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Inorganica Chimica Acta 358 (2005) 4371–4388
Syntheses, structures and vibrational spectroscopy of some 1:1and 1:2 adducts of silver(I) oxyanion salts with 2,2 0-bis(pyridine)
chelates
Graham A. Bowmaker a,*, Effendy b,c, Siti Marfuah c, Brian W. Skelton b,Allan H. White b
a Department of Chemistry, University of Auckland, Private Bag 92019, Auckland, New Zealandb Chemistry M313, The University of Western Australia, Crawley, WA 6009, Australia
c Jurusan Kimia, FMIPA Universitas Negeri Malang, Jalan Surabaya 6, Malang 65145, Indonesia
Received 22 February 2005; accepted 4 April 2005
Available online 2 June 2005
Dedicated to Professor Hubert Schmidbaur.
Abstract
Syntheses and room-temperature single-crystal X-ray structure determinations are recorded for a number of adducts of 1:1 stoi-
chiometry of silver(I) oxyanion salts (perchlorate, nitrate, trifluoroacetate (�tfa�) (increasing basicity)) with 2,2 0-bis(pyridine) ligands
(2,2 0-bipyridyl, �bpy�; 2,2 0-biquinolyl, �bq�; 2,2 0-dipyridylketone, �dpk�; 2,9-dimethylphenanthroline, �dmp�). The adducts take two
forms: (a) neutral mononuclear molecules, in which the 2,2 0-bis(pyridine) ligand behaves as a chelate, with the silver coordination
number dependent on the denticity of the anion; these are Agtfa:bpy (1:1) and AgClO4:bq (1:1) (and various (ionic) acetonitrile or
pyridine solvates AgClO4:bq/dmp:MeCN/py (1:1:1), in which the solvent molecules are coordinated); and (b) one-dimensional poly-
mers. The latter are diverse: in AgClO4:bpy, dpk (1:1), the anion is discrete, the polymer made up of an array of two-coordinate
silver atoms linked by bpy ligands twisted about their central connecting element. In AgNO3:bpy, bq (1:1), the bpy ligands are che-
lating with the oxyanions bridging, cf. previously reported AgNO3:dpk (1:1), in which the nitrate chelates the metal, with the dpk
bridging, chelating N,O to one silver, while the other nitrogen bridges to the next. With Agtfa, a novel binuclear adduct has been
isolated in conjunction with the hydrated ligand, Agtfa:dpk:(dpk Æ H2O) (1:1:2). The far-IR spectra of several of these complexes
show bands that can be assigned to the m(AgN) modes, the positions of these bands correlating well with the relative Ag–N bond
lengths.
Syntheses and single-crystal X-ray structural characterizations are also reported for various adducts of silver(I) perchlorate, nitrate
and trifluoromethanesulfonate with bpy, bq, �phen� (=1,10-phenanthroline), and �dmp�, of stoichiometry AgX:L (1:2). In each case the
complex is ionic [AgL2]X; the silver atom is four-coordinate, but diverse and remarkable variations in stereochemistries associated
with changes in the interligand N–Ag–N angles, presumably influenced by the different packing arrangements, are observed.
� 2005 Elsevier B.V. All rights reserved.
Keywords: X-ray crystal structures; Vibrational spectroscopies; N,N0-Aromatic chelates
0020-1693/$ - see front matter � 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2005.04.001
* Corresponding author. Tel.: +64 9373 7599; fax +64 9373 7422.
E-mail address: ga.bowmaker@auckland.ac.nz (G.A. Bowmaker).
1. Introduction
In the preceding pair of papers [1,2], we have struc-
turally characterized a range of adducts of silver(I) oxy-
anion salts, AgX, for a range of oxyanion basicities
4372 G.A. Bowmaker et al. / Inorganica Chimica Acta 358 (2005) 4371–4388
represented by perchlorate, nitrate and carboxylate
(” trifluoroacetate, �tfa�), predominantly with a variety
of pyridine (�py�) (or on occasion piperidine (�pip�)) basesvariously substituted in the 2- (and, sometimes 6-) posi-
tions with non- or coordinating substituents. With
non-coordinating (and, occasionally coordinating) sub-stituents (inclusive of parent H), the predominant form
recorded was of the type [AgL2]+X�, L behaving as a
unidentate py-N (or pip-N) donor, with oxyanion inter-
actions of varying extents; with sterically less- or un-hin-
dered pyridine forms, oligo- or poly-nuclear aggregates
become possible, with increased metal coordination
number, by anion bridging, this latter tendency being
enhanced by increasing counterion basicity. Whereappropriately competitive substituents are found in the
2-position of the ligand, such aggregates may arise by
ligand bridging, even in the context of two-coordinate
silver, and, also, if the substituent has the flexibility
and capacity to form five-membered or larger rings,
the ligand may bond as a chelate.
Such is a common mode of binding with a number
of familiar bidentate ligands arising out of a pair oflinked py groups. With 1,10-phenanthroline, �phen�,and its simple hindered 2,9-dimethyl substituted deriv-
ative �dmp�, the ligand is necessarily almost universally
a chelating bidentate ligand by virtue of the rigid fu-
sion of the ligand rings so that they lie in proximity
to each other, forming with any associated metal atom
a five-membered ring, formally paralleled in some sense
by the chelating arrays described in the previous paperwith the ligands 2-aminomethylpyridine, H2NCH2 ÆC5H4N (�nmp�) and 2-acetylpyridine, CH3 Æ CO ÆC5H4N (�acp�). The latter differ, however, in having a
degree of flexibility not available in phen, and if those
arrays are to be extended to an aromatic/oligo-pyridyl
N,N 0-donor array, then that is more closely paralleled
with L = 2,2 0-bipyridyl, �bpy�, and its relatives; a num-
ber of the more esoteric and synthetically difficult ofthese have been exploited by adherents of the more ar-
cane fields of �supramolecular chemistry� and �crystalengineering�, seemingly bypassing equally interesting
and more fundamental possibilities offered by �straight-forward� complexes of the simpler parent ligands, such
as those presented here and elsewhere [3] in contempo-
raneous papers. Accordingly, we have sought to extend
the previous work to encompass complexes of bpy andits relatives, these being capable of behaving as che-
lates, or, by virtue of their flexibility about the central
bond (bpy and �bq� (2,2 0-biquinolyl) themselves crystal-
lize centrosymmetrically in the trans-form) [4], bridging
arrays. Adducts of the form AgX:L (1:n), are most
familiar for n = 2; for the simpler of such ligands, a
rather wide range of 1:2 AgX:L complexes have al-
ready been structurally described, all of the form[AgL2]X(ÆS) (S = solvent), L functioning as an essen-
tially symmetrical chelate, with the Ag(N2)2 co-ordina-
tion environmental parameters varying fairly widely in
respect to internal steric changes within the ligand and
external forces in the systems L/X = bpy/NO3 (mono-
hydrate) [5], 6,6 0-dibromo-bpy/BF4 [6], 5,5 0-dicyano-
bpy/BF4, PF6 [7], and 4,4 0,6,6 0-tetramethyl-bpy/BF4
[8], phen/F3CSO3 (= �tfs�) [11], phen/F3CCO2 (monohy-drate) [9] as well as dmp/BF4 [10], and more complex
arrays [12]. In complexes with n = 1, the silver atom
is rationed to a (maximum) donor aliquot of two py
type nitrogen atoms if they are �normal� r-donors.We have sought to continue our characterization of
such arrays for the X = ClO4, NO3, tfa series by
extending the range of adducts of 1:1 stoichiometry
derivative of bpy with the ligands bpy, bq, and, inmore extended mode, offering the possibility of six-
membered ring chelates, 2,2 0-dipyridylketone, �dpk�,and structurally characterizing them by single-crystal
diffraction studies and vibrational spectroscopy. The
similar ligand, 2,2 0-dipyridylamine, �dpa�, was also ex-
plored as a possible complexing agent, but well-defined
crystalline adducts were not obtained; further, the sus-
ceptibility of dpk to hydrolysis forming �(dpk Æ H2O)�was recognized as well known [13]. Adducts of the
form AgX:L (1:1) already structurally described for
the simpler ligand systems of this type comprise a di-
verse and sporadic range of X/L combinations: (bpy/
SCN) [14], 5,5 0- and 6,6 0-dimethyl-bpy/NO3, ClO4
[15,16], dmp/NO3 [17], dpk/NO3 [18], BF4 [19], with di-
verse forms: anion-bridged polymer, discrete monomer,
ligand-bridged polymer, respectively (both polymerforms one-dimensional). In these 1:1 species, more
complex ligands such as 5,5 0-dicyano-bpy [7] may
incorporate functionalities which themselves become
part of the arrays (intentionally so), as is also adum-
brated by the behaviour of the dpk ligand. Turning
to adducts of 1:2 stoichiometry, MX:L (1:2), for simple
unhindered ligands derivative of 2,2 0-bipyridyl (�bpy�)or 1,10-phenanthroline (�phen�), the only structures re-corded for any univalent silver(I) complexes with sim-
ple anions of the above type of mononuclear form
are (as above) AgNO3:bpy (1:2) (monohydrate) [5],
Agtfs:phen (1:2) [9], Agtfa:phen (1:2) (ÆH2O) (�tfa� = F3-
CO2) [10], and AgBF4:dmp (1:2) (dichloromethane sol-
vate) [11] for silver. While in one sense, a single
example for the structure of each cation type may be
considered definitive, we have been interested to ob-serve among the various forms the diversity of stereo-
chemical parameters exhibited, presumably in
association with the various factors arising from crystal
packing, an aspect itself frequently of considerable
interest in consequence of the propensity of the planar
extended aromatic moieties to constitute a factor of
significant influence. Accordingly, we have revisited
these 1:1 and 1:2 systems more comprehensively witha view to establishing their nature, and, more particu-
larly, the manner in which any diversity of cation
G.A. Bowmaker et al. / Inorganica Chimica Acta 358 (2005) 4371–4388 4373
parameters is reflected in their spectroscopy (1:1 com-
plexes) and stereochemistry.
