Synthesis, spectroscopic and structural characterization of novel adducts of some silver(I) salts with the ambidentate donor PPh2py

Article abstract of DOI:10.1016/j.ica.2005.12.031

Syntheses, spectroscopic (IR, ¹H and ³¹P NMR) and some 'low' -temperature single-crystal X-ray structural characterizations are reported for a wide variety of adducts of AgX:PPh₂py (:S) (n:m(:x)) (X = Cl, Br, I, NO₂, SCN, ClO₄, BF₄, O₂CCF₃ (tfa), O₂CCH₃ (ac), O₂CC₃F₇ (hefb), S₂CN(C₂H₅)₂ (dtc), 1/2 multiscripts(SO, 4, mml:none(), mml:none(), 2 -); PPh₂py = L = diphenyl-2-pyridylphosphine) stoichiometry. All compounds are binuclear, a wide range of Ag?Ag distances being found, bridging entities being diverse, either anionic X or the P,N-ambidentate ligand PPh₂py. PPh₂py acts as a terminal P-donor in Agdtc: PPh₂py (1:1)₂ and in [(Ph₂py)₂Ag(μ-Cl)₂Ag(PPh₂py)(NCMe)], but fully utilizes its coordinating capabilities in [(MeCN)Ag(μ-PPh₂py)₃Ag(OH₂)](ClO₄)₂ and [(NO₂)Ag(μ-PPh₂py)₂Ag(O₂N)]. Comparison is made between the latter compound and the analogous species [(NO₂)Ag(μ-PPh₂bim)₂Ag(O₂N)] (PPh₂bim = L′ = 1-benzyl-2-imidazolyldiphenylphosphine).

Full text of DOI:10.1016/j.ica.2005.12.031

Inorganica Chimica Acta 359 (2006) 2183–2193
www.elsevier.com/locate/ica
Synthesis, spectroscopic and structural characterization of novel
adducts of some silver(I) salts with the ambidentate donor PPh2py
a
a
a,
*
Augusto Cingolani , Effendy b,c, Domenico Martini , Claudio Pettinari
,
c
c
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 Biomolecular, Biomedical and Chemical Sciences, The University of Western Australia, Crawley, WA 6009, Australia
b
c
Jurusan Pendidikan Kimia, FMIPA Universitas Negeri Malang, Jalan Surabaya 6, Malang 65145, Indonesia
Received 11 November 2005; accepted 11 December 2005
Available online 8 February 2006
Abstract
1
Syntheses, spectroscopic (IR, H and 31P NMR) and some ‘low’ -temperature single-crystal X-ray structural characterizations are
reported for a wide variety of adducts of AgX:PPh2py (:S) (n:m(:x)) (X = Cl, Br, I, NO2, SCN, ClO4, BF4, O2CCF3 (tfa), O2CCH3
(ac), O2CC3F7 (hefb), S2CN(C2H5)2 (dtc), 1/2 SO42ꢀ; PPh2py = L = diphenyl-2-pyridylphosphine) stoichiometry. All compounds are
binuclear, a wide range of Agꢁ ꢁ ꢁAg distances being found, bridging entities being diverse, either anionic X or the P,N-ambidentate ligand
PPh2py. PPh2py acts as a terminal P-donor in Agdtc: PPh2py (1:1)2 and in [(Ph2py)2Ag(l-Cl)2Ag(PPh2py)(NCMe)], but fully utilizes its
coordinating capabilities in [(MeCN)Ag(l-PPh2py)3Ag(OH2)](ClO4)2 and [(NO2)Ag(l-PPh2py)2Ag(O2N)]. Comparison is made
between the latter compound and the analogous species [(NO2)Ag(l-PPh2bim)2Ag(O2N)] (PPh2bim = L0 = 1-benzyl-2-
imidazolyldiphenylphosphine).
ꢀ 2005 Elsevier B.V. All rights reserved.
Keywords: Silver; 31P NMR; X-ray crystal structure; Ambidentate PN donor; Phosphine ligands
1. Introduction
boxylate), E = P, As, Sb, n = 1 [6,7], 2 [8], 3 [9], 4 [10]. Sim-
ilar adducts MX:L (1:n) (n = 1–4) for ER2R0 ligands
(R ¼ R0) (n predominantly 1) have been only sporadically
investigated. The multidentate 2-pyridyl-phosphines of
the type PPhxpy3ꢀx (x = 0, 1, 2) are potentially interesting
ligands in this respect. They can act in unidentate terminal
[11–13], bridging [14,15], or chelating modes [16,17].
Changes in coordination mode from the solid to solution
state have been reported [18].
The ambidentate PPh2py is a suitable ligand for the
formation of multinuclear complexes in which the metal
atoms are held in close proximity, thus allowing direct
metal–metal interactions as in the dinuclear dicationic
1:1 gold complex containing PPh2py which is distin-
guished by a very short Au–Au contact [19]. Mixed-metal
complexes (Au–Ag and Au–Cu) have also been prepared
[20]. A number of papers [21–24] have described other
coinage metal derivatives containing PPh2py, but to date
The coordination chemistry of tertiary phosphines is a
well-established field of research that allows systematic
investigation of the possible coordination modes of oxya-
nions such as NO3ꢀ, ClO4ꢀ, and NO2 to Ag(I) [1–4]
and Cu(I) ions [5]. It is well-known that interesting struc-
tural variations within the series MX/(PR3)n result from
the different coordination modes of the anions. A recent
series of papers has augmented and summarized the con-
temporary status of the structural definition of families of
simple complexes of the form MX:EPh3 (1:n), M = univa-
lent copper or silver, X = simple halide or pseudohalide
(Cl, Br, I, SCN) or oxyanion (ClO4ꢀ, NO3ꢀ, or simple car-
ꢀ
*
Corresponding author. Tel.: +39 0737 402234; fax: +39 0737 637345.
E-mail address: claudio.pettinari@unicam.it (C. Pettinari).
0020-1693/$ - see front matter ꢀ 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2005.12.031

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A. Cingolani et al. / Inorganica Chimica Acta 359 (2006) 2183–2193
no systematic investigation on the interaction between this
P,N-donor and silver salts has been reported. Here, we
describe the synthesis and spectroscopic characterization
of a number of novel AgX:PPh2py adducts, supported
by four single-crystal X-ray studies to assist in under-
standing the relationships between molecular packing,
coordinating ability of Xꢀ, donor capacity, and the Tol-
man cone angle of the ancillary ligand PPh2py. Compar-
ison is also made with an AgNO2 derivative of the
analogous P,N-donor ligand PPh2bim (PPh2bim = 1-ben-
zyl-2-imidazolyldiphenylphosphine) [25–28]. Our results
demonstrate that remarkably stable neutral silver com-
plexes showing different silver(I) coordination environ-
ments can be easily synthesized, ranging from dinuclear
systems containing the P,N-donor coordinated as a termi-
nal ligand through the P center, to dinuclear systems con-
taining the same P,N-donor coordinated in a bridging
bidentate fashion.
amounts of materials should be prepared, and these should
be handled with great caution.
