Variable coordination modes of NO2- in a series of Ag(I) complexes containing triorganophosphines, -arsines, and -stibines. Syntheses, spectroscopic characterization (IR, 1H and 31P NMR, electrospray ionization mass), and structures of [AgNO2(R3E)x] adducts (E = P, As, Sb, x = 1-3)

Article abstract of DOI:10.1021/ic020375g

Adducts of triorganophosphine, triphenylarsine, and triphenylstibine with silver(I) nitrite have been synthesized and characterized both in solution ¹H, ³¹P NMR) and in the solid state (IR, single-crystal X-ray structure analysis). In addition aggregates of AgNO₂ and ER₃ (E = P, As, Sb) have been identified in solution by electrospray ionization mass spectrometry (ESI-MS). The topology of the structures in the solid state was found to depend on the nature of ER3 and on the stoichiometric ratio AgNO₂:ER3. The adducts AgNO₂:EPh₃ (1:1) (E = P or Sb) are one-dimensional polymers, the role of NO₂^- being to bridge successive metal atoms by coordination of the two oxygens to one silver atom and the nitrogen lone pair to a successive Ag. The adduct AgNO₂:P(o-tolyl)₃ (1:1) is mononuclear, due to steric hindrance of the phosphine, the nitrite being O,O′-bidentate, a rare example of a quasi-linear P-Ag-X array. AgNO₂:P(p-F-C₆H₄)₃ (1:1) is a dimer, the nitrite being coordinated through both oxygens, the first unidentate, the second bridging bidentate. P(o-tolyl)₃ and Pcy₃ form 1:2 adducts, also mononuclear, the nitrite still an O,O′chelate. In contrast, the adduct AgNO₂:AsPh₃ (1:2) is a centrosymmetric dimer, essentially an aggregate of a pair of [Ag(O₂N)(AsPh₃)₂] arrays with one nitrite oxygen being the bridging atom. The adducts AgNO₂:EPh₃ (1:3) (E = As, Sb) are mononuclear, the nitrite behaving as a consistently strong O,O′-chelate. The E = As adduct is a triclinic solvated form, whereas the unsolvated E = Sb species is monoclinic. ESI-MS spectra of acetonitrile solutions of these complexes show the existence of [Ag(ER₃)]⁺, [Ag(CH₃CN)]⁺, [Ag(CH₃CN)₂]⁺, [AgCl₂]^-, [Ag(NO₂)₂]^-, [Ag(ER₃)(CH₃CN)]⁺, and [Ag(ER₃)₂]⁺ as well as higher aggregates [Ag₂(NO₂)(ER₃)₂]⁺, [Ag₂(NO₂)₃]^- and [Ag₂Cl₂(NO₂)]^- which are less prevalent.

Full text of DOI:10.1021/ic020375g

Inorg. Chem. 2002, 41, 6633−6645
Variable Coordination Modes of NO - in a Series of Ag(I) Complexes
2
Containing Triorganophosphines, -arsines, and -stibines. Syntheses,
Spectroscopic Characterization (IR, 1H and 31P NMR, Electrospray
Ionization Mass), and Structures of [AgNO (R E)x] Adducts (E ) P, As,
2
3
Sb, x ) 1−3)
,†
Augusto Cingolani,† Effendy,‡,§ Maura Pellei,† Claudio Pettinari,* Carlo Santini,†
Brian W. Skelton,§ and Allan H. White§
Dipartimento di Scienze Chimiche, UniVersita` degli Studi di Camerino, Via S. Agostino 1,
62032 Camerino MC, Italy; Jurusan Kimia, FMIPA UniVersitas Negeri Malang,
Jalan Surabaya 6, Malang, Indonesia 65145, and Department of Chemistry, The UniVersity of
Western Australia, Crawley, Western Australia 6009
Received May 30, 2002
Adducts of triorganophosphine, triphenylarsine, and triphenylstibine with silver(I) nitrite have been synthesized and
characterized both in solution (1H, 31P NMR) and in the solid state (IR, single-crystal X-ray structure analysis). In
addition aggregates of AgNO and ER (E ) P, As, Sb) have been identified in solution by electrospray ionization
2
3
mass spectrometry (ESI-MS). The topology of the structures in the solid state was found to depend on the nature
of ER and on the stoichiometric ratio AgNO :ER . The adducts AgNO :EPh3 (1:1) (E ) P or Sb) are one-dimensional
3
2
3
2
polymers, the role of NO - being to bridge successive metal atoms by coordination of the two oxygens to one
2
silver atom and the nitrogen lone pair to a successive Ag. The adduct AgNO :P(o-tolyl)3 (1:1) is mononuclear, due
2
to steric hindrance of the phosphine, the nitrite being O,O′-bidentate, a rare example of a quasi-linear P−Ag−X
array. AgNO :P(p-F−C H ) (1:1) is a dimer, the nitrite being coordinated through both oxygens, the first unidentate,
2
6 4 3
the second bridging bidentate. P(o-tolyl)3 and Pcy3 form 1:2 adducts, also mononuclear, the nitrite still an O,O′-
chelate. In contrast, the adduct AgNO :AsPh3 (1:2) is a centrosymmetric dimer, essentially an aggregate of a pair
2
of [Ag(O N)(AsPh3)2] arrays with one nitrite oxygen being the bridging atom. The adducts AgNO :EPh3 (1:3) (E )
2
2
As, Sb) are mononuclear, the nitrite behaving as a consistently strong O,O′-chelate. The E ) As adduct is a
triclinic solvated form, whereas the unsolvated E ) Sb species is monoclinic. ESI-MS spectra of acetonitrile solutions
of these complexes show the existence of [Ag(ER )]+, [Ag(CH CN)]+, [Ag(CH CN)2]+, [AgCl2]-, [Ag(NO ) ]-,
3
3
3
2 2
[Ag(ER )(CH CN)]+, and [Ag(ER ) ]+ as well as higher aggregates [Ag (NO )(ER ) ]+, [Ag (NO ) ]- and [Ag Cl2(NO )]-,
3
3
3 2
2
2
3 2
2
2 3
2
2
which are less prevalent.
-
Introduction
Coordination of NO2 to a metal can also provide
important information for the understanding of chemical
reactions in the atmosphere involving pollutants such as
nitrogen oxides (NOx, x ) 1 or 2) and of corrosion processes.
-
NO2 -containing coordination compounds have been
extensively studied, being of interest because of the ability
-
of NO2 to coordinate a metal in a number of different
-
The interaction of the NO2 ligand with alkaline,2-6
bonding modes (Figure 1), e.g. yielding nitro compounds
M-NO2 as N-donor or nitrito derivatives M-O-NO as
O-donor.1 Each NO2 coordination mode leads to different
properties for the compound.
alkaline earth,7-10 and transition metal species11-15 has been
widely studied by several authors both theoretically and
experimentally, whereas only a few examples of nitrite
coordination to silver centers have been reported.
* To whom correspondence should be addressed. Fax: 0039 0737
637345. E-mail: claudio.pettinari@unicam.it.
† Universita` di Camerino.
(1) See for example: (a) Veillard, A. Chem. ReV. 1991, 91, 743-766.
(b) Organometallic Ion Chemistry; Freiser, B. S., Ed.; Kluwer
Academic Publishers: Dordrecht, The Netherlands, 1996.
‡ FMIPA Universitas Negeri Malang.
§ University of Western Australia.