2. Experimental
2.1. Synthesis
All materials were obtained as colourless crystals by
the crystallization of the appropriate millimolar stoichi-
ometry of salt and ligand from solution in the specified
solvent (ca. 10 ml, reduced as/if needful). (Syntheses of a
number have been previously recorded (see below).) Sat-
isfactory analytical data were obtained for bulk samplesfor the following new compounds.
Agtfa:bpy (1:1). Found: C, 38.4; H, 2.0; N, 7.7.
C12H8AgF3N2O2 requires: C, 38.23; H, 2.14; N, 7.43%.
Solvent: methanol.
AgClO4:bq (1:1). Found: C, 47.1; H, 2.6; N, 8.3.
C18H12AgClN2O4 requires: C, 46.63; H, 2.61; N,
6.04%. Solvent: acetone.
AgClO4:bq:MeCN (1:1:1). Found: C, 47.6; H, 2.9;N, 8.3. C20H15AgClN3O4 requires: C, 47.60; H, 3.00;
N, 8.32%. Solvent: acetonitrile.
AgNO3:bq (1:1). Found: C, 50.6; H, 2.7; N, 9.8.
C18H12AgN3O3 requires: C, 50.73; H, 2.84; N, 9.86%.
Solvent: acetonitrile.
AgClO4:dpk (1:1). Found: C, 33.7; H, 1.8; N, 7.1.
C11H8AgClN2O5 requires: C, 33.75; H, 2.06; N, 7.16%.
Solvent: acetonitrile.Agtfa:dpk:(dpk Æ H2O) (1:1:2). Found: C, 43.2; H,
2.7; N, 8.3. C37H28Ag2F6N6O9 requires: C, 43.13; H,
2.74; N, 8.16%. Solvent: ethanol.
2.2. 1:2 complexes
Following the literature syntheses as indicated in a
number of cases, the appropriate silver(I) salt was crys-tallized with a slight stoichiometric excess of ligand on a
millimolar scale from a few ml of the specified solvent (if
other than ethanol).
AgClO4:bpy (1:2). Found: C, 46.2; H, 3.2; N, 10.7.
C20H16AgClN4O4 requires: C, 46.23; H, 3.10; N,
10.78%. Solvent: CHCl3.
AgClO4:phen (1:2). Found: C, 51.0; H, 3.0; N, 9.7.
C24H16AgClN4O4 requires: C, 50.78; H, 2.84; N,9.87%. Solvent: CHCl3.
AgNO3:dmp (1:2). Found: C, 57.5; H, 4,2; N, 12.1.
C28H24AgN5O3 requires: C, 57.35; H, 4.13; N, 11.94%.
Agtfs:dmp (1:2). Found: C, 50.8; H, 4.0; N, 8.2.
C29H24AgF3N4O3S requires: C, 51.72; H, 3.59; N,
8.32%. Solvent: ethanol/acetonitrile.
2.3. Spectroscopy
General procedural details are given in [1].
2.4. Structure determinations
2.4.1. General procedure
For general procedure, see accompanying reference
[1]; full .cif depositions reside with the Cambridge Crys-
tallographic Data Centre, CCDC Nos. 260779–260796;specific crystal/refinement details are as follows.
2.4.1.1. 1:1 complexes.
2.4.1.1.1. AgClO4:bpy (1:1). C10H8AgClN2O4,
M = 363.5. Single counter instrument; T ca. 295 K.
Tetragonal, space group I41/acd ðD204h; No: 142Þ,
a = 19.700(5) A, c = 12.705(2) A, V = 4931 A3. Dcalc
(Z = 16) = 1.958 g cm�3. lMo = 18.6 cm�1; specimen:0.10 · 0.15 · 0.28; Tmin,max = 0.79, 0.86. 2hmax = 50�;Nt = 3414, N = 889 (Rint = 0.038), No = 496; R = 0.041,
Rw = 0.056. |Dqmax| = 0.46(2) e A�3. Crystallization sol-
vent: acetonitrile.
2.4.1.1.2. AgNO3:bpy (1:1). C10H8AgN3O3, M =
326.1. CCD instrument; T ca. 300 K. Monoclinic, space
group P21/n ðC52h; No:14ðvariantÞÞ, a = 8.7310(8) A,
b = 7.0211(7) A, c = 18.017(2) A, b = 100.508(1)�, V =1086 A3. Dcalc (Z = 4) = 1.994 g cm�3. lMo = 18.6
cm�1; specimen: 0.40 · 0.31 · 0.07; Tmin/max = 0.65.
2hmax = 58�; Nt = 12594, N = 2740 (Rint = 0.024), No =
2386; R = 0.028, Rw = 0.020. |Dqmax| = 0.84(1) e A�3.
Variata. (x,y,z,Uiso)H were refined. The crystalliza-
tion solvent was methanol.
2.4.1.1.3. Agtfa:bpy (1:1). C12H8AgF3N2O2,
M = 377.1. CCD instrument; T ca. 300 K. Monoclinic,space group P21/n, a = 7.2401(9) A, b = 14.957(2) A,
c = 12.045(1) A, b = 103.749(2)�, V = 1267 A3. Dcalc
(Z = 4) = 1.977 g cm�3. lMo = 16.3 cm�1; specimen:
0.14 · 0.10 · 0.09; Tmin/max = 0.52. 2hmax = 58�;Nt = 14769, N = 3190 (Rint = 0.041), No = 1749;
R = 0.044, Rw = 0.048. |Dqmax| = 1.14(3) e A�3.
Variata. (x,y,z,Uiso)H were refined.
2.4.1.1.4. AgClO4:bq (1:1). C18H12AgClN2O4, M =463.6. CCD instrument; T ca. 300 K. Monoclinic, space
group P21/c ðC52h; No:14Þ, a = 8.3835(7) A, b =
11.373(1) A, c = 17.413(2) A, b = 97.398(1)�, V = 1646
A3. Dcalc (Z = 4) = 1.870 g cm�3. lMo = 14.1 cm�1; spec-
imen: 0.33 · 0.13 · 0.16; Tmin/max = 0.82. 2hmax = 58�;Nt = 18379, N = 4154 (Rint = 0.020), No = 2368;
R = 0.037, Rw = 0.043. |Dqmax| = 0.99(2) e A�3.
Variata. (x,y,z,Uiso)H were refined.2.4.1.1.5. AgClO4:bq:MeCN (1:1:1). C20H15AgCl-
N3O4, M = 504.7. Single counter instrument; T ca. 153
K. Orthorhombic, space group Pbcn ðD142h; No: 60Þ,
a = 21.607(1) A, b = 13.0716(8) A, c = 13.5396(8) A,
V = 3824 A3. Dcalc (Z = 8) = 1.753 g cm�3. lMo = 12.3
cm�1; specimen, Tmin/max = 0.85. 2hmax = 70�;Nt = 78396, N = 8420 (Rint = 0.036), No = 6142;
R = 0.038, Rw = 0.043. |Dqmax| = 1.37(4) e A�3.2.4.1.1.6. AgClO4:bq:py (1:1:1). C23H17AgClN3O4,
M = 542.7. Monoclinic, space group P21/c,
4374 G.A. Bowmaker et al. / Inorganica Chimica Acta 358 (2005) 4371–4388
a = 8.8046(4) A, b = 14.8416(7) A, c = 17.1907(8) A,
b = 92.574(1)�, V = 2061 A3. Dcalc (Z = 4) = 1.749 g
cm�3. lMo = 11.5 cm�1; specimen: 0.16 · 0.12 · 0.10;
Tmin/max = 0.85. 2hmax = 75�; Nt = 42263, N = 10789
(Rint = 0.035), No = 8072; R = 0.031, Rw = 0.034.
|Dqmax| = 0.94(8) e A�3.Variata. (x,y,z,Uiso)H were refined. The complex was
crystallized from MeCN/py solution.
2.4.1.1.7. AgNO3:bq (1:1). C18H12AgN3O3,
M = 426.2. CCD instrument; T ca. 153 K. Monoclinic,
space group P21/c, a = 10.9336(8) A, b = 8.260(6) A,
c = 17.923(1) A, b = 104.027(2)�, V = 1566 A3. Dcalc
(Z = 4) = 1.808 g cm�3. lMo = 13.1 cm�1; specimen:
0.39 · 0.22 · 0.12; Tmin/max = 0.71. 2hmax = 75�;Nt = 31812, N = 8185 (Rint = 0.029), No = 6093;
R = 0.034, Rw = 0.046. |Dqmax| = 1.56(6) e A�3 (x, y, z,
Uiso)H were refined.