2.2.1. {Bis(diphenyl-2-pyridylphosphine)-
dibromodisilver(I))}, [(L)2Ag2Br2)] (1)
To an MeCN solution containing 0.149 g (0.569 mmol)
of PPh2py, 0.082 g (0.436 mmol) of AgBr was added. The
reaction was stirred under reflux for 20 h in a round-bot-
tomed flask protected from the light. A colorless precipitate
formed which was filtered off, washed with MeCN, and
identified as compound 1 (77% yield). M.p. 259–261 ꢁC.
Anal. Calc. for C17H14AgBrNP: C, 45.27; H, 3.13; N,
3.11. Found: C, 45.23; H, 3.10; N, 3.04%. 1H NMR
(CDCl3, 200 MHz, 293 K): 7.23–7.39 (11H, Hpy + HPh),
7.51–7.64 (m, 1H, Hpy), 7.77 (t, 1H, HPh), 8.65 (d, 1H,
Hpy). 31P (CDCl3, 400 MHz, 293 K): 5.7s. 31P (CDCl3,
1
400 MHz, 293 K): 8.1 (d, J(31P–Ag): 412 Hz). IR (nujol
mull, cmꢀ1): 1563m, 1555m (C C and C N), 1459w,
. . .
. . .
•
•
1377w, 986m, 768m, 745w, 515w, 504w, 491m, 433s. Km
2. Experimental
(CH2Cl2, conc. = 1.0 · 10 ꢀ3 M): 2.8 Xꢀ1 cmꢀ2 molꢀ1
.
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,S) were performed in-house with a Fisons Instru-
ments 1108 CHNS-O Elemental Analyser. IR spectra were
recorded from 4000 to 100 cmꢀ1 with a Perkin–Elmer Sys-
tem 2000 FT-IR instrument. 1H-, 13C- and 31P NMR spec-
tra were recorded on a VXR-200 (200 MHz for 1H,
50 MHz for 13C) or on a Mercury Plus Varian 400 NMR
spectrometer (400 MHz for 1H, 100 MHz for 13C, and
162.1 MHz for 31P). H and C chemical shifts are reported
in ppm vs. SiMe4, P chemical shifts in ppm vs. H3PO4
85%. The electrical conductances of the dichloromethane
solutions were measured with a Crison CDTM 522 conduc-
timeter at room temperature.
2.2.2. {Bis(diphenyl-2-pyridylphosphine)diiododisilver(I))},
[(L)2Ag2I2] (2)
Compound 2 was prepared by the reaction of 0.149 g
(0.569 mmol) of PPh2py with 0.102 g (0.434 mmol) of
AgI. The reaction was stirred under reflux for 20 h in a
round-bottomed flask protected from the light. A colorless
precipitate formed which was filtered off, washed with
MeCN, and identified as compound 2 (71% yield). M.p.
271–272 ꢁC. Anal. Calc. for C17H14AgINP: C, 41.00; H,
2.83; N, 2.81. Found: C, 40.71; H, 2.92; N, 2.71%. 1H
NMR (CDCl3, 200 MHz, 293 K): 7.18br, 7.25–7.36br
(12H, Hpy + HPh), 7.50–7.55 (1H, Hpy), 8.67 (br, 1H,
Hpy). 31P (CDCl3, 400 MHz, 293 K): 0.3s. 31P (CDCl3,
1
400 MHz, 293 K): 2.1 (d, J(31P–Ag): 397 Hz). IR (nujol
mull, cmꢀ1): 1566m, 1558m (C C and C N), 1459w,
. . .
. . .
•
•
1374m, 1149m, 1090m, 761m, 742m, 511s, 500w, 393s.
2.1. Spectroscopic data of the ligands
Km (CH2Cl2, conc. = 1.0 · 10ꢀ3 M): 0.8 Xꢀ1 cmꢀ2 molꢀ1
.
2.1.1. PPh2py, L, (diphenyl-2-pyridylphosphine)
2.2.3. Bis{(diphenyl-2-pyridylphosphine)bis(diethyldithio-
carbamato)disilver(I)}, [(L)2Ag2(dtc)2] (3)
1H NMR (CDCl3, 200 MHz, 293 K): d 7.04d, 7.06–
7.15m, 7.32–7.40m, (12H, Hpy + HPh), 7.56–7.51 (m, 1H,
Hpy), 8.70 (d, 1H, Hpy). 31P NMR (CDCl3): d ꢀ4.0s. IR
(nujol mull, cmꢀ1): 1566w, 1555w, 509s, 502s, 486s,
432m, 418m, 402m, 392m, 280w, 269w, 247w.
Compound 3 was prepared by the reaction of 0.149 g
(0.569 mmol) of PPh2py with 0.111 g (0.437 mmol) of
silver diethyltiocarbamate (Agdtc) in acetonitrile (15 ml).
The solution was stirred under reflux for 20 h in a round-
bottomed flask protected from the light. Upon slow evap-
oration at room temperature, small crystals formed that
were identified as compound 3 (38% yield). M.p. 164–
165 ꢁC. Anal. Calc. for C22H24AgN2P2: C, 50.87; H, 4.66;
N, 5.39; S, 12.35. Found: C, 50.42; H, 4.88; N, 5.33; S,
2.1.2. PPh2bim, L0, (1-benzyl-2-imidazolyl)diphenyl-
phosphine)
1H NMR (CDCl3, 400 MHz, 293 K): d 5.48 (s, 2H,
CH2), 7.08–7.63 (m, 17H, CHarom). 31P NMR (CDCl3): d
ꢀ32.6s. IR (nujol mull, cmꢀ1): 618s, 570w, 552w, 542w,
510s, 505s, 465m, 455m, 420w, 285m.
1
12.21%. H NMR (CDCl3, 200 MHz, 293 K): 1.31 (t, 6H,
CH3dtc), 3.99 (q, 4H, CH2dtc), 7.23–7.26, 7.33–7.40
(m, 12H, Hpy + HPh), 7.54–7.64 (1H, Hpy), 8.73 (d, 1H,
Hpy). 31P NMR (CDCl3, MHz, 294.1 K): 10.5s. 31P
NMR (CDCl3, MHz, 218.2 K): 11.7 br. IR (nujol mull,
cmꢀ1): 1459w, 1376w, 1261s, 1202m, 1155m, 1086br,
1010, 976br (C@S), (C–N), 721m, 691w, 669s, 618s
2.2. Syntheses and spectroscopic data of complexes
Safety note. Perchlorate salts of metal complexes with
organic ligands are potentially explosive! Only small

A. Cingolani et al. / Inorganica Chimica Acta 359 (2006) 2183–2193
2185
(C–S), 562s, 507w, 409s, 277s. Km (CH2Cl2, conc. = 1.0 ·
10ꢀ3 M): 1.2 Xꢀ1 cmꢀ2 molꢀ1
293 K): 9.28s. 31P (CDCl3, 400 MHz, 223 K): 4.4 (d,
1
.
1J(31P–Ag): 362 Hz), 8.7 (d, J(31P–Ag): 426 Hz), 10.4 (d,
1J(31P–Ag): 572 Hz). IR (nujol mull, cmꢀ1): 1566m
. . .
. . .