10.1021/ic020375g CCC: $22.00 © 2002 American Chemical Society
Published on Web 11/13/2002
Inorganic Chemistry, Vol. 41, No. 25, 2002 6633

Cingolani et al.
modes of the anions. By comparison the chemistry of tertiary
stibines and arsines has only been investigated sparsely,
though again there has been increased interest recently.23,24
Here we report the synthesis and spectroscopic charac-
terization of 16 novel AgNO2:ER3 adducts supported by 10
single-crystal X-ray studies to assist in understanding the
relationships between molecular packing, coordinating ability
-
of NO2 , donor capacity, and the Tolman cone angle of the
ancilliary ligand. Our results demonstrate that remarkably
stable neutral silver complexes showing different silver(I)
coordination environments and NO2- coordination modes can
be easily synthesized: oxygen-bridged one-dimensional
polymers, mononuclear forms with nitrite O,O′-bidentate
containing one, two, or three ancillary donors, and binuclear
and polymeric aggregates in which nitrite oxygen atoms are
the bridging atoms.
Recent advances in electrospray ionization mass spec-
trometry (ESI-MS) have provided an especially powerful tool
for observing in the gas phase the solution composition of
charged species.25 The (ESI-MS) technique has been very
successfully applied to problems in biochemistry26 and in
the speciation of inorganic and organometallic complexes
of various metals, including Ag, Pd, Zn, and others.27 The
existence in solution of our complexes has been probed by
(ESI-MS) in acetonitrile and in some cases also in acetone.
Aggregates of the phosphine, arsine, and stibine ligands and
Ag(I)NO2 are observed in both solvents, but the aggregation
is diminished in acetonitrile due to predominance of solvent
coordination to silver(I).
-
Figure 1. Some possible coordination modes for the NO2 ligand.
A silver(I) nitrite (di-2-pyridyl ketone) complex, stabilized
by intramolecular π stacking interactions and aligned into
chains through the intermolecular π stacking interactions in
a zipper-like fashion, has been recorded by Yang and co-
workers.16 AgNO2 reacts with hexamethylenetetramine in
MeCN-H2O to yield a two-dimensional coordination poly-
mer with square cavities.17 The reaction of Ag(I) salts with
1,4-dithiane has produced several interesting coordination
polymers, the structures of which vary significantly with the
-
anion. In particular, when NO2 acts as the anion, the
interlinked chains give a 3-D diamondoid network.18
In this paper we describe a series of AgNO2 adducts with
unidentate triorganophosphines, -arsines, and -stibines EPh3
(E ) P, As, Sb), P(o-tolyl)3, P(m-tolyl)3, P(p-tolyl)3, P(p-
F-C6H4)3, and Pcy3. The coordination chemistry of tertiary
phosphine adducts provides a well-established basis permit-
ting systematic investigation of the possible coordination
Experimental Section
Materials and Methods. All reactions were carried out under
an atmosphere of dry oxygen-free dinitrogen, using standard
Schlenk techniques and protected from light. Solvents were used
as supplied or distilled using standard methods. All chemicals were
purchased from Aldrich (Milwaukee) and used as received.
Elemental analyses (C, H, N, S) were performed with a Fisons
Instruments 1108 CHNS-O elemental analyzer. IR spectra were
recorded from 4000 to 100 cm-1 with a Perkin-Elmer System 2000
-
-
modes of oxyanions such as NO3 and ClO4 to Ag(I)19-21
and Cu(I) ions,22 with interesting structural variations within
the series MX:(PR3)n resulting from the different coordination
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Struct. (THEOCHEM) 1992, 253, 121-147.
(6) Lo, W.-J.; Shen, M.-Y.; Yu, C.-H.; Lee, Y.-P. J. Chem. Phys. 1996,
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(7) Herm, R. R.; Lin, S. M.; Mims, C. A. J. Phys. Chem. 1973, 77, 2931-
2937.
1
FT-IR instrument. H and 31P NMR spectra were recorded on a
VXR-300 Varian spectrometer operating at room temperature (300
1
MHz for H, and 121.4 MHz for 31P). Proton chemical shifts are
reported in parts per million vs Me4Si, while phosphorus chemical
(8) Davis, H. F.; Suits, A. G.; Lee, Y. T. J. Chem. Phys. 1992, 96, 6710-
6726.
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Dalton Trans. 1985, 321-331.
(9) Cheong, B. S.; Parson, J. M. J. Chem. Phys. 1994, 100, 2637-2650.
(10) Rodriguez-Santiago, L.; Sodupe, M.; Branchadell, V. J. Phys. Chem.
1998, 102, 630-635.
(21) Bowmaker, G. A.; Effendy; Skelton, B. W.; White, A. H. J. Chem.
Soc., Dalton Trans. 1998, 2123-2129.
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1994, 90, 2003-2007.
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G.; Colapietro, M. Inorg. Chim. Acta 1996, 249, 215-229. (b)
Cingolani, A.; Effendy; Marchetti, F.; Pettinari, C.; Skelton, B. W.;
White, A. H. J. Chem. Soc., Dalton. Trans. 1999, 4047-4055.
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Aust. J. Chem. 1997, 50, 653-670 (corrigendum: Bowmaker, G. A.;
Effendy; Hart, R. D.; Kildea, J. D.; White, A. H. Aust. J. Chem. 1998,
51, 90).
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1995, 103, 9738-9743.
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1996, 105, 9966-9971.
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V. Inorg. Chem. 1998, 37, 4512-4517.
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545, 111-115.
(16) Yang, G.; Zheng, S. L.; Chen, X. M.; Lee, H. K.; Zhou, Z. Y.; Mak,
T. C. W. Inorg. Chim. Acta 2000, 303, 86-93.
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(25) (a) Hop, C. E. C. A.; Bakhtiar, R. J. Chem. Educ. 1996, 73, A162-
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6634 Inorganic Chemistry, Vol. 41, No. 25, 2002

-
Variable Coordination Modes of NO2
shifts are reported in parts per million vs 85% H3PO4. The electrical
conductances of the CH2Cl2 solutions were measured with a Crison
CDTM 522 conductimeter at room temperature. The positive and
negative electrospray mass spectra were obtained with a Series 1100
MSI detector HP spectrometer, using an acetonitrile mobile phase.
Solutions (3 mg/mL) for electrospray ionization mass spectrometry
(ESI-MS) were prepared using reagent grade acetone or acetonitrile.
For the ESI-MS data, mass and intensities were compared to those
calculated using IsoPro Isotopic Abundance Simulator vers. 2.1.28
Peaks containing silver(I) ions are identified as the center of an
isotopic cluster.
1H NMR (CDCl3, 293 K): δ 7.25-7.41 (m, 60H, C6H5). 31P{1H}
NMR (CDCl3, 293 K): δ 4.7 (s). 31P{1H} NMR (CDCl3, 218 K):
δ 5.6 (d, 1J(31P-Ag) ) 228 Hz), 32.2 (s). Λmol (CH2Cl2, concn )
1.00 × 10-3 M): 1.1 Ω-1 cm2 mol-1. ESI MS (MeCN): (+) 632
(100) [Ag(PPh3)2]+, 786 (2) [Ag2(NO2)(PPh3)2]+. Anal. Calcd for
C72H60AgNO2P4: C, 71.88; H, 5.03; N, 1.16. Found: C, 71.65; H,
5.22; N, 1.24.