2.4.1.1.8. AgClO4:dmp:MeCN (1:1:1). C16H15AgCl-
N3O4, M = 456.6. CCD instrument; T ca. 153 K. Mono-
clinic, space group P21/c, a = 12.140(2) A, b = 19.315(3)
A, c = 7.340(1) A, b = 107.459(4)�, V = 1662 A3.
Dcalc = 1.825 g cm�3. lMo = 14.0 cm�1; specimen:0.35 · 0.17 · 0.09; Tmin/max = 0.75. 2hmax = 75�;Nt = 31489, N = 8725 (Rint = 0.036), No = 6676;
R = 0.037, Rw = 0.050. |Dqmax| = 1.64(6) e A�3. Crystal-
lization solvent: acetonitrile.
Variata. The compound is isomorphous with its cop-
per(I) ClO4� and BF4
� counterparts [20,21].
2.4.1.1.9. AgClO4:dpk (1:1). C11H8AgClN2O5,
M = 391.5. CCD instrument; T ca. 300 K. Monoclinic,space group Cc ðC4
s ; No: 9Þ, a = 12.255(3) A, b =
33.465(8) A, c = 9.837(2) A, b = 94.511(4)�, V = 4022
A3. Dcalc (Z = 4) = 1.940 g cm�3. lMo = 17.2 cm�1; spec-
imen: 0.25 · 0.22 · 0.22; Tmin/max = 0.79. 2hmax = 58�;Nt = 44637, N = 5103 (Rint = 0.022), No = 3162;
R = 0.039, Rw = 0.045. |Dqmax| = 0.66(5) e A�3.
Variata. A recent study of the tetrafluoroborate ana-
logue AgBF4:dpk (1:1) shows it to be quasi-isomor-phous with the present [19]. It is monoclinic C2/c,
a = 12.129(1) A, b = 11.116(1) A, c = 9.716(1) A,
b = 93.95(1)�, V = 1307 A3, Z = 4, the silver atoms lying
on crystallographic inversion centres, as also do the bor-
on atoms, so that the anions are disordered. We find the
cell of the present structure to be related by a tripling of
the b axis with a correspondingly large body of addi-
tional weak data, presenting concomitant difficulties inmodelling and refinement. As presented, the favoured
model is in space group Cc, none of the atoms disposed
on special positions (there being none in that space
group), the cationic component disposed in two strands.
One, containing moiety 1, generates a glide related
neighbour within the c dimension of the cell; the other,
comprised of both moieties 2, 3 spans that dimension.
Perchlorates 2, 3 were modelled with their oxygen atomsdisposed over two sets of sites, set with equal occupan-
cies after trial refinement; for perchlorate 1, although
displacement parameters were very high, disorder could
not be resolved. Although the expected correlation ef-
fects were evident (care in interpreting resultant param-
eters!), refinement was relatively stable, maximum shift/
error at convergence being 0.15. Unsurprisingly,
refinement of the absolute configuration was not defini-tive, so that in the final cycles ðhklÞ and ð�h�k�lÞ were
merged.
2.4.1.1.10. Agtfa:dpk:(dpk Æ H2O) (1:1:2). C37H28-
Ag2F6N6O9, M = 1030.4. CCD instrument; T ca. 300
K. Triclinic, space group P�1, a = 12.771(3) A,
b = 12.922(3) A, c = 14.158(3) A, a = 65.855(4)�,b = 71.923(4)�, c = 67.074(4)�, V = 1932 A3. Dcalc
(Z = 2) = 1.771 g cm�3. lMo = 11.1 cm�1; specimen:0.27 · 0.16 · 0.03; Tmin/max = 0.70. 2hmax = 50�;Nt = 21615, N = 9415 (Rint = 0.043), No = 2809;
R = 0.055, Rw = 0.051. |Dqmax| = 1.02(4) e A�3.
Variata. The fluorine atoms were modelled as disor-
dered over two sets of sites, occupancies set at 0.5 after
trial refinement.
2.4.1.2. 1:2 complexes. All data for these derivative ofCCD instrumentation, T ca. 153 K.
2.4.1.2.1. AgClO4:bpy (1:2). C20H16AgClN4O4,
M = 591.7. Monoclinic, space group P21/c,
a = 25.282(2) A, b = 7.1042(2) A, c = 24.911(2) A,
b = 118.714(2)�, V = 3924 A3. Dcalc (Z = 8) = 1.759 g
cm�3. lMo = 12.0 cm�1; specimen: 0.35 · 0.07 · 0.05
mm; Tmin/max = 0.61. 2hmax = 65�; Nt = 63562,
N = 14164 (Rint = 0.062), No = 8598; R = 0.042,Rw = 0.045. |Dqmax| = 1.29(8) e A�3.
Variata. (x,y,z,Uiso)H were refined.
2.4.1.2.2. AgClO4:phen (1:2). C24H16AgClN4O4,
M = 567.8.
(�a�). Triclinic, space group P�1, a = 6.9933(9) A,
b = 12.628(2) A, c = 24.734(3) A, a = 77.292(2)�,b = 83.665(2)�, c = 83.247(2)�, V = 2108 A3. Dcalc
(Z = 4) = 1.789 g cm�3. lMo = 11.3 cm�1; specimen:0.46 · 0.15 · 0.03 mm; Tmin/max = 0.90. 2hmax = 58�;Nt = 19210, N = 10062 (Rint = 0.026), No = 7756;
R = 0.041, Rw = 0.055. |Dqmax| = 0.79(7) e A�3.
(�b�). Monoclinic, space group P21/c, a = 7.0117(7) A,
b = 48.012(5) A, c = 12.647(1) A, b = 97.221(2)�,V = 4224 A3. Dcalc (Z = 8) = 1.785 g cm�3. lMo = 11.2
cm�1; specimen: 0.13 · 0.05 · 0.03 mm; Tmin/max =
0.76. 2hmax = 58�; Nt = 40883, N = 10604 (Rint = 0.070),No = 5824; R = 0.050, Rw = 0.049. |Dqmax| = 0.8(1) e
A�3.
Variata. In the triclinic form, perchlorate 2 was mod-
elled as disordered over a pair of sites, occupancies set at
0.5 after trial refinement. The monoclinic form was ob-
tained from acetonitrile solution.
2.4.1.2.3. Agtfs:bpy (1:2) ÆH2O (1:2:1). C21H18AgF3-
N4O3S, M = 587.3. Orthorhombic, space group Pna21ðC9
2; No: 33Þ, a = 36.968(3) A, b = 7.4185(7) A,
G.A. Bowmaker et al. / Inorganica Chimica Acta 358 (2005) 4371–4388 4375
c = 16.295(2) A, V = 4469 A3. Dcalc (Z = 8) = 1.746 g
cm�3. lMo = 10.6 cm�1; specimen: 0.15 · 0.10 · 0.07
mm; Tmin/max = 0.56. Nt = 87071, N = 6074 (Rint =
0.097), No = 4552; R = 0.064, Rw = 0.072; xabs = 0.45(7).
|Dqmax| = 1.9(1) e A�3. Crystallization solvent: ethanol/
acetonitrile.Variata. 2hmax was 58�. (x,y,z,Uiso)H were con-
strained at estimated values. Modelling of the structure
had its difficulties in respect of disorder and pseudo-
symmetry. �Friedel� pair data were preserved distinct.
tfs(2) was modelled as disordered over two sites, popula-
tions x = 0.674(9), 1 � x, each tfs being associated with
a residue modelled as a water molecule oxygen (no
hydrogens located), that associated with tfs(2) beingmodelled as disordered in concert.
2.4.1.2.4. Agtfs:phen (1:2). C25H16AgF3N4O3S,
M = 617.4. Monoclinic, space group C2/c
ðC62h; No: 15Þ, a = 26.687(1) A, b = 7.1408(3) A,
c = 26.068(1) A, b = 113.433(1)�, V = 4558 A3. Dcalc
(Z = 8) = 1.799 g cm�3. lMo = 10.4 cm�1; specimen:
0.14 · 0.11 · 0.09 mm; Tmin/max = 0.89. Nt = 44361,
N = 11579 (Rint = 0.033), No = 7369; R = 0.038,Rw = 0.044. |Dqmax| = 1.07(7) e A�3.
Variata. A room-temperature determination has been
recently reported [9] (x, y, z, Uiso)H were refined.
2.4.1.2.5. AgClO4:dmp (1:2) Æ 0.5EtOH. C29H27AgCl
N4O4.5, M = 646.9. Triclinic, space group P�1,a = 10.6186(6) A, b = 11.3411(6) A, c = 13.3675(8) A,
a = 64.897(1)�, b = 72.808(1)�, c = 69.895(1)�, V = 1347
A3. Dcalc (Z = 2) = 1.594 g cm�3. lMo = 8.9 cm�1; speci-men: 0.16 · 0.12 · 0.06 mm; Tmin/max = 0.84.
Nt = 28034, N = 10941 (Rint = 0.046), No = 6690;
R = 0.046, Rw = 0.045. |Dqmax| = 1.4(1) e A�3. Crystalli-
zation solvent: ethanol/pyridine.
Variata. Difference map residues were modelled as
ethanol of solvation, disordered about inversion centres.
Associated (x,y,z,Uiso)H were refined. Refinement is
presented in the same cell and coordinate setting as thatof [Ag(dmp)2](BF4). CH2Cl2 with which it is isomor-
phous [11].
