Novel solvates in AgX:dpex (n:1) systems (n = 1 or 2); X = oxyanion; dppx = Ph2P(Y)PPh2, Y = (CH2)3, Fc

Article abstract of DOI:10.1016/j.ica.2005.12.015

Novel solvated forms are spectroscopically (¹H, ¹³C, ³¹P, IR and conductivity studies) and structurally described for diverse silver oxyanion salt:bis(diphenylphosphino)-ligand adducts of 2:1:n (AgX:dppx:S) stoichiometry. AgClO₄:dppf:MeCN (2:1:4) ('dppf' = bis(diphenylphosphino)ferrocene) is a binuclear centrosymmetric species: [(O₃ClO)(MeCN)₂Ag(P-dppf-P′)Ag(NCMe)₂(OClO₃)], Ag-P short at 2.368(1) ?. Two MeOH/H₂O solvates are described, of AgX:dppp (2:1) stoichiometry, both single stranded polymers (X = carboxylate: 'ac' = acetate, 'tfa' = trifluoroacetate; 'dppp' = Ph₂P(CH₂)_xPPh₂; x = 3), with silver atoms spanned alternately by: (i) a P-dppp-P′ bridge, supported by tenuously bridging water or methanol, and (ii) O-ac, tfa-O′ bridge(s), being assigned stoichiometries Agtfa:dppp:H₂O (2:1:1) · MeOH and Agac : dppp : MeOH ( 2 : 1 : 0.5 ) · 3 frac(1, 2) H₂ O. The structure of AgClO₄:dppe:MeCN (1:1:1) ('dppe', x = 2), also a one-dimensional polymer, but with all Ag...Ag sequences bridged by the P,P′ ligand, and with unidentate MeCN and OClO₃ coordinated to the silver, is also recorded.

Full text of DOI:10.1016/j.ica.2005.12.015

Inorganica Chimica Acta 359 (2006) 2170–2177
www.elsevier.com/locate/ica
Novel solvates in AgX:dpex (n:1) systems (n=1 or 2); X=oxyanion;
dppx=Ph2P(Y)PPh2, Y=(CH2)3, Fc
a
a,
b
b
Augusto Cingolani , Effendy b,c, Claudio Pettinari *, Brian W. Skelton , Allan H. White
a
`
Dipartimento di Scienze Chimiche, Universita degli Studi di Camerino, Via S. Agostino 1, 62032 Camerino MC, Italy
Chemistry M313, School of Biomedical, Biomolecular and Chemical Sciences, University of Western Australia, Crawley, WA 6009, Australia
b
c
Jurusan Kimia, FMIPA Universitas Negeri Malang, Jalan Surabaya 6, Malang 65145, Indonesia
Received 2 November 2005; accepted 11 December 2005
Available online 8 February 2006
Abstract
Novel solvated forms are spectroscopically (1H, 13C, 31P, IR and conductivity studies) and structurally described for diverse silver
oxyanion salt:bis(diphenylphosphino)-ligand adducts of 2:1:n (AgX:dppx:S) stoichiometry. AgClO4:dppf:MeCN (2:1:4) (‘dppf’ =
bis(diphenylphosphino)ferrocene) is a binuclear centrosymmetric species: [(O3ClO)(MeCN)2Ag(P-dppf-P0)Ag(NCMe)2(OClO3)], Ag–P
˚
short at 2.368(1) A. Two MeOH/H2O solvates are described, of AgX:dppp (2:1) stoichiometry, both single stranded polymers (X =
carboxylate: ‘ac’ = acetate, ‘tfa’ = trifluoroacetate; ‘dppp’ = Ph2P(CH2)xPPh2; x = 3), with silver atoms spanned alternately by: (i) a
P-dppp-P0 bridge, supported by tenuously bridging water or methanol, and (ii) O-ac, tfa-O0 bridge(s), being assigned stoichiometries
Agtfa:dppp:H2O (2:1:1) Æ MeOH and Agac:dppp:MeOHð2:1:0:5Þ ꢀ 3 12 H2O. The structure of AgClO4:dppe:MeCN (1:1:1) (‘dppe’,
x = 2), also a one-dimensional polymer, but with all Ag. . .Ag sequences bridged by the P,P0 ligand, and with unidentate MeCN and
OClO3 coordinated to the silver, is also recorded.
ꢀ 2005 Elsevier B.V. All rights reserved.