[AgNO2{P(o-tolyl)3}] (5). AgNO2 (0.154 g, 1 mmol) was added
to an ethanol solution (30 mL) of P(o-tolyl)3 (0.304 g, 1 mmol) at
60 °C. After the addition, the solution was stirred for 24 h at
60 °C and then concentrated with a rotary evaporator and stored at
4 °C for 3 days. A colorless precipitate was formed, which was
filtered off and washed with ethanol (3 × 5 mL) and shown to be
compound 5 and recrystallized from ethanol. Yield: 60%. Mp:
189-190 °C. IR (Nujol, cm-1) data: 3048w, ν(C-H); 1456s,
1306br, ν(NO2); 850vw, δ(ONO); 565m, 560sh, 524w, 515sh, 467s,
[AgNO2(PPh3)] (1). Silver(I) nitrite (0.154 g, 1 mmol) was added
to an ethanol solution (30 mL) of PPh3 (0.262 g, 1 mmol) at 60
°C. After the addition, the solution was stirred for 24 h at 60 °C.
A colorless precipitate was formed which was filtered off and
washed with ethanol (3 × 5 mL). Recrystallization from ethanol
gave complex 1 as a microcrystalline solid in 59% yield. Mp: 162-
165 °C. IR (Nujol, cm-1) data: 3170w, ν(C-H); 1435s, 1336vw,
1217br, ν(NO2); 838w, δ(ONO); 523s, 501m, 489s, 437m, δ(PPh3).
1H NMR (CDCl3, 293 K): δ 7.35-7.55 (m, 15H, C6H5). 31P{1H}
NMR (CDCl3, 293 K): δ 16.5 (d br, 1J(31P-Ag) ) 621 Hz). 31P-
{1H} NMR (CDCl3, 218 K): δ 16.1 (dd,1J(31P-107Ag) ) 666 Hz,
1J(31P-109Ag) ) 769 Hz). Λmol (CH2Cl2, concn ) 1.00 × 10-3
M): 0.1 Ω-1 cm2 mol-1. ESI MS (MeCN): (+) 189 (5) [Ag-
(MeCN)2]+, 411 (80) [Ag(MeCN)(PPh3)]+, 632 (100) [Ag(PPh3)2]+,
786 (30) [Ag2(NO2)(PPh3)2]+; (-) 178 (18) [AgCl2]-, 199 (100)
[Ag(NO2)2]-, 332 (65) [Ag2Cl2NO2]-. Anal. Calcd for C18H15-
AgNO2P: C, 51.95; H, 3.63; N, 3.37. Found: C, 51.78; H, 3.72;
N, 3.40.
1
446sh, δ(PAr3). H NMR (CDCl3, 293 K): δ 2.50 (s, 9H, CH3),
6.81, 7.17, 7.33, 7.43 (t, 12H, C6H4). 1H NMR (CDCl3, 293 K): δ
2.50 (s, 9H, CH3), 6.74, 7.18, 7.34, 7.45 (tbr, 12H, C6H4). 31P{1H}
NMR (CDCl3, 293 K): δ -17.7 (d br). 31P{1H} NMR (CDCl3,
223 K): δ -19.2 (d, 1J(31P-Ag) ) 695 Hz). Λmol (CH2Cl2,
concn ) 1.10 × 10-3 M): 0.05 Ω-1 cm2 mol-1. ESI MS (MeCN):
(+) 452 (30) [Ag(MeCN)(P(o-tolyl)3)]+, 716 (100) [Ag(P(o-
tolyl)3)2]+, 870 (30) [Ag2(NO2)(P(o-tolyl)3)2]+; (-) 178 (15)
[AgCl2]-, 199 (100) [Ag(NO2)2]-, 332 (60) [Ag2Cl2NO2]-. Anal.
Calcd for C21H21AgNO2P: C, 55.04; H, 4.62; N, 3.06. Found: C,
55.13; H, 4.82; N, 3.20.
[AgNO2{P(o-tolyl)3}2] (6). Compound 6 was prepared similarly
to 5, by using AgNO2 (0.154 g, 1 mmol) and P(o-tolyl)3 (0.609 g,
2 mmol). Compound 6 was recrystallized from ethanol. Yield: 42%.
Mp: 193-195 °C. IR (Nujol, cm-1) data: 3050w, ν(C-H); 1226w,
ν(NO2); 828w, δ(ONO); 564sh, 558s, 552sh, 529s, 475s, 459s,
[AgNO2(PPh3)2] (2). Compound 2 has been synthesized similarly
to 1, by using AgNO2 (0.154 g, 1 mmol) and PPh3 (0.525 g, 2
mmol). Compound 2 was recrystallized from ethanol. Yield: 80%.
Mp: 203-205 °C. IR (Nujol, cm-1) data: 3068vw, ν(C-H); 1433s,
1326vw, 1225br, ν(NO2); 832w, δ(ONO); 511sh, 495s, 438m,
1
δ(Ph3P). H NMR (CDCl3, 293 K): δ 2.34 (s, 18H, CH3), 6.81,
7.10, 7.24, 7.34 (pt, 24H, C6H4). 1H NMR (CDCl3, 223 K): δ 2.11
(s, 18H, CH3), 6.84, 7.07, 7.20, 7.35 (pt br, 24H, C6H4). 31P{1H}
NMR (CDCl3, 293 K): δ -19.0 (s). 31P{1H} NMR (CDCl3, 223
K): δ -11.0 (br). Λmol (CH2Cl2, concn ) 1.00 × 10-3 M): 0.2
Ω-1 cm2 mol-1. ESI MS (MeCN): (+) 716 (100) [Ag(P(o-
tolyl)3)2]+, 870 (5) [Ag2(NO2)(P(o-tolyl)3)2]+. Anal. Calcd for
C42H42AgNO2P2: C, 66.15; H, 5.55; N, 1.84. Found: C, 66.11; H,
5.68; N, 1.92.
1
422w, δ(Ph3P). H NMR (CDCl3, 293 K): 7.20-7.42 (m, 30H,
C6H5). 31P{1H} NMR (CDCl3, 293 K): δ 9.3 (s). 31P{1H} NMR
1
1
(CDCl3, 218 K): δ 8.95 (dd, J(31P-107Ag) ) 413 Hz, J(31P-
109Ag) ) 476 Hz). Λmol (CH2Cl2, concn ) 1.05 × 10-3 M): 0.2
Ω-1 cm2 mol-1. ESI MS (MeCN): (+) 411 (10) [Ag(MeCN)-
(PPh3)]+, 632 (100) [Ag(PPh3)2]+, 786 (5) [Ag2(NO2)(PPh3)2]+.
Anal. Calcd for C36H30AgNO2P2: C, 63.73; H, 4.46; N, 2.06.
Found: C, 64.03; H, 4.64; N, 2.01.
[AgNO2{P(m-tolyl)3}] (7). Compound 7 was prepared similarly
to 5, by using AgNO2 (0.154 g, 1 mmol) and P(m-tolyl)3 (0.304 g,
1 mmol). Compound 7 was recrystallized from ethanol. Yield: 46%.
