu+, Zn+2 0 0 0 0
47
Magnitude of CF Splitting (∆∆∆∆∆∆∆∆ or 10Dq)11. Metal: . Metal:
-- Larger metal larger Larger metal larger ∆∆∆∆∆∆∆∆-- Higher Oxidation State larger Higher Oxidation State larger ∆∆∆∆∆∆∆∆ -/o,0EU?K 2L=U|'+,/TD-W<+:.u0E -/o,0EU?K 2L=U|'+,/TD-W<+:.u0E M ion M ion @?KU=9E9w9 @?KU=9E9w9 L L '+,<B0@L0O1IB-uB?1K<B@?K '>?1IB-KT9K?L '+,<B0@L0O1IB-uB?1K<B@?K '>?1IB-KT9K?L spite spite @?K@?KRu(H2O)62+ ∆∆∆∆o = 19800 cm-1 Ru(H2O)63+ ∆∆∆∆o = 28600 cm-12 6 o
22. . Number and geometry of the ligands-- Octahedral Octahedral 6 6 ligandligand-- Tetrahedral Tetrahedral 4 4 ligandligand
33. . Nature of the metal ion--∆∆∆∆∆∆∆∆OO series series 22 > > ∆∆∆∆∆∆∆∆OO series series 11 ≈≈≈≈≈≈≈≈ 5050%%--∆∆∆∆∆∆∆∆OO series series 33 > > ∆∆∆∆∆∆∆∆OO series series 22 ≈≈≈≈≈≈≈≈ 2525%%∴∴∴∴∴∴∴∴ series series 22, , 3 3 @JK-2V/ @JK-2V/ low spin complex low spin complex -/o,0EU?K -/o,0EU?K ∆∆∆∆∆∆∆∆OO @+WC?@?K@+WC?@?K 48
44. Ligand: Spectrochemical series. Ligand: Spectrochemical seriesI-<Br-<S2-<SCN-<ClCl-- <NO<NO33
--< F< F-- <OH<OH--<ox<ox22--< H< H22O O < NCS< NCS-- <CH<CH33CN<NHCN<NH33
< en <bipy<phen< NO< en <bipy<phen< NO22-- < (N< (N--bonded)<phosph < CNbonded)<phosph < CN--<CO<CO
Weak field Ligand: Weak field Ligand: Low electrostatic interaction: small CF splitting.Low electrostatic interaction: small CF splitting.High field LigandHigh field Ligand: High electrostatic interaction: large CF splitting.: High electrostatic interaction: large CF splitting.
Spectrochemical series: Increasing Spectrochemical series: Increasing ∆∆∆∆∆∆∆∆ 49
Spectrochemical seriesSpectrochemical seriesI-<Br-<S2-<SCN-<ClCl-- <NO<NO33
--< F< F-- <OH<OH--<ox<ox22--< H< H22O O < NCS< NCS-- <CH<CH33CN<NHCN<NH33
< en <bipy<phen< NO< en <bipy<phen< NO22-- < (N< (N--bonded)<phosph < CNbonded)<phosph < CN--<CO<CO 50
Example� Using the Spectrochemical Series to Predict Magnetic Properties.
� How many unpaired electrons would you expect to find in the octahedral complex [Fe(CN)6666]]]]3333----????
51
e CFSE e CFSE
d1 t2g1 1 0.4 ∆∆∆∆o t2g
1 1 0.4 ∆∆∆∆o
d2 t2g2 2 0.8 ∆∆∆∆o t2g
2 2 0.8 ∆∆∆∆o
d3 t2g3 3 1.2 ∆∆∆∆o t2g
3 3 1.2 ∆∆∆∆o
Weak field Strong field
d3 t2g3 3 1.2 ∆∆∆∆o t2g
3 3 1.2 ∆∆∆∆o
d4 t2g3 eg
1 4 0.6 ∆∆∆∆o t2g4 2 1.6 ∆∆∆∆o
d5 t2g3 eg
2 5 0.0 ∆∆∆∆o t2g5 1 2.0 ∆∆∆∆o
d6 t2g4 eg
2 4 0.4 ∆∆∆∆o t2g6 0 2.4 ∆∆∆∆o
d7 t2g5 eg
2 3 0.8 ∆∆∆∆o t2g6 eg
1 1 1.8 ∆∆∆∆o
d8 t2g6 eg
2 2 1.2 ∆∆∆∆o t2g6 eg
2 2 1.2 ∆∆∆∆o
53
0T'STR<u0E./?@\}}~?U?K Ligand '+,@+tC0K?L;:KL=9JOR<JEE?/u0E d-orbital X^,E@+q<tC08WLE.LB?E ;<=.@OJtT-'0LY8@\9/[email protected].?L-ATEXB0/
� D-orbital '+,@+K?L;:Ku0EL=9JOR<JEE?/ '>?1IBK?LKL=U?:u0E e- L0O/TD-W<+:.u0E metal ion \@C-2V/'LEK<@ '>?1IB@+q<tC0:
� 1. LJ�@+\000/; metal ion '+,@+2L=U| +2 1/./?@\}}~? octahedral (high spin cpx.)