Keywords: Silver; Diphosphine; Solvate silver complexes; X-ray; NMR spectroscopy; Polynuclear complexes
1. Introduction
acetonitrile, namely AgClO4:dppf:MeCN (2:1:4) (‘dppf’ =
bis(diphenylphosphino)ferrocene), while with the silver(I)
carboxylates Agac, Agtfa ð‘ac’ ¼ CH3CO2ꢁ; tfa ¼ CF3-
CO2ꢁÞ, a pair of novel one-dimensional polymers obtained
from (aqueous) methanol are described. An adduct of 1:1
AgClO4:dppe stoichiometry also forms a solvated polymer:
AgClO4:dppe:MeCN (1:1:1).
As noted in the preceding paper [1], the formation of
adducts of MX:dpex (2:1) stoichiometry (M = Cu(I),
Ag(I); X = simple anion; dpex = Ph2E(CH2)xEPh2, E =
P, As(, Sb)) results in the possibility of situations where
coordinative unsaturation may arise in consequence of
the dearth of ligand donor atoms, particularly so where
the anion is a weak donor, leading to the possibility
of coordination by solvent molecules. With Cu(I), acetoni-
trile is a particularly potent donor solvent, and we have
described the structural characterisation of a number of
diverse solvates of such complexes. With Ag(I) analogues,
acetonitrile is a less effective donor; in the present paper
we describe a few solvates that we have obtained in such
circumstances, only one of 2:1 stoichiometry being with
2. Experimental
All syntheses and handling were carried out in the air.
All chemicals were purchased from Aldrich and Lancaster
and used without further purification. Elemental analyses
(C, H, N) were performed in house with a Fisons Instru-
ments 1108 CHNS-O Elemental Analyser. IR spectra were
recorded from 4000 to 100 cmꢁ1 with a Perkin–Elmer
1
System 2000 FT-IR instrument. H, 13C and 31P NMR
*
spectra were recorded on a Mercury Plus Varian 400
Corresponding author. Tel.: +39 0737 402234; fax: +39 0737 637345.
E-mail address: claudio.pettinari@unicam.it (C. Pettinari).
1
NMR spectrometer (400 MHz for H, 100 MHz for 13C,
0020-1693/$ - see front matter ꢀ 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2005.12.015

A. Cingolani et al. / Inorganica Chimica Acta 359 (2006) 2170–2177
2171
and 162.1 MHz for 31P). H and C chemical shifts are
reported in ppm versus SiMe4, P chemical shifts in ppm
versus H3PO4 85%. The electrical conductances of the ace-
tone, dichloromethane, DMSO and acetonitrile solutions
were measured with a Crison CDTM 522 conductimeter
at room temperature.
which was filtered off and shown to be compound 3
(0.790 g, yield 70%); a few more substantial crystals were
obtained from the mother liquor on standing. M.p. 94–
96 ꢁC dec. Anal. Calc. for C42H40Ag2Cl2FeN4O8P2: C,
44.51; H, 3.56; N, 4.94. Found: C, 44.35; H, 3.76; N,
5.11%. IR (nujol, cmꢁ1): 2310w m(CN), 1090sbr, 621s
m(ClO4), 541m, 520m, 513m, 485m, 487m, 450br sh,
1
2.1. Syntheses
420w, 399w, 303w, 280m. H NMR (CD3CN, 293 K): d,
2.22 (s, 12H, CH3MeCN), 4.15 (s, 4H, C5H4Fc), 4.56 (s,
4H, C5H4Fc), 7.5br (s, 20H, C6H5Fc). 13C NMR (CD3CN,
293 K): d, 74.96, 75.32, 75.40, 130.0 (m, C6H5dppf), 131.88
(s, C6H5dppf), 134.13 (m, C6H5dppf). 31P NMR (CD3CN,
293 K): d, 0.1br. 31P NMR (CD3CN, 233 K): d, 1.0 (dd,
Safety note: Perchlorate salts of metal complexes with
organic ligands are potentially explosive! Only small
amounts of materials should be prepared, and these should
be handled with great caution.
1
1J(31P–109Ag): 730 Hz, J(31P–107Ag): 633 Hz).