Mp: 140-145 °C. IR (Nujol, cm-1) data: 3169w, ν(C-H); 1225w,
ν(NO2); 832m δ(ONO); 544m, 558s, 521vw, 462s, 446m, 430vw,
δ(Ph3P). 1H NMR (CDCl3, 293 K): δ 2.19 (s, 9H, CH3), 7.08 (br,
3H, C6H4), 7.17 (pd, 9H, C6H4). 31P{1H} NMR (CDCl3, 293 K):
[AgNO2(PPh3)3] (3). Compound 3 was prepared similarly to
compound 1, by using AgNO2 (0.154 g, 1 mmol) and PPh3 (0.787
g, 3 mmol). Compound 3 was recrystallized from ethanol. Yield:
85%. Mp: 216-220 °C. IR (Nujol, cm-1) data: 3167vw, ν(C-
H); 1434s, 1377w, 1183br, ν(NO2); 848vw, δ(ONO); 501s, 492s,
1
438m, 419m, δ(Ph3P). H NMR (CDCl3, 293 K): δ 7.20-7.40
1
δ 10.5 (br). 31P{1H} NMR (CDCl3, 218 K): δ 10.0 (d, J(31P-
(m, 45H, C6H5). 31P{1H} NMR (CDCl3, 293 K): δ 5.2 (s). 31P-
Ag) ) 660 Hz). Λmol (CH2Cl2, concn ) 1.05 × 10-3 M): 1.4 Ω-1
cm2 mol-1. ESI MS (MeCN): (+) 716 (100) [Ag(P(m-tolyl)3)2]+,
870 (3) [Ag2(NO2)(P(m-tolyl)3)2]+. Anal. Calcd for C21H21-
AgNO2P: C, 55.04; H, 4.62; N, 3.06. Found: C, 55.14; H, 4.51;
N, 3.12.
1
{1H} NMR (CDCl3, 218 K): δ 5.6 (d, J(31P-Ag) ) 228 Hz),
32.2 (s). Λmol (CH2Cl2, concn ) 1.20 × 10-3 M): Λ 1.4 Ω-1 cm2
mol-1. ESI MS (MeCN): (+) 632 (100) [Ag(PPh3)2]+, 786 (5)
[Ag2(NO2)(PPh3)2]+. Anal. Calcd for C54H45AgNO2P3: C, 68.94;
H, 4.82; N, 1.49. Found: C, 68.68; H, 5.01; N, 1.56.
[AgNO2{P(m-tolyl)3}2] (8). Compound 8 was prepared similarly
to 5, by using AgNO2 (0.154 g, 1 mmol) and P(m-tolyl)3 (0.609 g,
2 mmol), and recrystallized from ethanol. Yield: 52%. Mp: 180-
183 °C. IR (Nujol, cm-1) data: 3047w, ν(C-H); 1401m, 1276vw,
1124s, ν(NO2); 830w, δ(ONO); 544m, 521vw, 462s, 446m, 430vw,
[AgNO2(PPh3)4] (4). Compound 4 was prepared similarly to
compound 1, by using AgNO2 (0.154 g, 1 mmol) and PPh3 (1.311
g, 3 mmol) and recrystallized from ethanol (yield 56%). Mp: 166-
167 °C. IR (Nujol, cm-1) data: 3052w, ν(C-H); 1434s, 1309vw,
1184br, ν(NO2); 819vw, δ(ONO); 512s, 503s, 494s, 438m, δ(Ph3P).
1
δ(Ph3P). H NMR (CDCl3, 293 K): δ 2.16 (s, 18H, CH3), 7.04
1
(br, 6H, C6H4), 7.15 (pd, 18H, C6H4). H NMR (CDCl3, 218 K):
(28) Senko, M. W. IsoPro Isotopic Abundance Simulator, v. 2.1; National
High Magnetic Field Laboratory, Los Alamos National Laboratory:
Los Alamos, NM.
δ 2.12 (s, 18H, CH3), 6.97, 7.07 (br, 12H, C6H4), 7.17 (pd, 12H,
C6H4). 31P{1H} NMR (CDCl3, 293 K): δ 9.5 (sbr), 29.9 (s). 31P-
Inorganic Chemistry, Vol. 41, No. 25, 2002 6635

Cingolani et al.
1
{1H} NMR (CDCl3, 218 K): 8.8 (dd, J(31P,107Ag) ) 411 Hz,
Mp: 166-167 °C. IR (Nujol, cm-1) data: 3050w, ν(C-H); 1481m,
1255br, 1182vw, ν(NO2); 842w, δ(ONO); 473s, 463s, 326s, δ(Ph3-
As). H NMR (CDCl3, 293 K): δ 7.24-7.73 (mc, 35H, C6H5).
1J(31P,109Ag) ) 475 Hz), 32.2 (s). Λmol (CH2Cl2, concn ) 1.20 ×
10-3 M): 0.6 Ω-1 cm2 mol-1. ESI MS (MeCN): (+) 716 (100)
[Ag(P(m-tolyl)3)2]+; (-) 178 (10) [AgCl2]-, 199 (100) [Ag(NO2)2]-.
Anal. Calcd for C42H42AgNO2P2: C, 66.15; H, 5.55; N, 1.84.
Found: C, 65.84; H, 5.74; N, 1.81.
[AgNO2{P(m-tolyl)3}3] (9). Compound 9 was prepared similarly
to 5, by using AgNO2 (0.154 g, 1 mmol) and P(m-tolyl)3 (0.913 g,
3 mmol), and recrystallized from ethanol. Yield: 64%. Mp: 121-
124 °C. IR (Nujol, cm-1) data: 3338w, 3156w, ν(C-H); 1170m,
1104m, ν(NO2); 887m, 770s, δ(ONO); 543s, 534s, 518m, 446s,
423m, δ(Ph3P).1H NMR (CDCl3, 293 K): δ 2.19 (s, 27H, CH3),
1
Λmol (CH2Cl2, concn ) 1.00 × 10-3 M): 0.02 Ω-1 cm2 mol-1
.
ESI MS (MeCN): (+) 189 (5) [Ag(MeCN)2]+, 455 (60) [Ag-
(MeCN)(AsPh3)]+, 719 (100) [Ag(AsPh3)2]+, 874 (80) [Ag2(NO2)-
(AsPh3)2]+; (-) 178 (5) [AgCl2]-, 199 (100) [Ag(NO2)2]-, 332 (55)
[Ag2Cl2NO2]-. Anal. Calcd for C36H30AgAs2NO2: C, 56.42; H,
3.95; N, 1.83. Found: C, 56.71; H, 3.86; N, 2.01.
[AgNO2(AsPh3)3] (14). Compound 14 was prepared similarly
to 1, by using AgNO2 (0.154 g, 1 mmol) and AsPh3 (0.919 g, 3.0
mmol), and recrystallized from ethanol. Yield: 97%. Mp: 182-
184 °C. IR (Nujol, cm-1) data: 3147w, ν(C-H); 1434s, 1214br,
1182w, ν(NO2); 848w, δ(ONO); 478m, 462m, 322s, 312s, δ(Ph3-
1
7.04 (m, 9H, C6H4), 7.15 (m, 27H, C6H4). H NMR (CDCl3, 218
K): δ 1.85, 2.03 (sbr, 27H, CH3), 6.58, 6.68, 6.91, 7.07 (sbr, 36H,
C6H4). 31P{1H} NMR (CDCl3, 293 K): δ 4.9 (s), 29.9 (s). 31P{1H}
1
As). H NMR (CDCl3, 293 K): δ 7.24-7.42 (mc, 45H, C6H5).
NMR (CDCl3, 218 K): 5.1 (d, J(31P, Ag) ) 239 Hz), 10.4 (sbr),
1
Λ
mol (CH2Cl2, concn ) 1.00 × 10-3 M): 0.4 Ω-1 cm2 mol-1. ESI
32.3 (s). Λmol (CH2Cl2, concn ) 1.10 × 10-3 M): 1.1 Ω-1 cm2
mol-1. ESI MS (MeCN): (+) 716 (100) [Ag(P(m-tolyl)3)2]+. Anal.