*
*
*
*
*
*
*
**
*
*
Ca2+ Sc2+ Ti2+ V2+ Cr2+ Mn2+ Fe2+ Co2+ Ni2+ Cu2+ Zn2+
LJ�@+\00
0/
Atomic no. .wEu^x/ LJ�@+<9<E (\9BU?K'()�+)
54
�&��� ���� ��Z �9����!��9����&��[\ 2+ !�� transition series 1
Mn = [Ar] 3d5 4s2
Mn2+ = [Ar] 3d5Zn = [Ar] 3d10 4s2
Zn2+ = [Ar] 3d10Ca = [Ar] 4s2
Ca2+ = [Ar]
eg
t2g
eg
t2g
eg
t2gd0 d5 d10
Sc = [Ar] 3d1 4s2
Sc2+ = [Ar] 3d1
t2g t2g t2g
d1
eg
t2g
t2g1 eg0 ---- e- 0:wC1/ t2g X^,E@+ lobe A+x\@CtLEKJOligand '>?1IB e- \@C\9BO9OJE;LE9^E9w9u0E2L=U| + '+,/TD-W<+:.KJO e- u0E ligand '>?1IB ligand ]wK9^E-uB?.wC/TD-W<+:.'>?1IBLJ�@+<9<E
55
Ti = [Ar] 3d2 4s2
Ti2+ = [Ar] 3d2
d2
eg
t2g
t2g2 eg0 ---- e- 0:wC1/ t2g X^,E@+ lobe A+x\@CtLEKJOligand '>?1IB 2e- \@C\9BO9OJE;LE9^E9w9u0E2L=U| + '+,/TD-W<+:.KJO 2e- u0E ligand '>?1IB ligand ]wK9^E-uB?.wC/TD-W<+:.'>?1IBLJ�@+<9<E
V = [Ar] 3d3 4s2
V2+ = [Ar] 3d3 t2g3 eg0
Cr = [Ar] 3d5 4s1
Cr2+ = [Ar] 3d4
d4
eg
t2g
t2g3 eg1 ---- 1e- 0:wC1/ eg X^,E@+ lobe A+xtLEKJOligand '>?1IB 1e- O9OJE;LE9^E9w9u0E2L=U| + '+,/TD-W<+:.KJO 1e- u0E ligand '>?1IBLJ�@+-RT,@
Fe = [Ar] 3d6 4s2
Fe2+ = [Ar] 3d6 t2g4 eg2 -------e-'+,-RT,@1/ t2g :JE-I@o0/KLy+ Ti2+
56
Co2+ = [Ar] 3d7
Ni2+ = [Ar] 3d8t2g5 eg2
t2g6 eg20STO?:-AC/-9+:DKJO Fe2+
Cu2+ = [Ar] 3d9 eg t2g6 eg3 ---- e- '+,-RT,@u^x/0:wC1/ eg X^,E@+ lobe A+xtLEKJO ligand '>?1IB e- O9OJE;LE9^E9w9u0E
t2g
tLEKJO ligand '>?1IB e O9OJE;LE9^E9w9u0E2L=U| + '+,/TD-W<+:.KJO e- u0E ligand '>?1IBLJ�@+-RT,@
57
Jahn-Teller Effect
1937 Jahn & Teller
-Lw2LC?Eu 0E8@-<K|<RDK non-linear X^,E@+ e- 0:wC1/K<|C@ orbital 19 { '+,@+L=9JO E -'C?KJ/tB0EOT9-O+x:D\2 -Ro,0'>?1IBWD?@-'C?KJ/u0EL=9JO E u0E orbital 'JxEI<?:I@9\2 -KT9 orbital '+,@+ E t,>?KDC?-9T@ molecule @+WD?@-.]+:L@?Ku^x/
-8WLE.LB?EOT9-O+x:D--> .@@?tL<9<E ;<=@+K?L;:Ku0E -8WLE.LB?EOT9-O+x:D--> .@@?tL<9<E ;<=@+K?L;:Ku0E degenerate electronic state '+,\@C-.]+:L/Jx/
--9T@RJ/S='JxE 6 u0E M-L :?D-'C?KJ/ -@o,0-KT9 Jahn Teller effect '>?1IB M-L :?D\@C-'C?KJ/ U=-KT9\9B 2 ;OO
1. z-out: Ligand ;/D;K/ z :o9:?D00K\2
2. compression ILo0 z-in: Ligand ;/D;K/ z ]wKI9.Jx/<E\258
K?L-KT9 Jahn Teller Effect
Q -@o,0 ligand 1/;/D;K/ z ]wK:o9:?D00K -D<?-KT9 distortion ./?@\}}~?U?K ligand 1/;/D;K/ z U=/B0:KDC?;K/0o,/
Qd-orbital '+,@+;K/ z -2V/0EWY2L=K0O @+L=9JO E t,>?KDC? d-orbital '+,\@C@+;K/ z -2V/0EWY2L=K0O
-Distort z-out \9B complexes '+,@+ 4 RJ/S=.Jx/ 2 RJ/S=:?D