2.2.4. {Bis(diphenyl-2-pyridylphosphine)sulfatodisilver(I)},
[(L)2Ag2(SO4)] (4)
(C C and C N), 1459w, 1429m, 1377m, 1094m, 980m,
•
•
768m, 739w, 514s, 501w, 394s. Km (CH2Cl2, conc. =
Compound 4 was prepared by the reaction of 0.149 g
(0.569 mmol) of PPh2py with 0.68 g (0.218 mmol) of
Ag2SO4 in MeCN. The reaction was stirred under reflux
for 20 h in a round-bottomed flask protected from the
light. A gray precipitate formed, which was filtered off,
washed with MeCN and identified as compound 4 (33%
yield). M.p. 229–230 ꢁC. Anal. Calc. for C34H28Ag2-
N2O4P2S: C, 48.71; H, 3.37; N, 3.34; S, 3.82. Found: C,
48.31; H, 3.22; N, 3.45; S, 3.93%. 1H NMR (CDCl3,
200 MHz, 293 K): 7.15–7.27 (m, 24H, Hpy + HPh), 7.43
(m, 2H, Hpy), 8.93 (d, 2H, Hpy). 31P NMR (CDCl3,
400 MHz, 293 K): 14.5s. 31P NMR (CDCl3, 400 MHz,
223 K): 15.3 (d, 1J(31P–Ag): 648 Hz). IR (nujol mull,
1.0 · 10ꢀ3 M): 0.9 Xꢀ1 cmꢀ2 molꢀ1
.
2.2.7. {(Aqua)tris(diphenyl-2-pyridylphosphine)-
dithiocyanatodisilver(I)} [(L)3Ag2(SCN)2(H2O)2] (7)
Compound 7 has been prepared by reaction of 0.149 g
(0.569 mmol) of PPh2py with 0.072 g (0.437 mmol) of
AgSCN in MeCN (20 mL). The reaction was stirred under
reflux for 20 h in a round-bottomed flask protected from
the light. A colorless precipitate formed, which was filtered
off, washed with MeCN and identified as compound 7 (25%
yield). M.p. 156–157 ꢁC. Anal. Calc. for C53H46Ag2-
N5O2P3S2: C, 54.98; H, 4.00; N, 6.05; S, 5.54. Found: C,
55.24; H, 4.22; N, 6.31; S, 5.60%. 1H NMR (CDCl3,
200 MHz, 293 K): 1.60 (s, 2H, H2O), 7.24–7.46 (m, 36H,
Hpy + HPh), 7.55–7.62 (m, 1H, Hpy), 8.69 (d, 3H, Hpy).
31P (CDCl3, 400 MHz, 293 K): 10.1s. 31P (CDCl3,
400 MHz, 223 K): 5.7 (d, 1J(31P–Ag): 378 Hz), 11.6 (d,
1J(31P–Ag): 546 Hz). IR (nujol mull, cmꢀ1): 3300br (OH),
2110m, 2066m (SCN), 1461w, 1380w, 1085s, 1310s, 739m,
518m, 506w, 501m, 458w, 277s. Km (CH2Cl2, conc. =
cmꢀ1): 1561m (C C and C N), 1454w, 1373w, 1137s,
. . .
. . .
•
•
1104s, 1074s br, 1026s, 989m, 941m, 739m, 720m, 600w,
591w, 521w, 517w, 502s, 492sh, 445br, 420br, 399br, 280s.
Km (CH2Cl2, conc. = 1.0 · 10ꢀ3 M): 3.4 Xꢀ1 cmꢀ2 molꢀ1
.
2.2.5. {Bis(diphenyl-2-pyridylphosphine)dinitrito-
disilver(I)}, [(L)2Ag2(NO2)2] (5)
Compound 5 was prepared by the reaction of 0.290 g
(1.14 mmol) of PPh2py with 0.100 g (0.65 mmol) of AgNO2
in methanol (20 mL). The reaction was stirred under reflux
for 8 h in a round-bottomed flask protected from the light.
A colorless precipitate formed which was filtered off,
washed with diethyl ether and shown to be compound 5
(75% yield). Material for the X-ray work was recrystallized
from methanol solution. Mp. 114–115 ꢁC. Anal. Calc. for
C17H14AgN2O2P: C, 48.95; H, 3.38; N, 6.72. Found: C,
49.01; H, 3.45; N, 6.72%. 1H NMR (CDCl3, 200 MHz,
293 K): 7.1 (d, 1H, Hpy or HPh), 7.2–7.6 (m, 11H,
Hpy + HPh), 7.7 (m, 1H, Hpy), 8.90 (d, 1H, Hpy). 31P
NMR (CDCl3, 400 MHz, 223 K): 17.8 (d, 1J(31P–Ag):
648 Hz). IR (nujol mull, cmꢀ1): 1683s, 1651s, 1557s,
1455s, 1373s, 1152s 1096s (NO2) 829s, 772m, 740m, 722s,
691m, 633s, 523m, 503m, 487m, 450s, 432s. Km (CH2Cl2,
1.0 · 10ꢀ3 M): 66.6 Xꢀ1 cmꢀ2 molꢀ1
.
2.2.8. {(Aqua)(acetonitrile)tris(diphenyl-2-
pyridylphosphine)bis(perchlorato)disilver(I)},
[(L)3Ag2(ClO4)2(H2O)(MeCN)] (8)
Compound 8 has been obtained by the reaction of
0.150 g (0.57 mmol) of PPh2py with 0.091 (0.44 mmol) of
AgClO4 in MeCN. The reaction was stirred under reflux
for 20 h in a round-bottomed flask protected from the
light. A colorless precipitate formed, which was filtered
off, washed with MeCN, and identified as compound 8
(32% yield). The compound was re-crystallised from
MeCN. M.p. 264 ꢁC. Anal. Calc. for C53H47Ag2Cl2-
N4O9P3: C, 50.38; H, 3.75; N, 4.43. Found: C, 50.45; H,
3.56; N, 4.23%. 1H NMR (CDCl3, 200 MHz, 293 K):
1.68 (br, 2H, H2O), 6.8br, 7.0br, 7.10–7.38m (36H,
Hpy + HPh), 7.5–7.7 (br, Hpy), 9.6 (br, 1H, Hpy). 31P
NMR (CDCl3, 200 MHz, 293 K): 11.6 (d, 1J(31P–Ag):
453 Hz), 11.5br. 31P NMR (CDCl3, 200 MHz, 218.2 K):
conc. = 1.0 · 10ꢀ3 M): 0.5 Xꢀ1 cmꢀ2 molꢀ1
.