2.1.1. Agtfa:dppp:H2O (2:1:1)ÆMeOH (1)
Agtfa (0.440 g, 2.0 mmol) was added to a methanol solu-
tion (10 mL) containing dppp (0.412 g, 1 mmol). A color-
less precipitate immediately formed. The suspension was
stirred overnight, then was filtered off and the colorless res-
idue washed with a methanol:diethyl ether mixture (1:1)
and shown to be compound 1 (0.497 g, yield 55%); a few
more substantial crystals were obtained from the mother
liquor on standing. M.p. 160 ꢁC dec. Anal. Calc. for
C32H32Ag2F6O6P2: C, 42.50; H, 3.57. Found: C, 42.57;
H, 3.56%. IR (nujol, cmꢁ1): 3300br m(OH), 1667s, 1651s,
1436s m(CO), 1196s, 1137m, 1099s, 516m, 480m, 459w,
2.1.4. AgClO4:dppe:MeCN (1:1:1) (4)
AgClO4 (0.41 g, 2.0 mmol) was added to an acetonitrile
solution (10 mL) containing dppe (0.80 g, 2.0 mmol). The
clear pale-yellow solution was stirred overnight, then evap-
orated under vacuum until a pale-yellow precipitate formed
which was filtered off and shown to be compound 4 (0.64 g,
yield 50%); a few more substantial crystals were obtained
from the mother liquor on standing. M.p. 163–165 ꢁC.
Anal. Calc. for C28H27AgClNO4P2: C, 52.00; H, 4.21; N,
2.17. Found: C, 51.95; H, 4.36; N, 2.11%. IR (nujol,
cmꢁ1): 2310w m(CN), 1099sbr, 620s m(ClO4), 507m, 480m,
421w, 400w, 30w, 345w, 320w, 280w, 255w. 1H NMR
(CD3CN, 293 K): d, 2.19 (s, 3H, CH3MeCN), 2.45 (s, 4H,
CH2dppe), 7.5 (br, 20H, C6H5dpp). 13C NMR (CD3CN,
293 K): d, 24.82 (s, CH2dppe), 130.71, 132.46, 134.04 (br,
C6H5dppe). 31P NMR (CD3CN, 293 K): d, 6.1br. 31P
1
423w, 270w. H NMR (CD3CN, 293 K): d, 1.8 (m, 2H,
CH2dppp), 2.22 (br, 2H, H2O), 2.47 (q, 4H, CH2dppp), 3.35
(s, 3H, CH3OH), 7.5 (m, 12H, C6H5dppp), 7.6 (pt, 8H,
C6H5dppp). 13C NMR (CD3CN, 293 K): d, 23.5 (m,
CH2dppp), 28.20 (s, CH2dppp), 28.5 (s, CH2dppp), 130.2 (d,
Cdppp), 132.0 (s, Cdppp), 133.9 (d, Cdppp), 207.56 (s, CO).
31P NMR (CD3CN, 293 K): d, 8.0br. 31P NMR (CD3CN,
1
NMR (CD3CN, 233 K): d, 6.88 (d, J(31P–Ag): 460 Hz),
1
5.6 (d, J(31P–Ag): 502 Hz).
1
233 K): d, 7.8 (d br, J(31P–Ag): 705 Hz).
2.2. Structure determinations
2.1.2. Agac:dppp:MeOH(2:1:0:5) ꢀ 3 12 H2O (2)
Compound 2 has been prepared in 70% yield (0.576 g)
following a procedure similar to that reported for 1 by
using Agac (0.334 g, 2.0 mmol) and dppp (0.412 g,
1.0 mmol). M.p. 118–120 ꢁC. Anal. Calc. for C31.5H41Ag2-
O8P2: C, 45.84; H, 5.01. Found: C, 45.67; H, 4.86%. IR
(nujol, cmꢁ1): 3300br m(OH), 1560s, 1375 shsh br m(CO),
General procedures are described in the preceding paper
[1]; specific details are as follows. CCDC 286292–286295.
2.2.1. Agtfa:dppp:H2O (2:1:1)ÆMeOH,
1 ” C32H32Ag2F6O6P2, M = 904.3
Monoclinic, space group Pn (C52, No. 7 (variant)), a =
1
˚
1100m, 516m, 483m, 459w, 414w, 324w, 279w. H NMR
12.845(2), b = 7.978(1), c = 17.002(2) A, b = 101.547(2)ꢁ,
3
˚
(CD3CN, 293 K): d, 1.85 (m, 2H, CH2dppp), 1.9 (br, 2H,
H2O), 2.47 (q, 4H, CH2dppp), 3.35 (s, 3H, CH3OH), 4.8
(OH), 7.5 (m, 12H, C6H5dppp), 7.6 (pt, 8H, C6H5dppp).
13C NMR (CD3CN, 293 K): d, 23.5 (m, CH2dppp), 28.20
(s, CH2dppp), 28.5 (s, CH2dppp), 130.2 (d, Cdppp), 132.0 (s,
Cdppp), 133.9 (d, Cdppp), 207.56 (s, CO). 31P NMR
(CD3CN, 293 K): d, 8.5br. 31P NMR (CD3CN, 233 K): d,
V = 1708 A . Dc (Z = 2) = 1.758 g cmꢁ3. lMo = 13.2 cmꢁ1
;
=
specimen: 0.73 · 0.15 · 0.12 mm; ‘T’min/max = 0.65. 2hmax
58ꢁ; Nt = 15276, N = 3931 (Rint = 0.047), No = 3636;
R = 0.056, Rw = 0.074. CCD instrument, T ca. 153 K.