2.4.1.2.6. AgNO3:dmp (1:2). C28H24AgN5O3, M =
586.4. Monoclinic, space group C2/c, a = 17.613(2) A,
b = 11.976(2) A, c = 12.329(2) A, b = 111.806(3)�,V = 2415 A3. Dcalc (Z = 4) = 1.613 g cm�3. lMo = 8.8
cm�1; specimen: 0.10 · 0.09 · 0.08 mm; Tmin/max =
0.60. Nt = 25054, N = 6355 (Rint = 0.052), No = 4453;R = 0.037, Rw = 0.038. |Dqmax| = 1.38(9) e A�3 (x, y, z,
Uiso)H were refined.
2.4.1.2.7. Agtfs:dmp (1:2). C29H24AgF3N4O2S,
M = 673.5. Monoclinic, space group P21/n,
a = 10.4753(7) A, b = 13.3829(9) A, c = 19.324(1) A,
b = 91.392(2)�, V = 2708 A3. Dcalc (Z = 4) = 1.651 g
cm�3. lMo = 8.8 cm�1; specimen: 0.18 · 0.14 · 0.08
mm; Tmin/max = 0.87. Nt = 52480, N = 13706 (Rint =0.037), No = 9108; R = 0.035, Rw = 0.036. |Dqmax| =
0.84(7) e A�3.
3. Results and discussion
As noted previously, a number of studies other than
structural have been recorded in the early literature for
adducts of the type Ag (oxyanion):L (1:1,2); as summa-
rized in (e.g.) Gmelin [22]: AgClO4:bpy (1:1), AgNO3:bpy (1:1), AgClO4:bpy (1:2), Agtfs:bpy (1:2), AgClO4:
dmp (1:2). The above/following arrays are presently
structurally characterized.
3.1. 1:1 complexes
Crystallization of silver(I) oxyanion salts AgX,
X = ClO4, NO3, tfa with the ligands bpy, bq and dpkin 1:1 stoichiometry from various solvents, mostly
found to be non-coordinating, has yielded a variety
of adducts of that stoichiometry, most being obtained
in bulk as well as crystalline, lending themselves to
characterization by elemental analysis, as well as
room-temperature single-crystal structure determina-
tion, the latter offering a basis for non-trivial vibra-
tional spectroscopy also. The complexes may beclassified in various dimensions: where the ligand,
appropriately disposed in cis-form, and the anion both
behave as discrete uni- or bi-dentate (chelate) donors,
mononuclear species may be found, in all cases taking
the aspect of a discrete molecular or ionic species, the
bite of the ligand necessarily resulting in N–Ag–N
being well below 180�, so that anion interaction in
some manner becomes inevitable unless displaced bya more strongly interacting solvent. Such is the case
with the previously studied 5,5 0- and 6,6 0-me2bpy/
NO3 arrays [15,16], also one of the forms found in
the structure of the dmp/NO3 complex [17]. (The other
is, unusually, binuclear [17], with MeCN displacing the
anion in the 5,5 0-me2bpy/ClO4 adduct [15].) With a
flexible ligand in trans-disposition, catenation of metal
atoms becomes possible and polymers may be ob-tained; these may also be consequent upon anion
bridging, where the basicity of the anion renders it suf-
ficiently interactive. The latter case is found in the
(pseudo-halide) bpy/SCN adduct [14], while the anion
is excluded or interacts peripherally with the silver in
the dpk/NO3, BF4 adducts [18,19]. These two types
predominate and we deal with the polymeric arrays
first, noting that, as might be expected, the parallelstacking of ligand ring systems is a dominant motif
in, and, presumably, a significant determinant of, crys-
tal packing throughout.
In AgClO4:bpy (1:1), we find a complex in which,
with a relatively weak donor oxyanion, the array takes
the form of a linear, one-dimensional polymeric cation,
made up of the silver and bpy moieties (Fig. 1(a)), and
essentially discrete anions, the latter contacting the sil-ver, Ag� � �O(1), at 2.92(1) A. One half of the formula
Fig. 1. Projections of the one-dimensional polymer arrays, normal to the polymer axes, for (a) AgClO4:bpy (1:1), (b) (i), (ii) AgClO4:dpk (1:1)
(strands 1,2), (c) AgNO3:bpy(1:1), and (d) AgNO3:bq (1:1).
4376 G.A. Bowmaker et al. / Inorganica Chimica Acta 358 (2005) 4371–4388
unit makes up the asymmetric unit of the structure;
silver, chlorine, and the mid-point of the bpy inter-ring
bond all lie disposed on crystallographic 2-axes. In the
anion Cl–O(1) is longer than Cl–O(2) (1.368(9), cf.
1.25(1) A) as might be expected, but the estimate of
the latter distance is undoubtedly affected by very high
�thermal motion�. O–Cl–O range between 102(1)� and
115.0(6)�, both about the symmetry axis, with other val-
ues intermediate (109.4(8)�, 110(1)�). The silver atom
has two nitrogen atoms to either side, the perturbation
of N–Ag–N (168.5(3)�) from linearity being associated
with the invasive but distant O(1)� � �Ag contact; Ag–N
Fig. 1 (continued )
G.A. Bowmaker et al. / Inorganica Chimica Acta 358 (2005) 4371–4388 4377
are 2.186(8) A, rather long by comparison with some of
the values found for linear N–Ag–N systems discussed
in an accompanying paper [1]. Interestingly, although
the two nitrogen atoms of the ligand span successive sil-ver atoms disposed helically up the 41-screw axis with
the spacing between being only 3.1780(5) A (almost
but not quite c/4, by virtue of the fact that the value
of x, corresponding to the Wyckoff special position
(x, 1/4 + x, 1/8) is not quite 3/4 (etc.) being 0.74734(4)),
this is achieved with the relative ring dispositions of
the bpy ligand being more nearly cis- than trans-, the
interplanar dihedral angle within the ligand being
43.1(4)�. At the nitrogen, Ag–N–C(2,6) are almost sym-
metrical (121.0(6)�, 119.0(7)�), as are C(2 0)–C(2)–N(1),
C(3) (118.3(8)�, 120.3(9)�), the dihedral angle betweenpairs of C5N planes trans about the silver atoms also
being 43.1(4)�.A preliminary comprehension of the structure of
AgBF4:dpk (1:1) [19] assists in understanding the struc-
ture of AgClO4:dpk (1:1) (Fig. 1(b); Table 1). In the
BF4� salt, one half of the formula unit comprises the
asymmetric unit of the structure. The silver atom is
Table 1
AgClO4:dpk (1:1): selected geometries
(Ligand/silver(n)) 1 2 3 Æ(ClO4)æ BF4
Bond distances (A)
Ag(n)–N(n11,m11) 2.21(1), 2.14(1) 2.19(1), 2.16(1) 2.20(1), 2.17(1) 2.18(2) 2.180(3)
Ag(n)–O(n21,m21) 2.59(1), 2.59(1) 2.57(1), 2.59(1) 2.56(1), 2.60(1) 2.58(1) 2.552(1)
Ag� � �Ag 4.938(1) 4.921(2) 4.925(2) 4.928(7) 4.858(1)
Bond angles (�)N(n1)–Ag(n)–O(n21) 69.1(5), 68.5(4) 68.2(4), 70.6(4) 69.9(4), 67.6(4) 69.0(10) 69.35(9)
N(n1)–Ag(n)–N(m1) 172.0(5) 177.2(4) 174.4(5) 175(2) 180(–)
N(n1)–Ag(n)–O(m21) 119.4(5), 102.9(4) 106.8(4), 114.3(4) 106.8(4), 115.6(4) 116(2)/105(2) 110.65(9)
O(n21)–Ag(n)–O(m21) 169.7(4) 173.5(3) 175.1(4) 173(2) 180(–)
Ag–O(n21)-Ag 144.4(5) 145.0(3) 146.3(4) 145.2(8) 144.3(1)
Ag–O(n21)–C(n21) 107.8(9), 107.6(9) 108.0(8), 106.9(8) 107.9(9), 104.8(9) 107(1) 107.85(7)
Ag–N(n1)–C(n2) 120(1), 123(1) 123(1), 124(1) 120(1), 119(1) 121(2) 120.8(2)
Intraligand dihedral angles (�) (two entries correspond to unprimed, primed sections)
AgNO/C5N 12.6(6) 11.8(7) 9.7(6) 11(1) 10.3(2)
C3O/C5N 28.2(8) 27.8(7), 27.8(2) 25.1(7), 30.0(7) 28(2) 27.2(2)
C5N/C5N 47.1(6) 50.1(6) 48.2(6) 49(1) 48.3(2)
C5N(n)/C5N(m) 3.7(6) 3.6(7) 2.9(6) 3.4(4) 0(–)
Out-of-plane deviations (A)
dAg/C5N 0.14(3) 0.16(3) 0.22(3) 0.17(3) 0.161(7)
dAg/C3O �1.32(3), 1.18(3) �1.28(3), 1.20(3)a �1.08(3), 1.43(3)a 1.3(1) (i) 1.214(6)
Values are intra ligand, for unprimed, primed sections, respectively, except where n, m are specified, these referring to atoms derivative of the next
ligand of the polymer.
For n = 1, read m = 1 0 (x, 1�y, 1/2 + z); for n = 2, m = 30; for n = 3, m = 20 (x,y, 1 + z). Values for the BF4� [19] salt are also included.
a Values for Ag(2,30 (x,y,z � 1)) (ligand 2), Ag(3,2) (ligand 3).