2.2.6. {(Acetonitrile)tris(diphenyl-2-pyridylphosphine)-
dichlorodisilver(I)}, [(L)3Ag2Cl2(MeCN)] (6)
10.8 (d, J(31P–Ag): 490 Hz), 10.9br. 31P NMR (CDCl3,
1
To an MeCN solution containing 0.149 g (0.569 mmol)
of PPh2py, 0.063 g (0.439 mmol) of AgCl was added. The
reaction was stirred under reflux for 20 h in a round-bot-
tomed flask protected from the light. A colorless precipitate
formed which was filtered off, washed with MeCN, and
identified as compound 6 (52% yield). Crystals for the X-
ray work were obtained from MeCN solution. M.p. 201–
202 ꢁC. Anal. Calc. for C53H45Ag2Cl2N4P3: C, 56.96; H,
4.06; N, 5.01. Found: C, 57.03; H, 4.43; N, 5.21%. 1H
NMR (CDCl3, 200 MHz, 293 K): d 2.0 (s, 3H, CH3CN),
7.23–7.39 (33H, Hpy + HPh), 7.64–7.51 (3H, Hpy), 7.77 (t,
3H, HPh), 8.72 (d, 3H, Hpy). 31P (CDCl3, 400 MHz,
400 MHz, 293 K): 11.3 (d, 1J(31P–Ag): 462 Hz), 11.4br.
31P NMR (CDCl3, 400 MHz, 223 K): 10.5 (d, J(31P–Ag):
1
467 Hz), 10.6 (br), 19.6 (d, J(31P–Ag): 611 Hz). IR (nujol
1
mull, cmꢀ1): 2921w, 2862w, 1586s (C C and C N),
. . .
. . .
•
•
1459w, 1436w, 1377w, 1162s, 1097w, 1058s (ClO4ꢀ), 918s,
748m, 638s, 621w (ClO4ꢀ), 521w, 506w, 488m, 442s. Km
(CH2Cl2, conc. = 1.0 · 10ꢀ3 M): 7.6 Xꢀ1 cmꢀ2 molꢀ1
.
2.2.9. {Tris(diphenyl-2-pyridylphosphine)-
bis(tetrafluoroborato)disilver(I)}, [(L)3Ag2(BF4)2] (9)
Compound 9 was prepared by the reaction of 0.300 g
(1.14 mmol) of PPh2py with 0.156 g (0.8 mmol) of AgBF4

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A. Cingolani et al. / Inorganica Chimica Acta 359 (2006) 2183–2193
in EtOH (15 mL). The reaction was stirred under reflux for
20 h in a round-bottomed flask protected from the light. A
colorless precipitate formed which was filtered off and iden-
tified as compound 9 (43% yield). M.p. 264 ꢁC. Anal. Calc.
for C51H42Ag2B2F8N3P3: C, 51.95; H, 3.59; N, 3.56. Found:
AgO2CC3F7 in ethanol (15 mL). The reaction was stirred
under reflux for 20 h in a round-bottomed flask protected
from the light. The solution was then evaporated and the
residue washed with diethyl ether. A microcrystalline pre-
cipitate formed that has been identified as compound 12
(55% yield). Anal. Calc. for C59H46Ag2F14N3O6P3: C,
48.28; H, 3.16; N, 2.86. Found: C, 48.42; H, 3.05; N,
2.91%. 1H NMR (CDCl3, 200 MHz, 293 K): 2.05 (br,
2H, H2O), 6.8–7.6 (m, 39H, Hpy + HPh), 9.3 (br, 3H,
Hpy). 31P (CDCl3, 400 MHz, 293 K): 13.0s. 31P (CDCl3,
400 MHz, 223 K): 17.2 (d, 1J(31P–Ag): 652 Hz), 8.0 (d,
1J(31P–Ag): 465 Hz), 8.0 (br). IR (nujol mull, cmꢀ1):
3300br, 1679s, 1650s, 1576m, 1564m, 1163s, 1104m,
1070m, 997m, 960m, 919m, 542w, 516m, 503m, 480m,
444br, 399br, 264br. Km (CH2Cl2, conc. = 1.0 · 10ꢀ3 M):
1
C, 52.13; H, 3.48; N, 4.00%. H NMR (CDCl3, 200 MHz,
293 K): 6.9–7.0, 7.18–7.38 (m, 36H, Hpy + HPh), 7.56–7.77
(m, 1H, Hpypy), 9.40 (d, 1H, Hpy). IR (nujol mull, cmꢀ1):
. . .
. . .
. . .
1584s and 1570m (C O, C C and C N), 1455w,
•
•
•
1374w, 1285m, 1090m, 1051m (BF4ꢀ), 846m, 771w (BF4ꢀ),
745w, 722m, 520w (BF4ꢀ), 506w, 487m, 417s, 251s. Km
(CH2Cl2, conc. = 1.0 · 10ꢀ3 M): 17.2 Xꢀ1 cmꢀ2 molꢀ1
.
2.2.10. {Diaquatris(diphenyl-2-pyridylphosphine)-
diacetatodisilver(I)}, [(L)3Ag2(O2CCH3)2(H2O)2] (10)
Compound 10 was prepared by reaction of 0.149 g
(0.569 mmol) of PPh2py with 0.72 g (0.43 mmol of AgO2-
CCH3) in ethanol (15 mL). The reaction was stirred under
reflux for 20 h in a round-bottomed flask protected from
the light. The solution was evaporated and the residue
extracted with dichloromethane. The solution was evapo-
rated and an oil formed which was identified as compound
10 (29% yield). Anal. Calc. for C55H52Ag2N3O6P3: C, 56.96;
13.7 Xꢀ1 cmꢀ2 molꢀ1
.
2.2.13. {Bis(1-benzyl-2-imidazolyldiphenylphosphine)-
dinitritodisilver(I)}, [(L0)2Ag2(NO2)2] (13)
To a stirred acetonitrile solution (10 mL) of PPh2bim
(0.40 g, 1.16 mmol), AgNO2 (0.153 g, 1.0 mmol) at room
temperature was added. The solution was then stirred under
reflux for 24 h, then left to evaporate until small crystals of
the analytical sample were obtained. (40% Yield). Anal.
Calc. for C22H19AgN3O2P: C, 53.25; H, 3.86; N, 8.47.
1
H, 4.52; N, 3.62. Found: C, 56.62; H, 4.65; N, 3.51%. H
NMR (CDCl3, 200 MHz, 293 K): 2.05 (br, 7H, H2O +
CH3), 7.22–7.42 (m, 39H, Hpy + HPh), 7.49–7.56, 7.65 (m,
3H, Hpy), 8.78 (d, 3H, Hpy). 31P NMR (CDCl3, 400 MHz,
223 K): 8.7 (d, 1J(31P–Ag): 447 Hz), 8.7 (br). IR (nujol mull,
cmꢀ1): 3300br, 1630br, 1461w, 1376m, 1096s, 504s, 153m.
1
Found: C, 53.11; H, 3.75; N, 8.41%. H NMR (CDCl3,
400 MHz, 293 K): d 5.15, (s, 2H, CH2), 6.62 (s br, 2H,
CHarom), 7.0–7.3 (m, 3H, CHarom), 7.3–7.6 (m, 11H,
CHarom), 7.73 (s, 1H, CHarom). 31P NMR (CDCl3): d ꢀ6.3
(br). IR (nujol mull, cmꢀ1): 1373s, 1152s, 1096s, (NO2)
618s, 573w, 550w, 537s, 500s, 470w, 455w, 280m. Km
Km (CH2Cl2, conc. = 1.0 · 10ꢀ3 M): 17.0 Xꢀ1 cmꢀ2 molꢀ1
.