-Distort z-in \9B complexes '+,@+ 4 RJ/S=:?D 2 RJ/S=.Jx/59
Cu2+ @JK-KT9 Jahn Teller effect
Cu2+ = [Ar] 3d9-----------> t2g6eg3
eg eg
dx2-y2, dz2 dz2 , dx2-y2
t2g t2gdxy , dyz ,dzxdxy , dyz ,dzx
e- 2 tJD1/ dx2-y2 X,EU=O9OJE;LE9^E9w9 Proton '+,/TD-W<+:.u0E metal ion KJO e- u0E ligand @?KKDC?1/;/D;K/ z '+,@+ e- 1 tJD '>?1IB ligand 1/;/D;K/ z ]wK9^E-uB?1K<B metal ion @?KKDC? ligand 1/;/D;K/ xy '>?1IB\9B complexes '+,@+ 4 RJ/S=:?D 2 RJ/S=.Jx/
t2g6eg3 t2g6eg3A B4 ��1 2 ��^� 2 ��1 4 ��^�
e- 2 tJD1/ dz2 X,EU=O9OJE;LE9^E9w9 Proton '+,/TD-W<+:.u0E metal ion KJO e- u0E ligand @?KKDC?1/;/D;K/ xy X,E ligand 1/;/D;K/ xy ]wK9^E-uB?1K<B metal ion @?KKDC?;K/ z '>?1IB\9B complexes '+,@+ 2 RJ/S=:?D 4 RJ/S=.Jx/ (RO@?K)60
Jahn-Teller splitting
z-in z-out
compressed elongatedoctahedron (along the z-axis)
- Spitting energy U=@+ δδδδ1, δδδδ2 < ∆∆∆∆o61
Jahn Teller Distortions
� Orbital degeneracy: for octahedral geometry these are:� t
2g
3eg
1 eg. Cr(II), Mn(III) High spin complexes� t
2g
6eg
1 eg. Co(II) (low spin), Ni(II)� t
2g
6eg
3 eg. Cu(II)� t2g
6eg
3 eg. Cu(II)
� basically, when the electron has a choice between one of the two degenerate e
g orbitals, the geometry will distort to lower the energy
of the orbital that is occupied.� result is some form of tetragonal distortion
� Cu (II) -KT9K?LOT9-O/@?KU/-.@o0/DC?-2V/ Square planar62
Jahn-Teller Effect + Metal (excited state)� 8<I='+,0:wC1/.�?D=/+xU=@+0?:|0:wC.Jx/@?K '>?1IB8WLE.LB?Eu0E cpx. '+,
equilibrium -KT90:wC\9BAJ,D-D<?.Jx/@?K Lw2LC?EOT9-O/\2K<JO@?-2V/;OO-9T@0:C?ELD9-LvD -L+:KDC? �Jahn-Teller effect ;OO dynamic
� \9B spectrum -2V/ band KDB?E \@C@+.@@?tL -AC/ � \9B spectrum -2V/ band KDB?E \@C@+.@@?tL -AC/ � [Ti(H2O)63+] t2g1eg0 ------ex.------> t2g0eg1
� [Fe(H2O)62+] (high spin) t2g4eg2 ------ex.------> t2g3eg3
� [CoF6]3- (high spin) t2g4eg2 ------ex.------> t2g3eg3
63
The color of [Ti(H2O)6]3+
20300 (cm-1)
20300 cm-1 x 1 kJ mol-1 = 243 kJ mol-183.6 cm-1
υ1υ2
* ��� � Jahn Teller effect [�9/ spectra ��� �9��' peak
20300 cm x 1 kJ mol = 243 kJ mol83.6 cm-1
64
Absorption spectrum of K3CoF6 illustrating transitions from the ground state to the Jahn Teller split excited state
65
Dynamic Jahn-Teller effect� q<'?E x-ray crysallography-------Cu2+ 0T00/O?EtJD0o,/ { -AC/ Mn3+ WDL@+;K/ z :?DKDC?