Variata: Methanol hydrogen atoms were not located.
2.2.2. Agac:dppp:MeOH(2:1:0:5) ꢀ 3 12 H2O;
2 ꢂ C31:5H41Ag2O8P2
1
1
7.96 (dd, J(31P–109Ag)): 759 Hz, J(31P–107Ag): 664 Hz.
Monoclinic, space group P21/n (C52h, No.14), a =
˚
2.1.3. AgClO4:dppf:MeCN (2:1:4) (3)
8.042(2), b = 19.245(4), c = 22.136(4) A, b = 91.660(5)ꢁ,
3
˚
AgClO4 (0.41 g, 2.0 mmol) was added to an acetonitrile
solution (10 mL) containing dppf (0.53 g, 1 mmol). The
clear pale-yellow solution was stirred overnight, then evap-
orated under vacuum until a pale-yellow precipitate formed
V = 3425 A . Dc (Z = 4) = 1.601 g cmꢁ3. lMo = 12.8 cmꢁ1
;
=
specimen: 0.15 · 0.10 · 0.08 mm; ‘T’min/max = 0.54. 2hmax
58ꢁ; Nt = 48607, N = 9076 (Rint = 0.097), No = 5794; R =
0.063, Rw = 0.073. CCD instrument, T ca. 153 K.

2172
A. Cingolani et al. / Inorganica Chimica Acta 359 (2006) 2170–2177
3
˚
Variata: One of the two independent acetate groups in
c = 105.99(3)ꢁ, V = 1431 A . Dc (Z = 2) = 1.501 g cmꢁ3
.
=
the structure is modelled as disordered over two sets of
sites, occupancies set at 0.5 after trial refinement; it bridges
a pair of silver atoms, one of which is coordinated by the
methanol group, whose occupancy refines also to ca. 0.5,
(at which value it was constrained), occupancy perhaps in
concert with one of the acetate orientations; the associated
OH hydrogen atom was not located. Other difference map
residues were modelled as water molecule oxygen atoms
(hydrogens not located), with large displacement parame-
ters but seemingly of total occupancy in refinement.
l
Mo = 9.4 cmꢁ1; specimen: 0.38 · 0.20 · 0.18 mm; Tmin,max
0.72, 0.84. 2hmax = 50ꢁ; N = 5010, No = 3436; R = 0.048,
Rw = 0.050. Single counter instrument, T ca. 295 K.
3. Results and discussion
3.1. Syntheses
The reaction of two equivalents of AgX (X = ac or tfa)
with one equivalent of 1,3-bis(diphenylphosphino)propane
(dppp) at room temperature in methanol gave rise to the
compounds Agtfa:dppp:H2O (2:1:1) Æ MeOH (1) and
2.2.3. AgClO4:dppf:MeCN (2:1:4),
3 ” C42H40Ag2Cl2Fe-N4O8P2, M=1133.3
Agac:dppp:MeOH (2:1:0.5) ꢀ 3 12 H2O (2),
respectively
Monoclinic, space group P21/c (C52h, No.14), a =
(Chart 1). The choice of solvent and the ligand to metal
ratio are both determinants in the formation of the com-
pounds. For example, when both reactants were mixed
and stirred in a 1:1 ligand to metal molar ratio, the well-
known 1:1 adducts have been obtained. A strict 1:2 ligand
to metal ratio is required in order to prevent formation of
1:1 [2] or 2:1 adducts. The adduct AgClO4:dppf:MeCN
(2:1:4) (3) (Chart 2) has been obtained with limited crys-
talline components from the slow evaporation of the
mother liquor of an MeCN solution containing the metal
salt and dppf in 2:1 molar ratio.
˚
10.528(3), b = 25.979(6), c = 8.565(3) A, b = 91.39(2)ꢁ,
3
V = 2342 A . Dc (Z = 2) = 1.607 g cmꢁ3. lMo = 13.7 cmꢁ1
;
˚
specimen: 0.42 · 0.30 · 0.62 mm; Tmin,max = 0.58, 0.71.
2hmax = 50ꢁ; N = 4112, No = 2555; R = 0.040, Rw =
0.041. Single counter instrument, T ca. 295 K.
Variata: Disorder was resolvable in two of the perchlo-
rate oxygen atoms, one of them coordinated, and in one of
the acetonitrile groups coordinated to the same silver atom,
presumably concerted; site occupancies of the disordered
components were set at 0.5 after trial refinement.