2.2.11. {Triaquatris(diphenyl-2-
pyridylphosphine)bis(trifluoroacetato)-disilver(I)},
[(L)3Ag2(O2CCF3)2(H2O)3] (11)
(CH2Cl2, conc. = 1.0 · 10ꢀ3 M): 1.2 Xꢀ1 cmꢀ2 molꢀ1
Recrystallised from MeOH as 13 Æ 2MeOH.
.
Compound 11 has been prepared by reaction of 0.300 g
(1.14 mmol) of PPh2py with 0.097 g (0.43 mmol) of AgO2-
CCF3 (Agtfa) in methanol (15 mL). The reaction was
stirred under reflux for 20 h in a round-bottomed flask
protected from the light. The solution was then left for
48 h at ꢀ10 ꢁC. A microcrystalline precipitate formed that
has been identified as compound 11 (29% yield). Anal.
Calc. for C55H48Ag2F6O7P3N3: C, 51.38; H, 3.76; N,
3.27. Found: C, 51.19; H, 3.84; N, 3.11%. 1H NMR
(CDCl3, 200 MHz, 293 K): 2.05 (br, 6H, H2O), 7.2–7.6
(m, 36H, Hpy + HPh), 7.7 (m, 3H, Hpy), 8.8 (d, 3H, Hpy).
31P (CDCl3, 400 MHz, 293 K): 11.3s. 31P (CDCl3,
400 MHz, 223 K): 8.6 (d, 1J(31P–Ag): 445 Hz), 8.6 (br).
IR (nujol mull, cmꢀ1): 3300br (OH) 1675s (CO), 1635br
(OH) 1460sh, 1195m, 1169m, 1156m, 1123m, 1097m,
560w, 542m, 515s, 503s, 490s, 399. Km (CH2Cl2, conc. =
2.3. Structure determinations
Full spheres of low-temperature CCD area-detector dif-
fractometer data were measured (T ca. 153 K; Bruker AXS
instrument, x-scans; monochromatic Mo Ka radiation,
˚
k = 0.71073 A), yielding Nt(otal) reflections, these merging
to N unique (Rint cited) after ‘empirical’/multiscan absorp-
tion correction (proprietary software), N0 with F > 4r(F)
being considered ‘observed’ and used in the full-matrix
least-squares refinements, refining anisotropic displacement
parameters for the non-hydrogen atoms, (x,y,z,Uiso H
being included and constrained at estimates. Conventional
residuals R, Rw (reflection weights: (r2(F) + 0.000nwF2)ꢀ1
are cited at convergence; neutral atom complex scattering
factors were employed within the Xtal 3.7 program system
[29]. Pertinent results are presented below and in the tables
and figures, the latter showing 50% probability amplitude
displacement envelopes for the non-hydrogen atoms,
)
)
1.0 · 10ꢀ3 M): 13.6 Xꢀ1 cmꢀ2 molꢀ1
.
˚
2.2.12. {Diaquatris(diphenyl-2-pyridylphosphine)-
bis(heptafluorobutanoato)-disilver(I)},
[(L)3Ag2(O2CC3F7)2(H2O)2] (12)
Compound 12 has been prepared by reaction of 0.300 g
(1.14 mmol) of PPh2py with 0.138 g (0.431 mmol) of
hydrogen atoms having arbitrary radii of 0.1 A; individual
diversions in procedure are noted under ‘variata’. The
assignment of the pyridyl nitrogen in all cases was clearcut,
on the basis of refinement behaviour and bonding consid-
erations, and the location of other pyridylic hydrogen

A. Cingolani et al. / Inorganica Chimica Acta 359 (2006) 2183–2193
2187
atoms. Full.cif depositions have been lodged with the Cam-
3. Results and discussion
bridge Crystallographic Data Centre, CCDC 284591-
284595.
The reaction of AgX (X = Br, I, dtc, 1/2SO4 and NO2)
with an equimolar quantity of 2-pyridylphosphine (PPh2py)
at room temperature gave rise to the compounds
AgX:PPh2py (1:1)2 1–5 (Chart 1). Under the same conditions
the reactions between PPh2py and AgX (X = Cl, SCN, ClO4,
BF4, ac, tfa, hefb) yield the 3:2 adducts 6–12 (Charts 2 and 3).
Finally, the donor PPh2bim reacts with AgNO2 yielding the
dinuclear species AgNO2:PPh2bim (1:1)2 13 (Chart 4).
These compounds are generally air-stable, colorless
materials, soluble in polar solvents such as acetonitrile,
dimethylformamide and dimethylsulfoxide. They are, how-
ever, insoluble in water, ether and tetrahydrofuran, but
exhibit good solubility in the chlorinated hydrocarbons
CH2Cl2 and CHCl3. Solid samples of these compounds
show generally no sensitivity to light. However, they are
unstable in solution, their chlorinated solvent solutions
often darkening after 24 h.
Conductivity measurements indicated that only the
thiocyanate complex 7 behaves as a 1:2 electrolyte in
dichloromethane solution, whereas the values found for
all the other species suggest strong silver(I)-X interactions.
If this behaviour is postulated for derivatives 1–6 and 13,
taking into account the X-ray single crystal studies (see
below), then, for the case of derivative 8, structurally
characterised, partial dissociation of a P,N-donor ligand
and consequent anion reassociation according to Eq. (1)
must be hypothesised.
2.3.1. Crystal/refinement data
2.3.1.1. Agdtc:L(1:1)2, 3 ” C44H48Ag2N4P2S4, M = 1038.8.
1
ꢀ
˚
˚
Triclinic, space group P1 (Ci , No. 2), a = 8.596(2), b =
11.121(3), c = 12.236(3) A, a = 80.314(4), b = 84.401(4),
c = 69.351(4)ꢁ, V = 1078 A . Dcalc (Z = 1) = 1.600 g cmꢀ3
.
3
l
Mo = 1.21 mmꢀ1; specimen: 0.28 · 0.26 · 0.18 mm; ‘T’min/
max = 0.83. 2hmax = 55ꢁ; Nt = 8783, N = 4756 (Rint
0.024), N0 = 3602; R = 0.044, Rw = 0.055 (nw = 0.4).
=
Variata. One of the ethyl groups of the dithiocarbamate
was disordered with the terminal methyl group disposed to
either side of the anion plane, site occupancies set at 0.5
after trial refinement.
2.3.1.2. AgNO2:L (1:1)2, 5 ” C34H28Ag2N4O4P2, M =
ꢀ
834.3. Triclinic, space group P1, a = 9.0060(5), b =
˚
9.7977(6), c = 10.2235(6) A, a = 68.182(1), b = 87.019(1),
3
c = 83.003(1)ꢁ, V = 831.2 A . Dcalc (Z = 1) = 1.666 g cmꢀ3
.
˚
l
Mo = 1.32 mmꢀ1; specimen: 0.28·0.24·0.18 mm; ‘T’min/max
= 0.78. 2hmax = 75ꢁ; Nt = 16966, N = 8516 (Rint = 0.022),
N0 = 7654; R = 0.030, Rw = 0.036 (nw = 4).
Variata. (x,y,z,Uiso)H were refined throughout.