;K/ x ;<= y (t?@I<JK Jahn-Teller effect)� ;tCRODC? [Cu(en)3]2+ ILo0 Mn(acac)3 @+ 6 RJ/S=:?D-'C?KJ/;<= E ;'O\@CtC?EKJ/-<: -/o,0EU?K
2L?K�K?LyY Dynamic Jahn-Teller effect� KLy+ Cu2+ --->RJ/S=1/;K/ z '+,-KT9 Jahn-Teller effect .?@?L];<K-2<+,:/ILo0-2<+,:/\2
@?X^,EKJ/;<=KJ/ (interchange) L=IDC?ERJ/S= Cu-N 'JxE 6� K?L-2<+,:/\2@?0?U-2V/;OO vibration ILo0 rotation� K?L-2<+,:/\2@?0?U-2V/;OO vibration ILo0 rotation� ]B?0JtL?K?L interchange -KT9\9B-LvD@?K U=\@C.?@?L]O0KWD?@;tKtC?Eu0EWD?@:?DRJ/S=1/;K/
tC?E { \9B (\@COT9-O/-<:)� K?L-2<+,:/\2@?L=IDC?ERJ/S= W<B?:KJODC?RJ/S=-KT9K?L rotate \2 900 (pseudorotation)
� pseudorotation ux/KJO T [Cu(H2O)6]2+ (e.s.r. '+, T < 20 K-------tetragonal distortion)
(e.s.r. '+, T >60 K-------Octahedral \@C-KT9 distort -RL?=0JtL?-LvDK?L-KT9 pseudorotation -KT9-LvD@?K)
� Mn(acac)3 or K2Pb[Cu(NO2)6] -2V/tB/
66
Hydrati
on en
ergy (k
J/mol-
1 )
*
**
* **
**
*
* *
**
* ** U?KK?L'9<0E* WC?'+,-0? LSFE 00K;<BD
Thermodynamic !�����:����/� �������!�� d-orbitalHy
drati
on en
ergy (k
J/mol
*
Ca2+ Sc2+ Ti2+ V2+ Cr2+ Mn2+ Fe2+ Co2+ Ni2+ Cu2+ Zn2+
R<JEE?/'+,-K+,:DuB0E Wo0 CFSE
M2+ + 6H2O [M(H2O)62+(aq) ; E -> Heat of hydration
Ca2+, Mn2+, Zn2+ (d0, d5, d10) @+ CFSE = 0
U|9.+9>?Wo0@+WC? CFSE ≠≠≠≠ 0
-@o,0-0?WC? CFSE @?<OKJO Heat of hydration U=\9BU|9O/-.B/tLE 67
Lattice en
ergy (k
J/mol-
1 )
**
*
* **
** ** U?KK?L'9<0E
* WC?'+,-0? LSFE 00K;<BD
Lattice energyLa
ttice en
ergy (k
J/mol
*
Ca2+ Sc2+ Ti2+ V2+ Cr2+ Mn2+ Fe2+ Co2+ Ni2+ Cu2+ Zn2+
R<JEE?/'+,-K+,:DuB0E Wo0 CFSE
Ca2+, Mn2+, Zn2+ (d0, d5, d10) @+ CFSE = 0
U|9.+9>?Wo0@+WC? CFSE ≠≠≠≠ 0
-@o,0-0?WC? CFSE @?<OKJO lattice energy U=\9BU|9O/-.B/tLE68
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