The compound AgClO4:dppe:MeCN (1:1:1) (4) (Chart
3) has been obtained only when a 1:1 ligand to metal ratio
has been employed. When a ligand excess was employed,
the previously reported 2:1 species formed [3], whereas
when a metal excess was used, only intractable material
2.2.4. AgClO4:dppe:MeCN (1:1:1), 4 ” C28H27AgClNO4P2,
M=646.8
1
ꢀ
˚
Triclinic, space group P1 (Ci , No. 2), a = 13.450(2), b =
11.278(6), c = 10.118(2) A, a = 100.52(4), b = 96.12(2),
O
O
Ph
Ph
Ph
Ph
C
CF3
C
CH3
P
P
Ag
OH2
O
P
P
Ag
O
H O CH3
Ag
Ag
O
O
O
O
O
O
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ag
CF3
CF3
CH3
CH3
O
O
O
P
Ag
P
OH2
Ag
H O CH3
P
P
Ag
Ph
O
O
Ph
Ph
Ph
C
CF3
C
CH3
O
O
2
1
Chart 1.

A. Cingolani et al. / Inorganica Chimica Acta 359 (2006) 2170–2177
2173
unidentate, chelating bidentate or bridging bidentate
groups on the basis of D values (where D = ma(COO)–
ms(COO)), the trend generally accepted being:
OClO3
Ph
Ph
NCCH3
P
Ag
NCCH3
NCCH3
Fe
Dunidentate > Dionic > Dbridging bidentate > Dchelating bidentate
In compounds 1 and 2 the D is ca. 180 cmꢁ1, respectively, in
accordance with unsymmetrical bidentate coordination of
the carboxylate group, and consistent with the X-ray data.
P
Ag
NCCH3
Ph
Ph
OClO3
ꢁ
3
In the case of ionic ClO4 Td geometry only two vibra-
tions (m3 and m4) are expected to be IR active [8], as in fact is
found in 3 and 4, at ca. 1100 and 620 cmꢁ1, in good accor-
Chart 2.
dance with the results found in the solid state that suggest
ꢁ
the existence of a weak perturbation of ClO4
.
Ph
Ph
Solution studies, being unlikely to reflect, in detail or
more generally, the complexed polymeric forms present
in the solid, should be considered with that caveat in mind.
P
P
Ag
1
In the H NMR spectra of 1–4 in CD3CN (Section 2), the
NCCH3
Ph
Ph
signals due to the diphosphine exhibit a different pattern
relative to those found for the free donors, confirming
the occurrence at least of partial complexation in solution.
The bridging methylene resonances in 1, 2 and 4, appear as
broad singlets or resolved multiplets generally between 1.00
and 2.50 ppm downfield shifted with respect to those found
in the free donors.
Ag
P
OClO3
OClO3
Ph
Ph
Ph
Ph
P
P
P
Ag
31P chemical shifts (CDCl3 solution) and 31P–Ag cou-
pling-constants for all derivatives are reported in Section
2. Our experiments have been carried out at a concentra-
tion of 0.005 mol/L.
Ph
Ph
NCCH3
Ag
Ph
Ph
The room temperature 31P NMR spectra of compounds
1, 2 and 4 all exhibit a broad signal (in the range 4–8 ppm),
ascribed to rapid bond-breaking processes. The absorption
is downfield shifted with respect to the corresponding sig-
nal in the free ligand. The 31P,Ag coupling constant values
and the chemical shifts are typical of species containing
AgP environments [9].
4
Chart 3.
has been recovered. Compounds 1–4 are soluble in acetoni-
trile and DMSO, insoluble in alcohols and diethyl ether. 1
and 2 are moderately soluble also in chlorinated solvents.
Conductivity measurements, as expected, indicated that
the perchlorate complexes 3 and 4 are electrolytes, not only
in MeCN but also in dichloromethane solution, the values
of KM being for these compounds greater than 40 Xꢁ1
cm2 molꢁ1. The carboxylate species 1 and 2 exhibit values
typical of partly ionized species in CH2Cl2.
3.3. Structural studies
Structurally defined adducts of the form AgX:dppf (m:n)
have recently been surveyed and augmented [10]. The most
extensively recorded stoichiometry is of (1:1)(n) adducts, for
which there are now numerous examples. By contrast, as
with other AgX:dppx combinations, adducts of AgX:dppf
2:1 stoichiometry are limited in number, being represented
only by an acetate [11], although that report also records
the synthesis of a 2:1 benzoate. The acetate is a centrosym-
metric tetranuclear array, in which the two independent sil-
ver atoms are (quasi-) four-coordinate, the coordination
number being achieved by virtue of the chelating and/or
bridging coordination modes of the carboxylates; the dppf
ligand bridges the two independent silver atoms of the
asymmetric unit.