4378 G.A. Bowmaker et al. / Inorganica Chimica Acta 358 (2005) 4371–4388
disposed on a crystallographic inversion centre in space
group C2/c, the carbonyl group lying on a 2-axis, so that
the polymer is generated by an alternating succession of
these symmetry operations, propagating along c
(9.716(1) A) with two formula units within that dimen-
sion. The ligand thus functions as a bis(N,O-chelate),
the two chelate rings generated side-by-side within the
one ligand, the oxygen atom shared, mimicking an ex-
panded N,O/O,N version of the bis(chelating) O,O 0/
O 0,O00 nitrate group as in AgNO3:bq (1:1) below. The
pair of inversion-related pyridine ring planes coordi-
nated to the silver(I) are necessarily parallel, withN–Ag–N necessarily linear, this component of the array
dominating the coordination sphere in the familiar way,
with Ag–O long. Within the ligand, the two C5N planes
pivot about the C–O bond, in keeping with the crystal-
lographic 2-symmetry, diminishing H� � �H repulsions be-
tween the two rings. The present ClO4� structure is
essentially a perturbation/superlattice on the BF4� struc-
ture by a tripling of monoclinic b and modelled with adegradation in symmetry to a non-centrosymmetric
space group, three full formula units now comprising
the asymmetric unit of the structure, and being disposed
within two independent polymer strands. One strand,
disposed about (1/2,1/2,z), essentially replicates the pri-
mary strand containing the asymmetric unit of the BF4�
structure, but, devoid of symmetry within the single for-
mula unit, spans the c-dimension by generation of thesecond unit by the crystallographic glide. The second
and third formula units in succession span the c-dimen-
sion independently in the second polymer strand, dis-
posed in the vicinity of the previous symmetry related
strand of the BF4� structure about (1/2,3/4,z) (Fig.
1(b)). The two structures are sufficiently similar that
the perchlorate structure is essentially refinable using
the coordinates of the BF4� cell, but is improved, albeit
with some correlation evident, using all data, with the
present model. There is an appreciable difference in for-
mula volume between the two structures, determined at
similar temperatures, cell volume 1307 A3 for the BF4�
with counterpart 1341 (·3) A3 for the ClO4�, presum-
ably reflecting differences in anion volume, and evident
in expansion in the a and c dimensions. (Note:
b = 11.116(1) A (present b/3 = 11.155(2) A) (both at
room-temperature).) The c dimension, containing the
polymer strand, is increased in the perchlorate, leading
to an appreciably increased Ag� � �Ag distance
(4.928(3), cf. 4.858(1) A ðBF4�Þ). Probably, the most sig-
nificant change that we are entitled to read into the de-tail of the structure in association with this is to be
found in the silver environments of the perchlorate salt,
where considerable and presumably significant differ-
ences are found in the pairs of interligand N–Ag–O an-
gles, equivalent at 110.65(9)� in the BF4, with values
dispersed here to either side with disparities of 7–16�about the individual silver atoms. (It may be that in
the BF4 structure unresolved disorder or superlattice ef-fects, may result in differences of this type (but not of
Table 3
AgNO3:bq (1:1): the silver environment
Atom r N(10) O(1) O(2) O(2i) O(3i)
N(1) 2.339(1) 70.85(5) 113.07(5) 152.07(4) 102.14(5) 114.17(5)
N(1 0) 2.341(2) 140.25(5) 107.93(5) 118.77(5) 78.48(5)
O(1) 2.578(2) 49.44(5) 99.56(6) 127.05(6)
O(2) 2.747(2) 102.43(5) 92.21(5)
O(2i) 2.560(2) 48.11(5)
O(31) 2.727(2)
In the nitrate, N–O(1,2,3) are 1.255(2), 1.259(2), 1.236(2) A, opposed
angles being 120.0(2), 120.8(2), 119.2(2)�; Ag–O(1,2)–N are 103.8(1),
86.0(1)�; Ag–O(2i,3i)–N are 99.5(1), 92.0(1); Ag–O(2)–Agi is 172.15(7)�.Ag–N(1)–C(2,8a) (unprimed, primed sections) are 116.83(9), 123.6(1);
116.2(1), 122.2(1)�; N–C(2)–C(20)(unprimed,primed) are 117.0(1),
117.4(2)�. The dihedral angle between the two C9N planes is 7.41(4)�,dAg from the two planes being 0.148(2), 0.557(2) A. dAg, Agi from the
NO3 plane are �0.570(4), 0.148(2) A.
G.A. Bowmaker et al. / Inorganica Chimica Acta 358 (2005) 4371–4388 4379
this magnitude) being encompassed by the associated
�thermal envelopes�, but, on the evidence available, that
seems unlikely.) As noted in the description of the BF4�
structure, there is a considerable dihedral angle between
the pair of C5N rings within any one ligand, comparable
with that in AgClO4:bpy (1:1); as in the BF4� salt, how-
ever, the pair of rings about any one silver are disposed
with their nitrogen atoms quasi-trans and the associated
planes quasi-parallel, the structure behaving as if it were
a variant on AgClO4:bpy (1:1) with the inter-pyridine
bond expanded by insertion of the carbonyl entity,
and the repeat Ag� � �Ag distance expanding from
3.1780(5) to 4.928(7) (Æ æ) A in the process. Although,
acting as a constraint by bridging the silver atoms, albeitrather feebly, the interposition of the carbonyl group
may allow relaxation of the C5N ring dispositions about
the silver towards greater coplanarity, a tendency evi-
dent in bis(N-unidentate-py base) silver(I) arrays [1],
and perhaps encouraged by crystal packing dispositions.
The polymer strands here are more nearly twofold
rather than fourfold helices as in the bpy counterpart.
The above arrays provide examples wherein the poly-mer is generated by � � �AgLAgLAgL� � � arrays. An alter-
native form � � �AgXAgXAgX� � � is provided by
AgNO3:bpy (1:1), where the more basic nitrate anion is
now the entity active as bridging polymer generator, as
in the bpy/SCN adduct [14] and in contrast to the
dpk/NO3 adduct [18]. Here, one formula unit comprises
the asymmetric unit of the structure, the polymer being
generated by the 21 screw axis of monoclinic spacegroup P21/n. The bpy ligand now has the two cis rings
quasi-coplanar (interplanar dihedral angle 16.61(9)�)and coordinating as bidentate/chelate to the one silver
atom, the silver environment being completed by an
O,O 0-bidentate nitrate group, together with one of the
oxygen atoms bridging to the successive silver atom in
the cation polymer string (Fig. 1(c); Table 2). AgNO3:bq
(1:1) (Fig. 1(d); Table 3) has a more symmetricalarrangement of the nitrate group, chelating to either side
to successive silver atoms via O(1,2), O(2,3) (note the
Table 2
AgNO3:bpy (1:1):the silver environment
Atom r N(10) O(1) O(1i) O(2i)
N(1) 2.335(2) 70.84(6) 127.87(6) 118.93(6) 94.59(6)
N(1 0) 2.358(2) 133.54(6) 107.16(6) 142.43(6)
O(1) 2.362(2) 98.30(6) 83.01(6)
O(1i) 2.558(2) 49.03(5)
O(2i) 2.629(2)
The symmetry transformation i: 5/2 � x, y � 1/2, 1/2 � z.
In the nitrate, N–O(1,2,3) are 1.271(3), 1.242(3), 1.232(3) A, opposed
angles being 122.0(2)�, 120.0(2)�, 117.9(2)�; v2 (NO3 plane) is 16.3,
dAg, Agi being 0.087(4), 0.280(4) A. dAg from the C5N planes are
�0.096(4), 0.771(4) A. Ag–N(1)–C(2,6) (unprimed, primed rings) are
117.2(1)�, 124.2(2)�; 115.1(1)�, 124.2(2)�; N(1)–C(2)–C(20) (unprimed,
primed rings) are 117.0(2)�, 116.7(2)�. Ag–O(1)–N,Agi are 111.6(1)�,149.59(8)�, N–O(1)–Agi 97.7(1)�; Ag–O(2)–N 95.1(1)�.