Calcd for C63H63AgNO2P3: C, 70.92; H, 5.95; N, 1.31. Found: C,
70.65; H, 6.25; N, 1.34.
MS (MeCN): (+) 719 (100) [Ag(AsPh3)2]+, 874 (80) [Ag2(NO2)-
(AsPh3)2]+. Anal. Calcd for C54H45AgAs3NO2: C, 60.47; H, 4.23;
N, 1.31. Found: C, 60.32; H, 4.34; N, 1.38.
[AgNO2(SbPh3)] (15). Compound 15 was prepared similarly to
compound 1, by using AgNO2 (0.154 g, 1 mmol) and SbPh3 (0.353
g, 1 mmol), and recrystallized from ethanol. X-ray-quality crystals
were grown at 4 °C from MeCN. Yield: 60%. Mp: 147-148 °C.
IR (Nujol, cm-1) data: 3152vw, ν(C-H); 1430s, 1303w, 1180w,
[AgNO2{P(p-tolyl)3}3] (10). Compound 10 was prepared simi-
larly to 5, by using AgNO2 (0.154 g, 1 mmol) and P(p-tolyl)3 (0.913
g, 3 mmol), and recrystallized from ethanol. Yield: 46%. Mp:
180-183 °C. IR (Nujol, cm-1) data: 3173w, ν(C-H); 1392w,
1203m, 1189m, ν(NO2); 807s, δ(ONO); 516s, 509s, 490m, 429m,
1
ν(NO2); 847w, δ(ONO); 453s, 446sh, 268s, δ(Ph3Sb). H NMR
1
δ(PPh3). H NMR (CDCl3, 293 K): δ 2.31 (s, 27H, CH3), 7.06
(m, 18H, C6H4), 7.17 (m, 18H, C6H4). H NMR (CDCl3, 218 K):
(CDCl3, 293 K): δ 7.25-7.48 (mc, 15H, C6H5). Λmol (CH2Cl2,
concn ) 1.00 × 10-3 M): 0.4 Ω-1 cm2 mol-1. ESI MS (MeCN):
(+) 189 (5) [Ag(MeCN)2]+, 502 (70) [Ag(MeCN)(SbPh3)]+, 813
(100) [Ag(SbPh3)2]+, 968 (60) [Ag2(NO2)(SbPh3)2]+; (-) 178 (10)
[AgCl2]-, 199 (100) [Ag(NO2)2]-, 332 (40) [Ag2Cl2(NO2)]-, 353
(20) [Ag2(NO2)3]-. Anal. Calcd for C18H15AgNO2Sb: C, 42.65;
H, 2.98; N, 2.76. Found: C, 42.61; H, 3.14; N, 2.71.
[AgNO2(SbPh3)3] (16). Compound 16 was prepared similarly
to 1, by using AgNO2 (0.154 g, 1 mmol) and SbPh3 (1.059 g, 3
mmol). Compound 16 was recrystallized from ethanol. X-ray-
quality crystals were grown at 4 °C from ethanol. Yield: 60%.
Mp: 182-183 °C. IR (Nujol, cm-1) data: 3062w, 3046w, ν(C-
H); 1429s, 130br, 1200w, ν(NO2); 847w, δ(ONO); 453s, 446sh,
273s, 262s, δ(Ph3Sb). 1H NMR (CDCl3, 293 K): δ 7.22-7.40 (mc,
45H, C6H5). Λmol (CH2Cl2, concn ) 1.20 × 10-3 M): 0.4 Ω-1
cm2 mol-1. ESI MS (MeCN): (+) 502 (30) [Ag(MeCN)(SbPh3)]+,
813 (100) [Ag(SbPh3)2]+, 968 (30) [Ag2(NO2)(SbPh3)2]+. Anal.
Calcd for C54H45AgNO2Sb3: C, 53.47; H, 3.74; N, 1.15. Found:
C, 53.42; H, 3.83; N, 1.10.
Crystal Structure Determinations. Crystals for the X-ray work
were obtained in all cases (exception: 15 (MeCN, 4 °C)) from
ethanol, 13-16 at 4 °C. For compounds 5, 12, and 16, unique room
temperature data sets were measured using a single counter
instrument (T, ca. 295 K; 2θ/θ scan mode; monochromatic Mo KR
radiation; λ ) 0.71073 Å), yielding N reflections, No with I > 3σ(I)
being considered “observed” and used in the full matrix least
squares refinement after Gaussian absorption correction; for the
remainder, full spheres of low-temperature CCD area detector data
were measured (T, ca. 153 K; Bruker AXS instrument; ω-scans)
1
δ 2.29 (s, 27H, CH3), 6.83 (sbr, 36H, C6H4). 31P{1H} NMR (CDCl3,
293 K): δ 2.9 (s), 29.7 (s). 31P{1H} NMR (CDCl3, 218 K): 3.7
(dbr, 1J(31P-Ag) ) 193 Hz). Λmol (CH2Cl2, concn ) 1.00 × 10-3
M): 1.9 Ω-1 cm2 mol-1. ESI MS (MeCN): (+) 716 (100) [Ag-
(P(p-tolyl)3)2]+. Anal. Calcd for C63H63AgNO2P3: C, 70.92; H, 5.95;
N, 1.31. Found: C, 70.58; H, 6.21; N, 1.26.
[AgNO2{P(p-F-C6H4)3] (11). Compound 11 was prepared
similarly to 5, by using AgNO2 (0.154 g, 1 mmol) and P(p-F-
C6H4)3 (0.316 g, 1 mmol), and recrystallized from ethanol. Yield:
66%. Mp: 160 °C. IR (Nujol, cm-1) data: 3160w, ν(C-H); 1576s,
1461s, 1366br, 1219br, 1152br, ν(NO2); 823s, δ(ONO); 523s, 476s,
1
434s, 415s, 404s δ(PPh3). H NMR (CDCl3, 293 K): δ 7.1 (m,
9H, C6H4), 7.4 (m, 6H, C6H4). 31P{1H} NMR (CDCl3, 293 K): δ
12.8 (d, J(31P-Ag) ) 643 Hz). Λmol (CH2Cl2, concn ) 1.00 ×
1
10-3 M): 3.5 Ω-1 cm2 mol-1. ESI MS (MeCN): (+) 424 (15)
[Ag(P(p-F-C6H4)3)]+, 740 (100) [Ag(P(p-F-C6H4)3)2]+. Anal.
Calcd for C18H12AgF3NO2P: C, 45.99; H, 2.57; N, 2.98. Found:
C, 45.87; H, 2.64; N, 2.76.
[AgNO2(Pcy3)2] (12). Compound 12 was prepared similarly to
compound 5, by using AgNO2 (0.154 g, 1 mmol) and Pcy3 (0.561
g, 2 mmol). Compound 12 was recrystallized from ethanol. Yield:
56%. Mp: 205-210 °C. IR (Nujol, cm-1) data: 3159w ν(C-H);
1346m, 1225m, ν(NO2); 886s, 850s, δ(ONO); 512s, 487m, 465s,
400w, δ(Ph3P). 1H NMR (CDCl3, 293 K): δ 1.23 (mbr, 30H,
1
C6H11), 1.65 (sbr, 6H, C6H11), 1.78 (mbr, 30H, C6H11). H NMR
(CDCl3, 218 K): δ 1.18 (br, 30H, C6H11), 1.60 (br, 6H, C6H11),
1.73 (br, 30H, C6H11). 31P{1H} NMR (CDCl3, 293 K): δ 28.9 (d,
1J(31P-Ag) ) 435 Hz), 50.6 (s). 31P{1H} NMR (CDCl3, 218 K):
Nt(otal) reflections merging to N unique after “empirical”/multiscan
δ 28.4 (dd, J(31P-107Ag) ) 425 Hz, J(31P-109Ag) ) 491 Hz).