3.2. Spectroscopy
The infrared spectra of 1–4 (see Section 2) are consistent
with the formulations proposed, showing all of the bands
required by the presence of the counter-ion and of the
diphosphine donors [4]. The bands due to the phosphine
ligands are only slightly shifted with respect to those of
the free donors. In the far-IR spectra of derivatives 1–4
we assigned, on the basis of a previous report on phos-
phino silver(I) derivatives [5,6], the broad absorptions near
500 cmꢁ1 and those at 450–400 cmꢁ1 to Whiffen’s y and t
vibrations, respectively.
The present array, AgClO4:dppf:MeCN (2:1:4), (3),
is simpler, being an elegant binuclear centrosymmetric
dimer, [{(MeCN)2(O3ClO)Ag}2(P-dppf-P0)], the iron
atom being disposed at the crystallographic inversion
In the cases of carboxylate derivatives it is generally
accepted [7] that it is possible to distinguish between ionic,

2174
A. Cingolani et al. / Inorganica Chimica Acta 359 (2006) 2170–2177
Table 1
centre with the dppf linking the two-symmetry-related sil-
ver atoms through its phosphorus donors (Fig. 1). Ag–P
(Table 1) is appreciably shorter than in the array of
(1:1)2 adducts recently described, presumably because
the complement of other atoms in the silver(I) coordina-
tion sphere are here much weaker donors. In the present
array, interaction with the perchlorate, which approaches
as a unidentate, is feeble; the perchlorate is disordered,
the disorder resolvable in two of the oxygen atoms,
one of which is the donor, the two components of which
lie at disparate distances, long and very long. The
remainder of the coordination environment is made up
of a pair of acetonitrile molecules, one of which is also
disordered (the two components more similar), perhaps
in concert with the perchlorate; silver(I) not infrequently
displays ambiguous coordination environments, and here,
deconvoluted as in Table 1, it might be conjectured that
the longer perchlorate approach corresponds to an
almost exactly trigonal array of the PAgN2 aggregate,
while the shorter is associated with a perturbation of
the latter towards tetrahedral.
Beyond the above, the only other AgX:dpex (2:1)
adducts structurally described are the X = Cl, Br, NCO
derivatives with dppm, also the NCO/dpam, all ‘step’
structures (or close derivatives thereof), and, beyond those,
the NO3/dppp adduct, also a tetranuclear species with
more tenuous relations to the ‘step’ form [12]. It is of inter-
est that the array is further extended here with two further
dppp adducts, the anions both being carboxylates, ‘isoelec-
tronic’ with nitrate but stronger donors, so that it is per-
haps surprising that, at least thus far, it is the latter
forms which are solvated, albeit in one case quite tenu-
ously, although the result is now no longer tetranuclear
in either case, both forms being one-dimensional polymers,
The silver coordination environment(s), AgClO4:dppf:MeCN (2:1:4), 3
Component ‘a’
Atoms
Component ‘b’
Atoms
Parameter
Parameter
˚
Distances (A)
Ag–P
2.368(1)
2.318(9)
2.20(1)
2.59(1)
Ag–N(11)
Ag–N(21a)
Ag–O(1a)
Ag–N(21b)
Ag–O(1b)
2.29(1)
2.94(2)
Angles (ꢁ)
P–Ag–N(11)
P–Ag–N(21a)
N(11)–Ag–N(21a)
P
119.3(2)
145.5(3)
78.6(4)
P–Ag–N(21b)
N(11)–Ag–N(21b)
P
134.8(3)
105.9(4)
343.4
360.0
P–Ag–O(1a)
115.6(3)
91.6(4)
91.2(4)
P–Ag–O(1b)
117.1(3)
71.7(4)
76.6(4)
N(11)–Ag–O(1a)
N(21a)–Ag–O(1a)
N(11)–Ag–O(1b)
N(21b)–Ag–O(1b)
the asymmetric unit in both cases containing two indepen-
dent silver atoms. The polymers lie parallel to the short
axes of their cells, the generator being the unit translation
in each case, otherwise devoid of symmetry, so that the
sequences of the silver atoms are both . . .1212. . . Linkage
of the silvers is achieved in two ways, one being by way of
the dppp ligand, bridging, and the other by bridging
carboxylate units, so that the two strings take the
form. . .. . .Ag(P-dppp-P)Ag(OCO)(1or2)Ag(P. . .; there is a
tendency toward two-coordination about (most of) the sil-
ver atoms, but . . . see below. In detail:
In Agtfa:dppp:H2O (2:1:1) Æ (MeOH) (1), (Fig. 2;
Table 2) disparate silver atoms are linked by the P-dppp-
P0 linker (torsions, successively, 36.1(9), 175.7(8),
174.0(8), 39.5(8)ꢁ), the phosphorus atoms, together with
Fig. 1. A single molecule of AgClO4:dppf:MeCN (2:1:4), 3.