comparison made with AgClO4:dpk (1:1) above) with
the silver environment more nearly representing atris(bidentate)/array; again the generator of the polymer
is the 21 screw axis of the P21/x cell, from the single for-
mula unit of the asymmetric unit. By contrast, in Ag-
NO3:dpk (1:1) [18], also with one formula unit in the
asymmetric unit, the generator of the polymer strand
is, again in P21/c, now the c glide. Here, a further form
is observed in which, although the bipyridyl ligand
bridges successive silver atoms in the polymer chain,the nitrate ion is invasive as a bidentate ligand, while
the dpk ligand is clearly partitioned into a unidentate-
N segment, and chelating O,N-segment, the dihedral an-
gle between the two C5N planes being ca. 61�, greaterthan found in the bis(O,N)-bidentate mode of Ag-
ClO4:dpk (1:1), and with the silver deviation from each
being ca. 0.25 A, respectively. The silver atom is essen-
tially coplanar with the nitrate plane; within the chelatering the C3O ketonic section is planar, dAg being ca. 1.5
A, the dihedral angle to the associated C5N plane being
ca. 33�. Despite the chelating nitrate and dpk ligand seg-
ment, the silver environment is again dominated by the
two nitrogen atoms, Ag–N being conspicuously shorter
than Ag–O, and with N–Ag–N 150.1(2)�.The rationale behind the formation of polymer versus
monomer form is unclear: polymers are found with all ofbpy, bq, dpk as ligands, the most basic tfa anion being
absent. Monomers, by contrast, are found with both
bpy and bq, involving both the least and most strongly
basic ClO4 and tfa anions. Two such species are found:
Agtfa:bpy (1:1) and AgClO4:bq (1:1), both evoking
appealing straightforward symmetrical forms, reminis-
cent of [NCAgL], L = phen, dmp recorded elsewhere re-
cently [3]. Agtfa:bpy (1:1), Fig. 2(a), comprises amolecule of the form [(bpy)Ag(O-tfa)] with a three-coor-
dinate array involving chelating cis-bpy and unidentate
O-tfa. Ag–N are similar 2.296(4), 2.325(5) A with Ag–
O (2.175(3) A) the shortest distance in the coordination
sphere; N–Ag–N is 71.5(2)� and O(1)–Ag–N(1,1 0) are
Fig. 2. Projections of the discrete mononuclear complexes, normal to their ligand �plane�, for (a) Agtfa:bpy (1:1), (b) AgClO4:bq (1:1) (i) (a projection
through the plane is also shown in (ii)), and (c) AgClO4:bq:MeCN (1:1:1), (d) AgClO4:bq:py (1:1:1), and (e) AgClO4:dmp:MeCN (1:1:1) (the cation).
4380 G.A. Bowmaker et al. / Inorganica Chimica Acta 358 (2005) 4371–4388
149.6(2)�, 138.2(2)�,P
(L–Ag–L) being 359.3� – a planar
environment, with the asymmetry in Ag–N and O–Ag–
N associated with distant incipient chelation via the ap-
proach of the second oxygen of the trifluoroacetate,
Ag� � �O 2.976(4) A. The dihedral angle between the
C5N planes is 10.0(2)�, dAg being �0.027(9), 0.537(9)A, their dihedrals to the C2O2 anion plane being 19.8�,24.6(2)�. The silver atom lies somewhat (0.091(1) A)
out of the ON2 coordination plane, the latter having
dihedral angles of 8.5(2)�, 10.0(2)� to the C5N planes
and 12.9(2)� to the C2O2 plane of the anion. By contrast,
AgClO4:bq (1:1) ” [(bq)Ag(O,O 0-ClO4)] involves four-
coordinate silver (Table 4; Fig. 2(b)), with Ag–N corre-
spondingly lengthened despite the diminished basicity ofthe anion cf. tfa and correspondingly longer Ag–O dis-
Table 4
AgClO4:bq (1:1): the silver(I) environment
Atom r N(1 0) O(1) O(2)
N(1) 2.310(3) 71.7(1) 140.5(1) 106.2(1)
N(1 0) 2.313(3) 108.1(1) 143.6(1)
O(1) 2.540(4) 49.8(1)
O(2) 2.880(5)
Ag–N–C(2,8a) (unprimed; primed sections) are 116.8(2)�, 123.5(2)�;116.5(2)�, 123.2(2)�; dAg (C9N (unprimed, primed)) are 0.284(5),
0.267(4) A; the dihedral angle between the two planes is 1.95(9)�.
tances. Ag–N in both are comparable to the values
found in three-coordinate [NCAgL] [3].
In contrast with copper(I) complexes of salts of sil-
ver(I) with acetonitrile are relatively rare, and it is of inter-
est in the present context to observe that, whereas for a
number of syntheses at various times, we have been ableto make use of acetonitrile as a convenient supporting
but non-coordinating solvent for obtaining adducts such
as those described in the present series of papers, its use in
the attempted synthesis of the present compound results
in displacement of the weak, potentially bidentate,
(O,O 0)-perchlorate donor in favour of the incorporation
of acetonitrile in the coordination sphere. In AgClO4:bq:
MeCN (1:1:1), one discrete aggregate comprising theasymmetric unit of the structure, we find the silver envi-
ronment reverting to an essentially three-coordinate array
(Fig. 2(c)), albeit with a long contact to a disordered oxy-
gen atom of the disordered perchlorate. Ag–N(bq) are
2.298(2), 2.273(2) A, N–Ag–N 72.60(6)�, cf. the counter-part values of 2.296(4), 2.325(5) A, 71.5(2)� in Agtfa:bpy
(1:1) (some asymmetry being noted above in the latter).
Ag–O in the latter is 2.175(3) A, quite short, in the circum-stances, but here, perhaps surprisingly in view of the
apparent reluctant coordination of acetonitrile to silver
more generally, Ag–N(CMe) is only 2.115(2) A,
(MeC)N–Ag–N(bq) being 136.65(8)�, 150.60(8)�, again
G.A. Bowmaker et al. / Inorganica Chimica Acta 358 (2005) 4371–4388 4381
a rather unsymmetrical array, but again, none the less,
planar,P
(N–Ag–N) being 359.7�. Ag–N–C(2,8a) are
116.6(1)�, 123.6(1)�; 116.9(1)�, 123.3(1)� for the unprimed
and primed ligand sections while N–C(2)–C(2 0,3) are
116.5(2)�, 122.0(2)�; 117.2(2)�, 120.8(2)�. The perchlorateapproach is at Ag–O 2.804(3) A. Ag–N–C(Me) is161.8(2)�, the pendant carbon atoms bent somewhat out
of the plane of the rest of the array; this planarity, as noted
above is prone to be relevant to crystal packing, and,
being somewhat extended throughout themolecule gener-
ally here, the result is entertaining (Fig. 3, showing this ar-
ray in company with themore obviously interesting of the
other arrays). While, apart from the 6,6 0-me2bpy/ClO4
adduct [16], this appears to be the only example of thistype of cation with silver(I), a number of counterparts
Fig. 3. Unit cell projections for (a) AgClO4:bpy (1:1), down c, showing the
(1:1:1), down b, (c) (i), (ii) AgClO4:dpk (1:1), down a, (d) AgClO4:dmp:MeC
with similar ligands are well-established for copper(I),
[LCu(NCMe)]+X� being structurally defined for
L = dmp (X = ClO4 [20], PF6 [20], BF4 [21]), wherein
Cu–N(L) range between 1.999(6) and 2.054(4) A (these
extremes in the one species) and Cu–N(C) (1.818(6) (out-
lier); 1.850(6)–1.856(2) A), a similar difference in bondlengths to that found in the present array. An interesting
counterpart species is defined in AgClO4:bq:py (1:1:1),
[(bq)Ag(py)(O2ClO2)] (asymmetric unit: one formula
unit, devoid of symmetry), in which Ag–N(bq) are
2.293(1), 2.336(1) A, Ag–N(py) 2.195(1) A interestingly
(seemingly less strongly bound than the MeCN) and
Ag–O (ordered ClO4) 2.826(1), 3.023(1) (Fig. 2(d)). The
AgN3 array is slightly pyramidal: N(py)–Ag–N(bq)147.79(5)�, 138.07(4)�; N(bq)–Ag–N(bq) 71.62(4)�,
helical cation columns interleaved with anions, (b) AgClO4:bq:MeCN
N (1:1:1) down c, and (e) AgNO3:bq (1:1), down c and a.
4382 G.A. Bowmaker et al. / Inorganica Chimica Acta 358 (2005) 4371–4388
P357.5�, the silver somewhat out of the N3 plane toward
the perchlorate. The dihedral angle between the pair of bq
aromatic planes is 11.01(3)�, with those to the C5N(py)
plane 36.23(5)�, 27.60(5)�. Syntheses of this type have
been previously recorded for AgClO4:phen:py (1:1:1)
and its dmp counterpart [22]. An array of similar type isalso found in AgClO4:dmp:MeCN (1:1:1) (Ag–N (dmp;
MeCN) 2.088(2), 2.243(1); 2.280(2) A; N(MeCN)–Ag–
N(dmp) 147.66(6)�, 137.36(6)�; N(dmp)–Ag–N(dmp)
74.35(5)�) (Fig. 2(e)). Here, however, the stacking of the
complex [(dmp)Ag(NCMe)]+ cations (Fig. 3(d)) pre-
cludes close interactions with the perchlorate anions and
there are noAg� � �Odistances<4 A. This latter compound
is similar to its previously studied copper(I)/ClO4, PF6,BF4 counterparts [20,21], in which (e.g., the BF4 salt)
the corresponding dimensions are 2.019(2), 2.034(2);
1.856(2) A; 140.79(7)�, 135.88(7)�; 83.17(6)�, the acetoni-
Fig. 4. Projection of Agtfa:dpk:dpk Æ H2O (2:1:2), (a) normal to, and
(b) down, the quasi-2-axis of the molecule and the unsolvated ligand
coordination �plane�, showing the anion approaches.
trile (relatively) more strongly bound, as might be
expected.