1
1
absorption correction (proprietary software), No with F > 4σ(F),
considered “observed”. Anisotropic displacement parameter forms
were refined for the non-hydrogen atoms, (x, y, z, Uiso)H constrained
at estimates (295 K data) or refined (153 K data) unless otherwise
noted. Conventional residuals R ()∑∆/∑|Fo|), Rw () [∑w∆2/
∑wFo2]1/2) on |F| at convergence are cited (weights: (σ2(F) +
0.0004F2)-1). Neutral atom complex scattering factors were em-
ployed, within the context of various versions of the Xtal program
Λ
mol (CH2Cl2, concn ) 1.40 × 10-3 M): 4.5 Ω-1 cm2 mol-1. ESI
MS (MeCN): (+) 430 (55) [Ag(Pcy3)]+, 668 (100) [Ag(Pcy3)2]+,
822 (100) [Ag2(NO2)(Pcy3)2]+. Anal. Calcd for C36H66AgNO2P2:
C, 60.50; H, 9.31; N, 1.96. Found: C, 60.22; H, 9.53; N, 2.05.
[AgNO2(AsPh3)2] (13). Compound 13 was prepared similarly
to compound 1, by using AgNO2 (0.154 g, 1 mmol) and AsPh3
(0.612 g, 2 mmol), and recrystallized from ethanol. Yield: 65%.
6636 Inorganic Chemistry, Vol. 41, No. 25, 2002

-
Variable Coordination Modes of NO2
system.29 Pertinent results are given below and in the tables and
figures (displacement ellipsoid amplitudes, 20% (295 K) and 50%
(153 K); hydrogen atom radii, 0.1 Å). Individual variations in
procedure (etc.) are cited as “variata”.
(g) Compound 13. [Ag(µ-ONO)(AsPh3)2]2 ≡ C72H60Ag2-
As4N2O4, M ) 1532.7. Triclinic, space group P1h, a ) 18.5301(7)
Å, b ) 14.0840(5) Å, c ) 14.1379(5) Å, R ) 61.087(1)°, â )
79.547(1)°, γ ) 77.195(1)°, V ) 3138 Å3. Dc(Z)1 dimer) ) 1.622
g cm-3. µMo ) 27.7 cm-1; specimen, 0.15 × 0.15 × 0.12 mm;
“T”min,max ) 0.69, 0.83. 2θmax ) 75°; Nt ) 65 568, N ) 32 417
(Rint ) 0.030), No ) 21 311; R ) 0.030, Rw ) 0.027; |∆Fmax| )
1.8(1) e Å-3. (x, y, z, Uiso)H constrained at estimates.
(a) Compound 1. [Ag(O2N)(PPh3)](∞|∞) ≡ C18H15AgNO2P,
M ) 416.2. Monoclinic, space group P21/c (C52h , No. 14), a )
10.191(1) Å, b ) 8.906(2) Å, c ) 18.086(2) Å, â ) 88.281(3)°,
V ) 1641 Å3. Dc(Z)4) ) 1.684 g cm-3. µMo ) 13.3 cm-1
;
specimen, 0.50 × 0.25 × 0.20 mm; “T”min,max ) 0.60, 0.83.
Variata. The complex is isomorphous with its Ph3Sb/AgCl, Br,
and I counterparts and is presented in that cell and coordinate
setting,32 the numbering of ligands 1 and 2 of molecule 2 being
interchanged.
2θmax ) 75°; Nt ) 33 205, N ) 8571 (Rint ) 0.026), No ) 7722;
R ) 0.029, Rw ) 0.042; |∆Fmax| ) 2.76(4) e Å-3
.
Variata. Compound 15 below is isomorphous and was refined
in the same cell and coordinate setting, with â conventionally
obtuse, requiring â acute in the present.
(h) Compound 14. [Ag(O2N)(AsPh3)3]‚2MeCN ≡ C58H51Ag-
As3N3O2, M ) 1154.7. Triclinic, space group P1h, a ) 13.391(3)
Å, b ) 13.839(3) Å, c ) 14.119(3) Å, R ) 84.994(4)°, â )
(b) Compound 2. [Ag(O2N)(PPh3)2] ≡ C36H30AgNO2P2, M )
678.5. Monoclinic, space group P21/c, a ) 11.908(2) Å, b )
18.364(2) Å, c ) 14.761(2) Å, â ) 101.121(2)°, V ) 3167 Å3.
Dc(Z)4) ) 1.423 g cm-3. µMo ) 7.7 cm-1; specimen, 0.4 × 0.3 ×
0.1 mm; “T”min,max ) 0.79, 0.89. 2θmax ) 58°; Nt ) 30 943, N )
7988 (Rint ) 0.025), No ) 6648; R ) 0.030, Rw ) 0.037;
89.131(4)°, γ ) 77.364(4)°, V ) 2453 Å3. Dc(Z)2) ) 1.508 g cm-3
.
µMo ) 23.8 cm-1; specimen, 0.27 × 0.03 × 0.03 mm; “T”min,max
)
0.74, 0.91. 2θmax ) 58°; Nt ) 24 593, N ) 12 458 (Rint ) 0.054),
No ) 6605; R ) 0.055, Rw ) 0.051; |∆Fmax| ) 1.2(1) e Å-3
(x, y, z, Uiso)H constrained at estimates.
.
|∆Fmax| ) 0.55(4) e Å-3
.
Variata. C and N of the solvent residues were refined with
isotropic displacement parameter forms. The cell and coordinate
setting follows that of the CuCl:SbPh3 (1:3) chloroform solvate33
(see below).
Variata. Cell and coordinate settings follow those of a previous
room temperature determination.30
(c) Compound 5. [Ag(O2N){P(o-tolyl3)}] ≡ C21H21AgNO2P,
M ) 458.3. Orthorhombic, space group Pbcn (D12h4 , No. 60), a )
13.467(6) Å, b ) 14.127(7) Å, c ) 20.298(5) Å, V ) 3862 Å3.
Dc(Z)8) ) 1.576 g cm-3. µMo ) 11.4 cm-1; specimen, 0.34 ×
0.58 × 0.67 mm; “T”min,max ) 0.60, 0.72. 2θmax ) 60°; Nt ) 11 973,
N ) 5628 (Rint ) 0.018), No ) 3556; R ) 0.036, Rw ) 0.044;
(i) Compound 15. [Ag(O2N)(SbPh3)](∞|∞) ≡ C18H15AgNO2Sb,
M ) 506.9. Monoclinic, space group P21/c, a ) 9.939(1) Å, b )
9.2233(9) Å, c ) 18.983(2) Å, â ) 90.064(2)°, V ) 1740 Å3.
Dc(Z)4) ) 1.935 g cm-3. µMo ) 26.9 cm-1; specimen, 0.35 ×
0.15 × 0.10 mm; “T”min,max ) 0.63, 0.83. 2θmax ) 75°; Nt ) 36 047,
N ) 9091 (Rint ) 0.037), No ) 7048; R ) 0.028, Rw ) 0.033;
|∆Fmax| ) 0.6(1) e Å-3
.
|∆Fmax| ) 1.9(1) e Å-3
.