2.3.1.3. AgCl:L:MeCN (2:3:1), 6 ” C53H45Ag2Cl2N4P3,
ꢀ
M = 1117.5. Triclinic, space group P1, a = 12.360(1),
˚
b = 14.420(1),
c = 15.846(2) A,
a = 99.938(2),
b =
3
˚
104.846(2), c = 111.594(2)ꢁ, V = 2405 A . Dcalc (Z = 2) =
1.545 g cmꢀ3. lMo = 1.07 mmꢀ1; specimen: 0.15 · 0.12 ·
0.10 mm; ‘T’min/max = 0.88. 2hmax = 70ꢁ; Nt = 49724, N =
20454 (Rint = 0.035), N0 = 14706; R = 0.044, Rw = 0.051
(nw = 7).
X
pyPh2P
Ag
Ag
PPh2py
X
2.3.1.4. AgClO4:L:H2O:MeCN (2:3:1:1), 8 ” C53H47Ag2-
Cl2N4O9P3, M = 1263.5. Monoclinic, space group P21=n
1: X = Br
2: X = I
(C52h, No. 14 (variant)), a = 13.058(1), b = 18.099(2), c =
3
˚
˚
C2H5
C2H5
22.561(2) A, b = 98.209(3)ꢁ, V = 5277 A . Dcalc (Z = 4) =
1.59 g cmꢀ3. lMo = 0.99 mmꢀ1; specimen: 0.19 · 0.16 ·
0.03 mm; ‘T’min/max = 0.79. 2hmax = 65ꢁ; Nt = 109843,
N = 18664 (Rint = 0.11), N0 = 10551; R = 0.040, Rw =
0.034 (nw = 5).
S
pyPh2P
C
N
Ag
Ag
C2H5
C2H5
S
S
S
N
C
PPh2py
Variata. (x,y,z,Uiso H were refined throughout. Both
)
3
perchlorates were modelled with disordered oxygen atoms,
all of perchlorate 1 over two sets of sites and O(22–24) of
perchlorate 2, occupancies refining to 0.761(7) and comple-
ment, in each case, presumably concerted.
Ph
P
Ph
Ph
Ph
P
N
N
2.3.1.5. AgNO2:L0:MeOH (1:1:1)2, 13 ” C46H46Ag2-
O
O
O
O
O
O
O
S
Ag
N
Ag
N
Ag
N
Ag
P
N
ꢀ
N6O6P2, M = 1056.6. Triclinic, space group P1, a =
O
˚
8.7780(9), b = 11.369(1), c = 12.292(1) A, a = 73.941(2),
P
Ph
Ph
3
˚
b = 74.066(2), c = 88.544(2)ꢁ, V = 1131.8 A . Dcalc (Z = 1)
Ph
Ph
= 1.551 g cmꢀ3. lMo = 0.99 mmꢀ1; specimen: 0.40 · 0.28
· 0.26 mm; ‘T’min/max = 0.84. 2hmax = 75ꢁ; Nt = 23332,
N = 11558 (Rint = 0.030), N0 = 9687; R = 0.042, Rw =
0.060 (nw = 8).
4
5
Chart 1.

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A. Cingolani et al. / Inorganica Chimica Acta 359 (2006) 2183–2193
Cl
pyPh2P
pyPh2P
PPh2py
NCCH3
Ag
Ag
Cl
6
++
++
H2O
Ag
Ph2P
H3CCN
Ag
N
N
Ph2P
Ph2P
Ph2P
PPh2
PPh2
Ag
[SCN-]2
-
[ClO4
]
2
N
N
N
N
Ag
OH2
OH2
7
8
F3BF
Ag
Ph2P
N
Ph2P
PPh2
Ag
N
N
FBF3
9
Chart 2.
½ðH2OÞAgðl-PPh2pyÞ AgðCH3CNÞꢂþþ2½ClO4ꢀꢂ
! ½ðO3ClOÞAgðl-PPh2pyÞ2AgðOClO3Þꢂ þ PPh2py
þ MeCN þ H2O
400 cmꢀ1 to Whiffen’s y and t vibrations, respectively. No
discernible bands have been detected at low frequencies
in the spectra of 1, 2 and 6 that can be assigned to any
M-halide stretching vibrations, as is consistent with
strongly bonded, bridging halide groups.
In the spectra of 5 and 10–12 there are some bands in the
region 300–200 cmꢀ1, similar to those described in the liter-
ature for other silver(I)-oxyanion derivatives [34] which can
be tentatively assigned to m(Ag–O).
3
ð1Þ
This hypothesis is supported by the presence in the 31P
NMR spectrum (CDCl3 solution) of a signal (at ca.
23 ppm) ascribable to O=PPh2py and by previous reports
in the literature on analogous complexes containing the
bidentate ligand dppm [30].
The spectroscopic behaviour of the counter-ion in
compound 8 is tyꢀpical of an ionic outer-sphere group:
for an ionic ClO4 (Td geometry), only two vibrations
(m3 and m4) are expected to be IR active [35], as are in fact
found at ca. 1090 and 620 cmꢀ1, consistent with the
results found in the single crystal studies. On the other
hand, different absorptions have been found in the spec-
trum of the derivative 9, a number of broad bands
between 1100 and 900 cmꢀ1 and two weak bands at
745 and ꢀ722 cmꢀ1, consistent with a coordinated uniden-
tate BF4 group [36].
In the case of carboxylate derivatives it is generally
accepted [37] that it is possible to distinguish between ionic,
unidentate, chelating bidentate or bridging bidentate
groups on the basis of D values (where D = ma(COO) ꢀ ms-
(COO)), the trend generally being accepted:
In the case of derivatives 7 and 9–12, conductivity mea-
surements support the hypothesized structures in Charts 2
and 3, consistent with the 31P NMR spectra (see below).
Partial dissociation of 11 in solution with the formation
of a dinuclear species [(tfa)Ag(l-PPh2py)2Ag(tfa)] similar
to that reported for an analogous dppm derivative [30] is
also likely, as further indicated by the 31P NMR spectrum.
3.1. Spectroscopy
The infrared spectra of 1–13 (see Section 2) are consis-
tent with the formulations proposed, showing all of the
bands required by the presence of the counterions and of
the phosphorus or arsenic donors [31]. 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 all
derivatives we have assigned, on the basis of previous
reports on phosphino silver(I) derivatives [31–33], the
broad absorptions near 500 cmꢀ1 and those at 450–
D
> D
> D
> D
bridging bidentate
unidentate
ionic
chelating bidentate

A. Cingolani et al. / Inorganica Chimica Acta 359 (2006) 2183–2193
2189
Ph
++
H2O
Ag
Ph2P
N
N
Ph
Ph
P
N
Ph2P
PPh2
Ag
O
O
O
O
[-O2CCH3]2
N
Ag
N
Ag
P
N
N
N
Ph
OH2
Ph
N
10
Ph
13
++
H2O
Ag
Ph2P
Chart 4.
N
solid state have been found to contain three bridging
ambidentate phosphine ligands, a broad signal or a broad
multiplet was observed at room temperature. At 223 K the
spectra exhibit broad triplets that at 193 K split into two
broad doublets at 193 K. This pattern can be explained
assuming that at 223 K, the dynamical processes that aver-
age the two environments have rates that afford
107=109Ag107=109Ag0 P31P2 spin systems [39]. At low temper-
ature the two 31P environments are distinguishable. The
values of the silver–phosphorus coupling constants for
the Ag2L3 systems are, as expected [40], much less than
those found for the Ag2L2 complexes.