The final structurally characterized compound pre-
senting here as a �1:1 polymer� is also unusual. It is not
uncommon to find dipyridylketone occurring as its hy-
drate/hydrolysis product [(C5N)C(OH)2(C5N)], fromambiences where water is not rigorously excluded, so
that in the present context a compound such as the pres-
ent is not surprising although its nature is quite unex-
pected and novel. Agtfa:dpk:(dpk Æ H2O) (2:1:2) is a
discrete binuclear aggregate, one formula unit compris-
ing the asymmetric unit of the structure, as displayed in
Fig. 4. The central motif of the array is an Ag(dpk)Ag
moiety, the dpk bridging the pair of silver atoms byway of a shared central oxygen atom (as in the Ag-
ClO4:dpk (1:1) polymer described above), with one py
nitrogen to each silver atom completing its role as a pair
of shared chelates, the aggregate having 2 rather than m
symmetry by virtue of the twisting of the pair of py rings
about their OC Æ C bonds in avoidance of interaction of
the pair of hydrogen atoms at the 3-positions of the
rings. The dihedral angle between the two ring planesis 54.3(4)�, with the aforementioned H� � �H distance
ca. 2.4 A, at the van der Waals� limit. Ag–N, 2.210(8),
2.221(9) A, and Ag–O 2.714(9), 2.71(1) A, and associ-
ated angular geometries (Table 5), are generally quite
similar to their counterparts in the AgClO4:dpk (1:1)
Table 5
Agtfa:dpk:(dpk Æ H2O) (2:1:2): selected geometries
Atoms Parameter Atoms Parameter
Bond distances (A)
Ag(1)–N(11) 2.210(8) Ag(2)–N(11 0) 2.221(9)
Ag(1)–O(121) 2.714(9) Ag(2)–O(121) 2.71(1)
Ag(1)–N(21) 2.29(1) Ag(2)–N(31) 2.273(8)
Ag(1)–N(210) 2.393(8) Ag(2)–N(31 0) 2.43(1)
Ag(1)� � �Ag(2) 3.315(1) C(121)–O(121) 1.18(1)
Bond angles (�)O(121)–Ag(1)–N(11) 67.2(3) O(121)–Ag(2)–N(11 0) 66.9(3)
O(121)–Ag(1)–N(21) 88.7(3) O(121)–Ag(2)–N (31) 88.9(4)
O(121)–Ag(1)–N(21 0) 112.8(4) O(121)–Ag(2)–N((31 0) 106.7(4)
N(11)–Ag(1)–N(21) 154.7(4) N(11 0)–Ag(2)–N(31) 155.5(5)
N(11)–Ag(1)–N(21 0) 111.4(3) N(11 0)–Ag(2)–N(31 0) 106.6(3)
N(21)–Ag(1)–N(21 0) 84.3(3) N(31)–Ag(2)–N(310) 83.4(3)
Ag(1)–O(121)–Ag(2) 147.5(3)
Ag(1)–O(121)–C(121) 106.7(9) Ag(2)–O(121)–C(121) 105.2(8)
Ag(1)–N(11)–C(12) 123.6(9) Ag(2)–N(11 0)–C(12 0) 124.2(6)
Ag(1)–N(11)–C(16) 120.1(7) Ag(2)–N(11 0)–C(16 0) 120(1)
O(121)–C(121)–C(12) 121.1(9) O(121)–C(121)–C(12 0) 122(1)
C(12)–C(121)–C(12 0) 117.3(9)
N(11)–C(12)–C(121) 115.0(9) N(11 0)–C(12 0)–C(121) 113(1)
C(13)–C(12)–C(121) 121(1) C(13 0)–C(12 0)–C(121) 122(1)
Ag(1)–N(21)–C(22) 119.9(8) Ag(2)–N(31)–C(32) 119.0(7)
Ag(1)–N(21)–C(26) 120.8(6) Ag(2)–N(31)–C(36) 122(1)
Ag(1)–N(210)–C(22 0) 117.9(7) Ag(2)–N(31 0)–C(32 0) 117.3(8)
Ag(1)–N(210)–C(26 0) 123.7(7) Ag(2)–N(31 0)–C(36 0) 121(1)
C(221)–C(22)–N(21) 116(1) C(321)–C(32)–N(31) 116.3(9)
C(221)–C(22 0)–N(21 0) 116.1(9) C(321)–C(320)–N(31 0) 116(1)
C(22)–C(221)–C(22 0) 109(1) C(32)–C(321)–C(32 0) 107(1)
O(221)–C(221)–O(222) 110(1) O(321)–C(321)–O(322) 112(1)
G.A. Bowmaker et al. / Inorganica Chimica Acta 358 (2005) 4371–4388 4383
polymer; the silver atoms lie out of their associated C5N
planes by 0.19(2), 0.30(2) A. The remainder of the coor-
dination sphere of each silver atom is made up of a hy-
drated dpk ligand behaving as an N,N 0-bidentate,
achieved by folding at the central carbon, so that C5N/
C5N interplanar dihedral angles are 71.7(6)�, 74.3(6)�.The ligands are somewhat unsymmetrically coordinated:
Ag–N,N 0 2.29(1), 2.393(8); 2.273(8), 2.43(1) A, silver
atom deviations from the C5N planes being 0.47(2),
0.56(2); 0.61(2), 0.59(3) A; the overall disposition of
these ligands conforms to the overall good approxima-
tion to 2-symmetry of the total aggregate, the quasi-2-
axis being coincident with the with the central C–O
bond of the bridging dpk ligand. The N3 environmentof each silver deviates substantially from coplanarity
with it, the silver lying at the apex of the flat pyramid
(P
N–Ag–N) 350.5�, 345.5�) with the long bridging oxy-
gen approach occurring from within so that, despite the
apparent freedom of the hydrated dpk ligands, presum-
ably constrained otherwise by lattice forces, in adopting
an appropriate low energy disposition, the silver atoms
present an exceptionally naked aspect to the environ-ment beyond the cluster. Intriguingly, these do not inter-
act with the basic tfa counterions, which, rather,
Table 6
[AgL2]+ species: selected geometries.
L/X (/cation) r h /1
bpy/ClO4/1 2.241(4) 71.3(1) 100.9(1)
�2.434(2) 71.7(1) 125.2(1)
bpy/ClO4/2 2.279(3) 71.7(1) 103.0(1)
�2.383(3) 71,9(1) 120.9(1)
bpy/tfs/1 2.30(1) 71.5(4) 111.8(4)
�2.32(1) 71.3(4) 116.8(4)
bpy/tfs/2 2.30(1) 71.1(4) 107.6(4)
�2.34(1) 70.7(4) 122.2(4)
phen/ClO4/1 2.281(3) 72.5(1) 107.3(1)
ðP�1Þ �2.390(3) 71.9(1) 114.0(1)
phen/ClO4/2 2.273(3) 71.9(1) 110.1(1)
�2.426(3) 71.4(1) 111.1(1)
phen/ClO4/1 2.290(4) 71.9(1) 109.1(1)
(P21/c) �2.378(4) 71.6(1) 112.2(2)
phen/ClO4/2 2.267(4) 72.3(2) 107.1(1)
�2.416(4) 72.4(1) 113.7(2)
phen/tfs 2.319(2) 72.09(6) 109.68(6)
�2.358(1) 72.05(4) 113.38(6)
dmp/ClO4 2.247(2) 72.55(9) 106.3(1)
�2.413(2) 72.91(1) 122.23(7)
dmp/tfs 2.248(1) 73.06(4) 107.28(4)
�2.404(1) 72.45(4) 122.64(8)
dmp/NO3 2.304(1) 73.27(5) 115.61(5)
2.337(1) 125.92(5)
r/A are the Ag–N distances, h/� the N–Ag–N intraligand �bite� angles, /1/� theinterplanar dihedral angle between the pair of ligands, and f/� the interplanarare the silver deviations from the C5N rings (bpy) or the C12N2 planes (phe
approach the C(OH)2 moieties (O(11)� � �O(221)
(x � 1,y,z), O(12)� � �O(222) (x � 1,y,z), 2.63(1), 2.72(1)
A; O(21)� � �O(321) ð2� x; �y;�zÞ, 2.65(1), 2.781(1) A).
3.2. 1:2 complexes
The first adduct of the form Ag (oxyanion):L (1:2)
pertinent to the present array to be structurally charac-
terized was AgClO4:bpy (1:2) [5], typically an ionic com-
plex [AgL2]+(ClO4)
�. Other closely relevant complexes
subsequently defined have been enumerated above,
although the ramifications of arrays with related, ex-
tended and derivative ligands are widespread here, as
also for the 1:1 complexes. The present study defines ar-rays AgX:L (1:2) for bpy/ClO4 (a redetermination), bpy/
tfs (monohydrate), phen/ClO4 (two forms), phen/tfs (a
redetermination), dmp/NO3, dmp/ClO4 (an EtOH hem-
isolvate), dmp/tfs, all of the ionic form [AgL2]+X� (ÆS)
(Table 6; Figs. 5–7). Although it might be anticipated
that the combined effects of different anions in combina-
tion with ligands of diverse rigidity and hindrance, and
although diverse Ag–N distances are found, the diversi-ties within individual compounds can be as great as
those across the gamut of compounds studied, with little
/2 v f dAg
149.9(1) 26.37(5) 13.0(1) 0.290(6), 0.433(6)
158.1(1) – 15.6(2) 0.239(7), 0.592(7)
155.2(1) 18.01(6) 23.1(1) 0.718(6), 0.547(5)
159.9(1) – 22.2(1) 0.690(6), 0.466(6)
153.0(5) 41.5(2) 5.6(5) 0.25(2), 0.11(2)
156.8(5) – 3.7(6) 0.01(3), 0.16(3)
152.6(4) 41.0(2) 1.2(5) 0.04(2), 0.00(2)
154.9(4) – 3.3(5) 0.18(2), 0.07(2)
157.8(1) 29.37(5) 0.086(3)
165.7(1) 0.120(3)
170.1(1) 31.58(5) 0.125(3)
155.1(1) 0.108(3)
154.9(2) 32.85(7) 0.105(4)
169.3(2) 0.164(4)
155.7(2) 30.63(1) 0.122(4)
167.4(2) 0.098(4)
148.40(6) 40.97(3) 0.011(2)
167.38(6) 0.250(2)
139.5(1) 75.09(4) 0.001(2)
143.83(8) 0.512(2)
136.08(4) 76.68(2) 0.160(1)
147.02(4) 0.556(1)
140.57(5) 65.55(2) 0.086(1)
smaller and /2/� the larger pair of interligand N–Ag–N angles, v/� thedihedral angle between the two halves of the bipyridyl ligands. dAg/A
n, dmp).