Variata. A quadrant of data was measured.
(d) Compound 6. [Ag(O2N){P(o-tolyl3)}2] ≡ C42H42AgNO2P2,
M ) 762.6. Monoclinic, space group P21/n (C52h , No. 14 (vari-
ant)), a ) 12.516(2) Å, b ) 22.409(4) Å, c ) 13.020(2) Å, â )
92.183(4)°, V ) 3649 Å3. Dc(Z)4) ) 1.388 g cm-3. µMo ) 6.8
cm-1; specimen, 0.35 × 0.28 × 0.18 mm; “T”min,max ) 0.73, 0.86.
2θmax ) 75°; Nt ) 69 781, N ) 18 310 (Rint ) 0.036), No ) 12 855;
R ) 0.036, Rw ) 0.040; |∆Fmax| ) 1.30(7) e Å-3. (x, y, z, Uiso)H
constrained at estimates.
(j) Compound 16. [Ag(O2N)(SbPh3)3] ≡ C54H45AgNO2Sb3,
M ) 1213.1. Monoclinic, space group P21/c, a ) 19.1405(9) Å,
b ) 14.2688(7) Å, c ) 17.7907(9) Å, â ) 100.050(2)°, V ) 4784
Å3. Dc(Z)4) ) 1.684 g cm-3. µMo ) 21.2 cm-1; specimen, 0.35 ×
0.14 × 0.11 mm; “T”min,max ) 0.55, 0.88. 2θmax ) 75°; Nt ) 98 748,
N ) 25 089 (Rint ) 0.048), No ) 16 028; R ) 0.032, Rw ) 0.030;
|∆Fmax| ) 1.0(1) e Å-3
.
Variata. The cell and coordinate setting follow those of isomor-
phous unsolvated [AgI(PPh3)3]34 (see below); for a preliminary
determination carried out at ca. 295 K on a single counter
instrument, a ) 19.356(7) Å, b ) 14.236(3) Å, c ) 17.919(4) Å,
â ) 99.90(2)°, V ) 4895 Å3.
(e) Compound 11. [Ag(O2N){P(p-F-C6H4)3}] ≡ C36H24Ag2F6-
N2O4P2, M ) 470.1. Monoclinic, space group C2/c (C62h , No. 15),
a ) 13.333(2) Å, b ) 11.599(4) Å, c ) 22.787(3) Å, â ) 99.748-
(3)°, V ) 3473 Å3. Dc(Z)4 dimers) ) 1.798 g cm-3. µMo ) 13.0
cm-1; specimen, 0.20 × 0.20 × 0.11 mm; “T”min,max ) 0.72, 0.86.
2θmax ) 75°; Nt ) 29 249, N ) 8982 (Rint ) 0.027), No ) 6697;
Results and Discussion
R ) 0.030, Rw ) 0.044; |∆Fmax| ) 1.17(6) e Å-3
.
(f) Compound 12. [Ag(O2N)(Pcy3)2] ≡ C36H66AgNO2P2, M )
714.8. Triclinic, space group P1h (C1i , No. 2), a ) 9.105(4) Å, b )
9.821(2) Å, c ) 23.437(3) Å, R ) 94.53(1)°, â ) 96.67(2)°, γ )
116.11(2)°, V ) 1849 Å3. Dc(Z)2) ) 1.284 g cm-3. µMo ) 6.6
cm-1; specimen, 0.40 × 0.36 × 0.16 mm; “T”min,max ) 0.80, 0.90.
2θmax ) 50°; Nt ) 10 672, N ) 6484 (Rint ) 0.033), No ) 5416;
Syntheses. From the interaction of 1 equiv of AgNO2 and
1, 2, 3, or 4 equiv of tertiary monophosphine PPh3, P(o-
tolyl)3, P(m-tolyl)3, P(p-tolyl)3, P(p-F-C6H4)3, or Pcy3 in
ethanol at 60 °C, complexes 1-12 have been respectively
obtained in high yield (eq 1):
R ) 0.042, Rw ) 0.049; |∆Fmax| ) 0.89(3) e Å-3
.
AgNO2 + xPR3 f [AgNO2(R3P)x]
(1)
Variata. A second hemisphere of data was measured to 2θmax
)
40° and merged. The cell and coordinate setting follows that of
the parent nitrate counterpart,31 similar disorder being observed in
one of the substituent rings.
(31) Bowmaker, G. A.; Effendy; Harvey, P. J.; Healy, P. C.; Skelton, B.
W.; White, A. H. J. Chem. Soc., Dalton Trans. 1996, 2449-2457.
(32) Bowmaker, G. A.; Effendy; de Silva, E. N.; White, A. H. Aust. J.
Chem. 1997, 50, 641-651 (corrigendum: Bowmaker, G. A.; Effendy;
de Silva, E. N.; White, A. H. Aust. J. Chem. 1998, 51, 90).
(33) Rheingold, A. L.; Fountain, M. E. J. Cryst. Spectrosc. Res. 1984, 14,
549-557.
(29) Hall, S. R., du Boulay, D. J., Olthof-Hazekamp, R., Eds. The Xtal 3.7
System (Current Version); University of Western Australia: Crawley,
Western Australia, 2001.
(30) Hanna, J. V.; Ng, S.-W., Acta Crystallogr., Sect. C 1999, 55, IUC
9900029 (.cif access).
(34) Engelhardt, L. M.; Healy, P. C.; Patrick, V. A.; White, A. H. Aust. J.
Chem. 1987, 40, 1873-1880.
Inorganic Chemistry, Vol. 41, No. 25, 2002 6637

Cingolani et al.
Table 1. 31P{1H} NMR Data for R3P Containing Complexes
1: R ) Ph, x ) 1 5: R ) o-tolyl, x ) 1 9: R ) m-tolyl, x ) 3
2: R ) Ph, x ) 2 6: R ) o-tolyl, x ) 2 10: R ) p-tolyl, x) 3
δ(31P),
293 K, 1J(31P-Ag), δ(31P),
1J(31P-xAg),
11: R ) p-F-C6H4, x ) 1
3: R ) Ph, x ) 3 7: R ) m-tolyl, x ) 1
4: R ) Ph, x ) 4 8: R ) m-tolyl, x ) 2 12: R ) cy, x ) 2
[
]
compd
ppm
Hz
ppm
Hz
1
2
3
16.5 d br
9.3 s
5.2 s
621
16.1 dda 666 (x ) 107); 769 (x ) 109)
8.95 dda 413 (x ) 107); 476 (x ) 109)
The 1:2 and 1:3 adducts 6 and 9, respectively, have been
5.6 da 228
32.2 s
obtained also when this reaction was conducted in excess
of the P-donor (>4 equiv), whereas when equimolar quanti-
ties of AgNO2 and P(p-tolyl)3 or Pcy3 were employed, no
1:1 adduct was obtained, deposition of metallic silver rapidly
occurring, even if the reaction was carried out in the dark.
The same behavior, which does not seem to correlate with
any property of the P-donor, has been previously described
in the literature.22 The reaction between P(p-F-C6H4)3 and
AgNO2 afforded the 1:1 adduct 11 also in excess of
phosphine.