Ph2P
PPh2
Ag
[-O2CCF3]2
N
N
OH2
11
0
31
++
H2O
Ag
Ph2P
N
In some cases a signal at ca. 23 ppm is present due to the
oxidised form of the free ligand, suggesting dissociation of
the 3:2 adduct to form a dinuclear 1:1 species and fast oxi-
dation of the free ligand.
Ph2P
PPh2
Ag
[-O2CC3F7]2
N
N
The signals due to the free phosphine L and L0 ligands
are always up-field with respect to those of their corre-
sponding silver(I) complexes. It is worthy of note that the
presence of two or more different doublets having also very
different 31P–Ag coupling constants in the case of com-
pounds 3, 6 and 12 suggests the existence of different spe-
cies in solution. Muetterties and Alegranti [41] and Goel
and Pilon [42] indicated that the spin–spin constant (J)
between phosphorus and silver changes according to the
number of coordinated phosphorus atoms in the silver
complex, and that it is possible to determine the number
of the latter from measurement of the J values in the 31P
NMR spectra. On the basis of the detected values, an
AgPN coordination environment is likely in solution for
compounds 4 and 5, partially consistent with the structure
found for 5 in the solid state; an AgPX2 coordination envi-
ronment is likely for derivatives 1 and 2, whereas the three
different signals found at low temperature in the spectrum
of 6 are consistent with the three different phosphorus
coordination environments found in the solid state. 31P
NMR low-temperature spectra of derivatives 10–12 are
very similar to the spectrum of 8, all showing two different
doublets between 7 and 9 ppm, characterized by small
silver–phosphorus coupling constants. In the spectrum
of 10 there is also a low intensity doublet, for which the
OH2
12
Chart 3.
In compounds 10 and 11 the D is ca. 215 cmꢀ1, consistent
with unidentate coordination of the carboxylate groups.
31P chemical shifts (CDCl3 solution) and 31P–Ag cou-
pling-constants for derivatives 1–13, are reported in Sec-
tion 2. They have been found to be slightly dependent on
the dilution of the solutions, and strongly dependent on
the temperature. Our experiments have been carried out
at a concentration of 0.005 mol/L. The room temperature
31P NMR spectra of complexes 1–7 consist of broad sing-
lets, presumably in consequence of exchange equilibria that
are reasonably fast in relation to the NMR time scale.
Exchange is quenched at low temperature (223 K), and
one and/or two unresolved doublets arising from coupling
between the phosphorus and silver atom are observed in
the accessible temperature range. The observed
1J(107Ag)/1J(109Ag) ratio is in good agreement with that
calculated from the gyromagnetic ratio of the Ag nuclei
c(107Ag)/c(109Ag) [38]. For derivatives 8–12, which in the

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A. Cingolani et al. / Inorganica Chimica Acta 359 (2006) 2183–2193
chemical shift and the coupling constant values suggest a
dinuclear structure as found in the solid state for com-
pounds 4 and 5. On the basis of the similarity found
between the spectra of 6 and 7, a dinuclear structure with
two silver centers bridged by two SCN moieties has been
hypothesised for the former compounds.
Fig. 1. Projections of the dimeric species (a) AgNO2:L (2:2), 5; (b) AgNO2:L0 (2:2), 13; (c) Agdtc:L (2:2), 3; (d) [L2Ag(l-Cl)2AgL(NCMe)], 6; (e) the
[(MeCN)Ag(l-L)3Ag(OH2)]2+ cation of the perchlorate 8.

A. Cingolani et al. / Inorganica Chimica Acta 359 (2006) 2183–2193
2191
Table 2
3.2. X-ray diffraction studies
Silver environment: [(Ph2pyP)2Ag(l-Cl)2Ag(NCMe)(PPh2py)], 6
Atom
Cl(1)
r
Cl(2)
P(1,3)
P/N
A number of the above complexes have been subjected
to single-crystal X-ray characterizations, the results com-
prising the definition of a number of stoichiometric and ste-
reochemical forms, of greater diversity and novelty than
anticipated. All are binuclear, a wide range of Agꢁ ꢁ ꢁAg dis-
tances being found, but the bridging entities are diverse,
being either anion or ligand; the heterocycle component
of the ligand is not always involved in coordination, in
some cases being supplanted by solvent donors, usually
regarded as being of lesser donor capacity, despite the
ostensible lack of strain inherent in the heterocycle bridging
capability. A contemporaneous relevant review is noted
[43].
The ligand is found in purely terminal P-donor mode in
two of the complexes. In Agdtc: PPh2py (1:1)2, 3, (Fig. 1
and Table 1), centrosymmetric, one Agdtc: PPh2py unit,
devoid of crystallographic symmetry comprises the asym-
metric unit of the structure. The independent silver atom
is chelated by the S,S0-dithiocarbamate anion. Ag–S(1) is
shorter than Ag–S(2), by virtue of the latter bridging to
the inversion related counterpart. The silver atom lies well
out of the S2CNC2 ligand plane, the latter forming a dihe-
dral angle of 78.26(8)ꢁ to the Ag(l-S(2))2Ag core plane,
Ag(l-dtc)2Ag forms of this type being previously estab-
lished [44]. The coordination sphere is completed by the
terminal/unidentate PPh2py ligand, the pyridine nitrogen
directed away from the metal but without any significantly
close interdimer contact.
With triphenylphosphine as ligand, binuclear forms are
found with the copper(I) halides of stoichiometry CuX
(X = Cl, Br, I):PPh3 (2:3), it being surmised that 2:4 stoi-
chiometry is not achieved because of steric difficulties
imposed about the molecular core by ligand crowding;
by contrast, binuclear [(Ph3P)2Ag(l-X)2Ag(Ph3P)2] has
been recorded with the larger metal/silver atom [45]. Here,
it is of interest to find that with the relatively small halide,
2:4 stoichiometry is not achieved, but, rather, an acetoni-
trile coordinates instead of one of the putative ligands
yielding [(Ph2pyP)2Ag(l-Cl)2Ag(PPh2py)(NCMe)], (Fig. 1
and Table 2), despite its limited donor capacity vis-a-vis
excess phosphine or intra- or inter-dimer bridging pyridyl
2.7102(7)
2.4994(8)
87.73(2)
94.40(2)
104.67(2)
142.32(3)
109.88(2)
82.98(7)
Cl(2)
2.6523(7)
2.5654(8)
116.63(2)
121.98(3)
104.04(4)
122.00(8)
P(1,3)
2.4459(6)
2.3765(8)
Ag(1)ꢁ ꢁ ꢁAg(2)
126.85(2)
85.19(7)
˚
3.6416(3) A
˚
Cl(1)ꢁ ꢁ ꢁCl(2) 3.716(1) A
P(2)
N(01)
2.4558(8)
3.209(3)
Presentation as for Table 1; values for Ag(2) lie below those for Ag(1).
s (Ag–P(n)–C(n1)–N,C(n2) for the three ligands (n = 1;2;3) are: ꢀ58.8(3),
ꢀ18.8(2), ꢀ35.9(3); 178.2(2), 33.9(2), 27.6(2); ꢀ43.1(3), ꢀ46.2(2),
ꢀ35.9(3)ꢁ.
groups; the full formula unit comprises the asymmetric
unit of the structure. Ag-NCMe is long (3.209(3) A, cf.
values ca. 2.25 A recorded for [Ag(NCMe)4](ClO4) [46],
with MeCN inclined towards parallelism with the nearby
associated Ag–Cl core linkage; the angle sum within the
PAg(l-Cl)2 complement in the rest of the Ag(2) coordina-
tion sphere is 358.7ꢁ, suggesting a description as quasi-
[(Ph2pyP)2Ag(l-Cl)2Ag(PPh2py)] (solvated) not to be
inappropriate.