4384 G.A. Bowmaker et al. / Inorganica Chimica Acta 358 (2005) 4371–4388
apparent difference between Ag–N(bpy) cf. (e.g.) Ag–
N(dmp). Similarly, it might be expected that such differ-
ences might impact on descriptors such as the deviation
of the silver atoms from their various ligand planes, and
indeed those excursions can be greater than 0.7 A, but
one of the smallest divergences observed is found inthe dmp/NO3 adduct, in the context of a highly hindered
ligand (dmp).
It is of interest that most of the complexes of the lat-
ter ligand crystallize with one formula unit (or less) in
the asymmetric unit; within the cations of the three
dmp complexes, the interplanar dihedral angles between
the pair of ligand planes are much closer to orthogonal-
Fig. 5. (a) Unit cell contents of [Ag(dmp)2](NO3), projected down b. (b) Pro
planes.
ity (>65�) than is the case with the adducts of the unhin-
dered bpy, phen ligands. The interactions between
cations of the type ML3, L = bpy, phen, have been ana-
lysed previously in terms of �embraces� [23]; among the
present three dmp complexes in two (ClO4, tfs), we find
centrosymmetrically related pairs of cations with non-coplanar ligands but not disposed in a manner evocative
of that term (Figs. 5 and 6); in the NO3 complex, which
displays the smallest interplanar dihedral angle between
the two ligands, the lattice array is more suggestive of
one dominated by stacking interactions. The latter obvi-
ously dominate in the arrays of the adducts of bpy,
phen, the archetype of which is the pseudo-symmetric
jection of the cell down a*, showing the mutually �orthogonal� sets of
Fig. 6. Unit cell contents of [Ag(dmp)2](tfs) (also representative of the
perchlorate), projected down a.
Fig. 7. (a) Unit cell contents, projected down the short cell axes, for the AgX
(iii, iv) phen/ClO4 (triclinic and monoclinic forms). (b) Projection of [Ag(bp
[Ag(phen)2]ClO4 (triclinic form), as representative.
G.A. Bowmaker et al. / Inorganica Chimica Acta 358 (2005) 4371–4388 4385
array found in the bpy/tfs adduct (Fig. 7), shown in pro-
jection in an orthogonal cell, with Ag� � �Ag 3.613(2),
3.831(2) A, and comprising columns of cations, the li-
gands obliquely inclined to b interspersed by anion/sol-
vent arrays, Ag(1) and Ag(2) alternating in the stack.
b is ca. 7 A, corresponding to two successive cations;similar stacks of cations interspersed by columns of an-
ions (and solvent) in the other adducts described (bpy/
ClO4; phen/ClO4 (two phases), tfs), all disposed up axes
approximately 7 A in length. In the bpy/ClO4 adduct the
two cations of the asymmetric unit define distinct col-
umns, Ag(1)� � �Ag(1) spacings being 3.7764(5) A, while
Ag(2)� � �Ag(2) are 3.6512(5) A (Fig. 7). In the phen/tfs
adduct, Ag� � �Ag are 3.9505(3) A, there being one silverin the asymmetric unit. The phen/ClO4 adduct is
remarkable, being defined in two polymorphs: triclinic
and monoclinic. In both forms, the two independent cat-
ions of the asymmetric unit alternate in the stacks, spac-
ings being 3.5493(6), 3.7640(6) A in the triclinic form,
and 3.7168(6), 3.6460(8) A in the monoclinic. If the
:L (L 6¼ dmp) (1:2) arrays ([AgL2]X) for L/X = (i, ii) bpy/ClO4, tfs, and
y)2](tfs) ÆH2O down c (section about z = 0.5). (c) The cation stack of
Fig. 7 (continued)
4386 G.A. Bowmaker et al. / Inorganica Chimica Acta 358 (2005) 4371–4388
columns are considered as envelopes of rectangular
cross-section, the long axes of the cross-section lie
parallel in the bpy,phen/tfs and phen/ClO4 (triclinic)
forms, but occupy sheets of alternating direction in the
bpy,phen/ClO4 adducts.
In these latter structures, the most striking feature is
the almost square-planar coordination environment of
the silver, which in the absence of any electronic imper-ative ascribable to the metal must be considered conse-
quent upon the stacking attributes arising from the
ligand arrays.
3.3. Vibrational spectra of the 1:1 complexes
In a previous paper, we assigned bands in the far-IR
spectra of complexes [L2AgY] (L = py or substituted pybase; Y = ClO4, NO3, tfa) due to the symmetric and
antisymmetric m(AgN) modes, ms and ma, respectively,
of the N–Ag–N units in these complexes. It was also
shown that the wavenumbers of these bands correlate
well with the trend in Ag–N bond lengths, the shorter
Ag–N giving rise to higher m(AgN) values [1]. We have
therefore recorded the far-IR spectra of the compounds
described in the present study to examine whether simi-lar relationships exist for these, and whether the different
structural types revealed in the crystallographic study
might be distinguished on the basis of their vibrational
spectra. However, a complicating factor is that the
low-wavenumber vibrational spectra of the ligands in-
volved in the present study contain strong bands in the
region below 200 cm�1, where the m(AgN) bands are ex-
pected to occur. Of the compounds characterized here,
the two AgClO4/bq compounds offered the best startingpoint for an analysis, since these have closely similar
structures, which differ only in the presence of a MeCN
ligand. The far-IR spectra of AgClO4:bq (1:1), Ag-
ClO4:bq:MeCN (1:1:1), and of the uncomplexed bq li-
gand are shown in Fig. 8. One readily apparent feature
in the spectra of the two complexes is the strong band
at about 620 cm�1 due to the m4 mode (T2 symmetry)
of the ClO4� ion. This band shows a splitting into two
components at 622, 614 cm�1 in AgClO4:bq (1:1), but
this splitting is absent in the spectrum of the MeCN
complex. The splitting is due to a lowering of the sym-
metry of the ClO4� ion as it interacts with the silver
atom, and the loss of this splitting in the MeCN complex
is consistent with the greater Ag–O distances (2.78(2),
2.99(3) A) compared with that in the parent complex
(2.540(4) A). Most of the remaining bands in the spectracan readily be correlated with those of the uncomplexed
Wavenumber/cm-1100200300400500600700
Abs
orba
nce
(a)
(b)
(c)
622
614
620
156
113
151 11
711
310
0
Fig. 8. Far-IR spectra of: (a) AgClO4:bq (1:1), (b) AgClO4:bq:MeCN
(1:1:1), and (c) the uncomplexed bq ligand.
G.A. Bowmaker et al. / Inorganica Chimica Acta 358 (2005) 4371–4388 4387
ligand, indicating that these can be assigned to the coor-
dinated ligand. On the basis of the Ag–N bond lengths
and the correlation established for pyridine and substi-
tuted pyridine complexes [1], the m(AgN) bands are ex-
pected to occur in the region 100–140 cm�1. Bands atabout 155, 115 cm�1 are thus in the right position to
be assigned as m(AgN), but the presence of ligand bands
at 113, 100 cm�1 render these assignments uncertain.
The situation is similar for the other bq complexes,
and for the bpy complexes. Uncomplexed bpy has sev-
eral bands in the 100–200 cm�1 region, and this pre-
cludes any definite m(AgN) assignments for the silver
complexes. Uncomplexed dpk, on the other hand, is rel-atively clear of bands in the 100–200 cm�1 region, and
this allows the tentative assignment of m(AgN) bands
in the perchlorate at 156, 121 cm�1, and in the nitrate
at 168, 138 cm�1.
4. Conclusion
Systematic extension of sporadic individual studies of
1:1 adducts of common important N,N 0-bidentate li-
gands derivative of 2,2 0-bipyridyl, and, like it, flexible
in regard to rotation about the interring bond (2,2 0-
biquinolyl, 2,2 0-dipyridyl-ketone) with silver(I) oxyan-
ion salts AgX of increasing anion basicity: ClO4, NO3,
F3CCO2, has resulted, in a number of cases, in the iso-
lation of one-dimensional polymers, wherein the pair
of N-base functionalities of the ligand bond to different
silver atoms, catenating them; with the more basic oxya-
nions, the anion may behave as the catenating entity, the
ligand chelating, or it also may coordinate or chelate so
that mononuclear [LAgX] results. Interesting latticedispositions derivative of overlap of the planar ligand
components are pervasive among the array, a fortiori
among the AgX:L (1:2) adducts where, except for com-
plexes of the hindered dmp ligand, novel quasi-planar
four-coordinate cations consequent on their stacking,
dominate.
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