A. Cingolani et al. / Inorganica Chimica Acta 359 (2006) 2170–2177
2175
Fig. 2. A strand of the one-dimensional polymer of Agtfa:dppp:H2O (2:1:1)(1j1), 1, projected normal to the polymer axis which lies parallel to b.
quasi-trans carboxylate oxygens, dominating the coordina-
Table 2
Silver environments, Agtfa:dppp:H2O (2:1:1)(1|1) Æ (MeOH), 1
tion environments quasi-linearly. The two silver atoms,
˚
separated by 4.989(2) A, are loosely linked by the water
Ag(1)
Ag(2)
molecule oxygen, completing an eight-membered ring.
The other Ag(1). . .Ag(2) distance (3.009(2) A) is shorter,
Atoms
Parameter
Atoms
Parameter
˚
˚
Distances (A)
Ag(1)–P(1)
Ag(1)–O(11)
Ag(1)–O(w)
Ag(1). . .O(21ii)
Ag(1). . .Ag(2)
being bridged by carboxylate 1; the second carboxylate is
swivelled so that one of its oxygen atoms has no close inter-
action with a silver atom; rather the first oxygen, O(21)
interacts at a long distance with the other silver semi-bridg-
ing. Difference map residues model persuasively as lattice
2.382(3)
2.19(1)
2.76(1)
2.92(1)
4.989(2)
Ag(2)–P(2)
2.367(3)
2.25(1)
2.45(1)
2.76(1)
3.00(1)
Ag(2)–O(21)
Ag(2)–O(12i)
Ag(2)–O(w)
Ag(1). . .Ag(2ii)
˚
methanol (C–O 1.39(3), O. . .O(w) („O(3)) 2.73(2) A)
Angles (ꢁ)
P(1)–Ag(1)–O(11)
P(1)–Ag(1)–O(w)
161.3(4)
105.0(2)
P(2)–Ag(2)–O(21)
P(2)–Ag(2)–O(w)
152.1(3)
108.0(2)
115.8(3)
87.1(4)
92.5(3)
85.9(4)
although no associated hydrogen atoms were located.
In Agac:dppp:MeOH (2:1:0.5) ꢀ (3 12 H2O) ð2Þ (Fig. 3,
Table 3), the Ag. . .Ag distance spanned by the P-dppp-P0
P(2)–Ag(2)–O(12ii)
O(21)–Ag(2)–O(w)
O(12ii)–Ag(2)–O(w)
O(21)–Ag(2)–O(12ii)
Ag(2)–O(12ii)–C(11ii)
Ag(2)–O(21)–C(21)
O(11)–Ag(1)–O(w)
Ag(1)–O(11)–C(11)
82.3(4)
˚
ligand is greater (5.251(2) A; ligand torsions: ꢁ38.4(4),
ꢁ175.0(4), ꢁ173.2(4), ꢁ38.7(4)ꢁ); the incipiently spanning
121.8(10)
121.1(9)
128.9(10)
solvent oxygen, now methanolic, ‘contacts’ the two silver
˚
atoms at 3.91(1), 2.80(1) A. The diminution in this tie is
Transformations of the asymmetric unit: i, ii x, 1 + y, z. The two associ-
compensated by a strengthening in the other Ag. . .Ag link-
age, now 2.887(1) rather than 2.92(1) A in consequence
of both carboxylates now bridging. One of the latter is
˚
ated silver atoms lie 0.09(3), 1.11(3) A out of the plane of carboxylate 1,
˚
˚
Ag(2) 0.55(3) A out of the plane of carboxylate 2.
Fig. 3. A strand of the one-dimensional polymer of Agac:dppp:MeOH (2:1:0.5)(1j1), 2, projected normal to the polymer axis which lies parallel to a.