˚
˚
Such an array is an extension of the extant series of
AgCl:PPh2py adducts – the 1:1 adduct takes the form of
the usual ‘cubane’ tetramer [Ag4Cl4L4], L bound only
through the phosphorus [47], while an adduct of 2:3 stoi-
chiometry (unsolvated) takes the form [LAg(l-
Cl)2(lꢀN,(L),P)AgL], wherein Agꢁ ꢁ ꢁAg0 is 3.074 A, cf.
˚
˚
the present 3.6416(3) A, the pyridyl donor bridging to
occupy the site presently occupied by the acetonitrile [48].
The two adducts of silver nitrite with L and L0 ligands,
5, 13, both take the same form, being centrosymmetric
dimers of (1:1)2 stoichiometry (Fig. 1 and Table 3), the
two silvers being bridged by the P and N functionalities
of a pair of ligands, the anion, of small bite, chelating the
metal atoms in both cases, with the AgO2N ‘plane’ quasi-
normal to the resulting metallacycle ‘plane’. Despite the
formal similarity of the two dimers, and the centrosymmet-
ric nature of the metallacycles, the latter differ between the
two complexes, in respect of their conformations, very con-
siderably - ring torsions in the Ag–N–C–P–Ag strings are
70.9(1), 1.6(1), 73.2(1), ꢀ113.06(6) (the PPh2py complex),
ꢀ84.9(2), ꢀ16.6(1), ꢀ10.3(2), 79.7(2)ꢁ (the L = PPh2bim
complex) so that the resulting Agꢁ ꢁ ꢁAg distances are very
different. Residues modelled plausibly as lattice methanol
(no OH hydrogen located) may be hydrogen-bonded to
Table 1
The silver environment: Agdtc:L (1:1)2, 3
Atom
r
S(1)
S(2)
S(201)
P
2.381(1)
2.563(1)
2.797(1)
2.531(1)
121.31(4)
111.46(4)
65.99(5)
123.13(4)
106.58(4)
115.05(4)
S(1)
S(2)
S(20)
˚
the nitrite (O(01)ꢁ ꢁ ꢁO(2) (1ꢀx, 1ꢀy, 1ꢀz) 2.874(5) A) and
0
˚
Agꢁ ꢁ ꢁAg 2.8696(8) A
˚
each other (O(01)ꢁ ꢁ ꢁO(02) (x; y; z; 2 ꢀ x;ꢀz; 1 ꢀ z) 2.99(1) A
˚
r A is the silver-ligand atom distance; other entries in the matrix are the
angles subtended by the relevant atoms at the head of the row and column.
Ag–S(1)–C(1) is 89.5(2); Ag,Ag0–S(2)–C(1) are 81.2(2), 102.5(2) with Ag–
(x2)) (see Table 4).
In the final compound, of AgX:L (1:1.5)2 stoichiometry,
8, the anion, being perchlorate, is uncoordinated, and, the
coordinating capabilities of the PPh2py ligands being fully
utilized, a solvated cation is formed, the array being
S(2)–Ag0 64.95(3); S(1)–C(1)–S(2) is 120.1(3)ꢁ. Ag,Ag0 lie ꢀ0.933(5),
2
˚
˚
1.627(4) A out of the S2CNC2 ‘plane’ (v 722); Ag lies 0.10(1) A out of the
py (C5N) plane. s (Ag–P–C(n1)–N,C(n2)) are ꢀ177.3(4), ꢀ33.2(5), 0.6(4)ꢁ.

2192
A. Cingolani et al. / Inorganica Chimica Acta 359 (2006) 2183–2193
Table 3
vated precursor, namely AgClO4:L (2:3) which in the solid
state takes the form [LAg(l-N(L)P)2](ClO4)2, wherein two
of the l0igands are bridging and one P-terminal, with
The silver environments: AgNO2:X (2:2) (X = L, L0), 5, 13
Atom
P
r
N(120)
O(1)
O(2)
˚
Agꢁ ꢁ ꢁAg 3.072 A [49].
2.3907(4)
2.3817(5)
117.20(3)
156.94(6)
119.63(6)
111.25(6)
128.48(5)
99.12(5)
N(120)
O(1)
2.350(2)
2.223(2)
121.24(7)
91.21(8)
85.43(6)
91.58(7)
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0
˚
2.341(2)
2.481(4)
Agꢁ ꢁ ꢁAg 4.0650(2) A
50.55(6)
49.17(9)
3.1052(3)
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2.542(2)
2.557(3)
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Presentation as for Table 1. Values for the L0 = PPh2im complex lie below
those for the L = PPh2py complex. Primed atoms are centrosymmetrically
related.
In the L;L0 complexes, N–O(1,2), Ag–O(1,2)-N, O(1)–N–O(2) are:
˚
˚
1.258(3), 1.235(2) A, 102.3(1), 93.0(1), 114.2(2)ꢁ; 1.254(2), 1.237(5) A,
˚
99.7(2), 96.4(2), 114.7(3)ꢁ, Ag lying 0.048(9); 0.16(1) A out of the NO2
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˚
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Silver environments in [(MeCN)Ag(l-L)3Ag(OH2)](ClO4)2, 8
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Atom
r
P(3)
N(212)
N(11)
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P(1)
P(3)
N(212)
N(11)
2.4528(8)
2.5260(9)
2.360(3)
2.452(3)
114.68(3)
139.24(7)
99.53(6)
96.84(7)
110.17(8)
91.1(1)
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˚
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Atom
r
N(112)
N(312)
O(2)
(b) Ag(2)
P(2)
N(112)
N(312)
O(2)
2.3805(9)
2.393(2)
2.267(3)
2.559(3)
110.62(7)
149.13(6)
98.16(9)
104.88(7)
85.75(9)
87.68(10)
Ag(2)–P(2)–C(211) is 120.4(1); Ag(2)–N(112,312)–C(11,311) are 123.8(2),
122.3(2)ꢁ. s(Ag(2)–P(2)–C(211)–N,C(212)) are ꢀ42.9(3), ꢀ70.5(3),
˚
ꢀ25.8(3)ꢁ. Ag(2) lies 0.333(5), 0.321(5) A out of (C5N) pyridyl planes 1,3.

A. Cingolani et al. / Inorganica Chimica Acta 359 (2006) 2183–2193
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