2176
A. Cingolani et al. / Inorganica Chimica Acta 359 (2006) 2170–2177
Table 3
Table 4
Silver environments, Agac : dppp : MeOHð2 : 1 : 1=2Þð1j1Þ ꢀ ð3 12 H2OÞ; 2
Selected geometries, AgClO4:dppe:MeCN (1:1:1)(1|1), 4
Ag(1)
Ag(2)
Atoms
Parameter
Atoms
Parameter
˚
Atoms
Parameter
Atoms
Parameter
Distances (A)
Ag–P(1)
Ag–P(2)
2.414(2)
2.416(2)
Ag–O(1)
Ag–N(11)
2.676(5)
2.715(9)
˚
Distances (A)
Ag(1)–P(1)
2.354(2)
2.19(1)
2.57(3)
2.194(7)
2.887(1)
Ag(2)–P(2i)
Ag(2)–O(21)
Ag(2)–O(12)
Ag(2)–O(120)
Ag(2)–O(3)
2.379(2)
2.535(5)
2.14(1)
2.26(2)
2.80(1)
Ag(1)–O(110)
Ag(1)–O(11)
Ag(1). . .O(22)
Ag(1). . .Ag(2)
Angles (ꢁ)
P(1)–Ag–P(2)
P(1)–Ag–O(1)
P(1)–Ag–N(11)
Ag–O(1)–Cl
153.43(6)
97.3(1)
108.4(2)
109.8(3)
P(2)–Ag–O(1)
107.9(1)
84.3(2)
81.1(2)
P(2)–Ag–N(11)
O(1)–Ag–N(11)
Ag–N(11)–C(11)
150.5(10)
Angles (ꢁ)
P(1)–Ag(1)–O(110)
P(1)–Ag(1)–O(22)
O(110)–Ag(1)–O(22)
P
117.2(4)
148.0(2)
88.1(4)
P(2i)–Ag(2)–O(21)
P(2i)–Ag(2)–O(12)
P(2i)–Ag(2)–O(120)
100.9(1)
150.1(4)
153.8(4)
solvates have been recorded for adducts of 1:1 stoichiome-
try, the majority of these being with dpem (= Ph2E-
CH2EPh2, E = P, As) ligands [13] in a binuclear form in
which two predominantly two-coordinate silver atoms are
linked into a binuclear Ag(E-dpem-E0)2Ag eight-membered
ring, with the silver coordination number augmented by
interactions with anion oxygens and solvent nitrogen
(MeCN, py) or oxygen (EtOH). We take the opportunity
to record here the structural characterization of an acetoni-
trile solvated AgX:dppe adduct of 1:1 stoichiometry, being
AgX:dppe:MeCN (1:1:1), 4 (Fig. 4, Table 4). Like the
dppp adducts above, this is a one-dimensional polymer
(Fig. 4), one formula unit comprising the asymmetric unit
of the structure which is propagated along a by inversion
and translation. All Ag. . .Ag linkages here are provided
by dppe, the mid-points of the C(H2)–C(H2) bonds from
two independent linkages lying at successive inversion cen-
tres with necessarily trans torsions. The silver atom is
quasi-linearly coordinated by a pair of phosphorus atoms
from successive ligands, the coordination number being
increased to four by rather distant approaches from the sol-
vent molecule and unidentate OClO3 anion (Table 4).
353.3
O(11)–Ag(1)–P(1)
O(11)–Ag(1)–O(22)
O(11)–Ag(1)–O(110)
103.9(6)
105.7(6)
21.8(7)
O(21)–Ag(2)–O(12)
O(21)–Ag(2)–O(120)
O(12)–Ag(2)–O(120)
108.4(4)
101.6(5)
20.4(6)
Transformation of the asymmetric unit: i, x ꢁ 1, y, z.
disordered over two sets of sites, presumedly in concert
with the occupancy of the methanol solvated, the latter
refining to 0.5. Which carboxylate is a concomitant of the
solvent’s presence is more problematic; O(3) lies closest
to Ag(2), but the geometries associated with O(12,120) are
of little assistance in defining the association; the difference
in Ag(1)–O(11,110) is more significant, but Ag(1) lies much
further from O(3). It may be noteworthy that
0
˚
O(3). . .O(12,12 ) are 2.73(2), 3.39(2) A, the former distance
typical of a hydrogen-bonding contact. The relativity in
coordination between ac and tfa and between H2O versus
MeOH is interesting; the weaker solvent donor is a con-
comitant of the stronger anion donor.
By contrast with the present relatively limited number of
2:1 AgX:dppx solvated adducts, a considerable number of
Fig. 4. View of the polymer of AgClO4:dppe:MeCN (1:1:1)(1j1), 4, propagated along a.

A. Cingolani et al. / Inorganica Chimica Acta 359 (2006) 2170–2177
2177
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