4
4.7 br
5.6 da 228
32.2 s
5
6
7
8
-17.7 d br
-19.0 br
10.5 br
9.5 s br,
29.9 s
-19.2b
695
-11.0 brb
10.0 da 660
8.8 dda 411 (x ) 107); 475 (x ) 109)
32.2 s
9
4.9 s
29.9 s
5.1 da 239
10.4 s br
32.3 s
10
2.9 s
29.7 s
12.8 d
28.9 d
50.6 s
3.7 d bra 193
11
12
643
435
From the interaction of AgNO2 with 2 mol of AsPh3 or 1
mol of SbPh3, in ethanol at 60 °C, complexes 13 and 15
have been obtained respectively in high yield (eq 2):
28.4a
425 (x ) 107); 491 (x ) 109)
a T ) 218 K. b T ) 223 K.
AgNO2 + xLPh3 f [AgNO2(LPh3)x]
(2)
1
In the H NMR spectra of 1-16 in CDCl3 (see Experi-
mental Section), the signals due to the triorganophosphines,
-arsines, and -stibines are in the range of 6.80-7.80 ppm,
showing a different pattern of signals with respect to those
found for the free donors, confirming the existence, at least
partial, of the complexes in solution. The room temperature
1H NMR spectra of derivatives 5-9 exhibit only one set of
signals for the methyl protons of the P-donor. On cooling
the CDCl3 solutions of 5-9 to 223 K, some weak additional
signals appeared, typical of the free donor, suggesting partial
dissociation of the complexes.
13: L ) As, x ) 2 15: L ) Sb, x ) 1
14: L ) As, x ) 3 16: L ) Sb, x ) 3
[
]
From the interaction of 1 equiv of AgNO2 with 3 equiv
of AsPh3 or SbPh3, in ethanol at room temperature, com-
plexes 14 and 16 have been obtained respectively in high
yield (eq 2). These compounds were obtained also when
excesses of the phosphorus donors were employed (>3
equiv).
All derivatives 1-16 show good solubility in chlorinated
solvents, acetonitrile, acetone, and dimethyl sulfoxide (DMSO),
but they are insoluble in diethyl ether, alcohols, aromatics,
and aliphatic hydrocarbons. They are nonelectrolytes in CH2-
Cl2 solution, the Λmol values being always lower than 4.5
Ω-1 cm2 mol-1. In the case of the 1:4 adduct 4 this could be
due to formation in solution of a solvated ion pair or,
alternatively, to dissociation of PPh3 ligands from the silver
with consequent reassociation of the counterion (see below).
Spectroscopy. The infrared spectra of derivatives 1-16
(see Experimental Section) are consistent with the formula-
tions proposed, showing all of the bands required by the
presence of the nitrito group and of the phosphorus donor,35,36
the phosphine ligand absorptions being only slightly shifted
with respect to those of the free donors. In the far-IR spectra
of all derivatives 1-12 we assigned, on the basis of a
previous report on phosphino copper(I) derivatives,22 the
broad absorptions near 500 cm-1 and those at 400-450 cm-1
to Whiffen’s y and t vibrations, respectively, whereas some
bands in the region 300-400 cm-1, similar to those described
in the literature for some silver(I) nitrato derivatives,22b can
be tentatively assigned to ν(Ag-O) vibrations.
31P chemical shifts (CDCl3 solution) and 31P-Ag coupling
constants for derivatives 1-12, are reported in Table 1. They
have been found to be dependent on the dilution of the
solutions. Our experiments have been carried out at a
concentration of 0.02 mol/L.
The 31P NMR spectrum at room temperature of complex
6 consists of a broad singlet, presumably due to rapid
exchange equilibria, also unresolved in the spectrum recorded
at 218 K. Whereas for derivatives 2-4 and 7-10, for which
at room temperature only a broad singlet was found,
exchange is quenched at lower temperature, and one and/or
two unresolved doublets or resolved pairs of doublets, arising
from coupling between the phosphorus and silver atom, are
observed in the accessible temperature range. In particular
in the spectra of derivatives 1, 2, 8, and 12 typical pairs of
doublets, due to 1J(31P-107Ag) and 1J(31P-109Ag) coupling,
1
are resolved at 218 K and the observed J(107Ag)/1J(109Ag)
ratio is in good agreement with that calculated from the
gyromagnetic ratio of the Ag nuclei γ(107Ag)/γ(109Ag) (Figure
2).37 For derivatives 1, 5, 11, and 12 such doublets were
also observed at room temperature, suggesting that rapid
exchange equilibria are not operative in the cases of 1:1
adducts or sterically hindered phosphines. The signal due to
(35) (a) Shobatake, K.; Postmus, C.; Ferraro, J. F.; Nakamoto, K. Appl.
Spectrosc. 1969, 23, 12-16. (b) Bradbury, J.; Forest, K. P.; Nuttall,
R. H.; Sharp, D. W. A. Spectrochim. Acta 1967, 23, 2701-2704.
(36) (a) Deacon, G. B.; Jones, R. A. Aust. J. Chem. 1963, 16, 499-503.
(b) Perreault, D.; Drouin, M.; Michel, A.; Misckowski, V. M.;
Schaefer, W. P.; Harvey, P. D. Inorg. Chem. 1992, 31, 695-702.
(37) Goodfellow, R. J.: Post-Transition Metals, Copper to Mercury. In
Multinuclear NMR; Mason, J., Ed.; Plenum Press: New York, 1987;
Chapter 21, pp 563-589.
6638 Inorganic Chemistry, Vol. 41, No. 25, 2002

-
Variable Coordination Modes of NO2
Figure 3. (a) Unit cell contents of AgNO2:SbPh3 (1:1)(∞|∞) (15), down b
(the polymer axis) (cf. refs 19 and 20 (see text)). (b) Single strand of the
polymer. (The PPh3 adduct (1) is isomorphous).
Figure 2. 31P NMR spectra of derivative 2 at room temperature (a) and
218 K (b).
Section) indicate that these derivatives undergo loss of the
anionic NO2 ligand. The isotopic distribution of these
species is in accord with the calculated composition.
The aggregation behavior is strongly dependent on the
stoichiometry of the adducts and the solvent employed: for
each free phosphine is upfield with respect to the corre-
sponding silver(I) complex. The magnitudes of ∆ (∆ )
δ31Pcomplex - δ31Pfree ligand) and the coupling constants
decrease with the decreasing basicity, also correlating with
steric bulk of the ligands.
The chemical shifts and J(Ag-31P) coupling constants
are strongly dependent on the stoichiometric ratio Ag/P
(P ) triorganophosphine). The higher J(Ag-31P) values
found for derivatives 1, 5, 7, and 11, typical of monophos-
phine adducts, may be rationalized in terms of formation of
a monuclear [Ag(NO2)PR3] fragment, containing an sp
hybridized silver, arising from the dissociation of the poly-
and dinuclear species, respectively.38 The derivatives 2, 8,
and 12 exhibit 1J(Ag-31P) values, consistent with the
presence of two phosphines on a two- or three-coordinate
silver atom. The derivatives 3, 4, and 9 present identical low-
temperature 31P spectra with 1J(Ag-31P) values in the range
of 228-240 Hz, typical of compounds with an AgP3 or AgP4
central core.39
-
1
(38) (a) Muetterties, E. L.; Alegranti, C. W. J. Am. Chem. Soc. 1970, 92,
4114-4115. (b) Muetterties, E. L.; Alegranti, C. W. J. Am. Chem.
Soc. 1972, 94, 6386-6391. (c) van der Ploeg, A. F. M. J.; van Koten,
G.; Spek, A. L. Inorg. Chem. 1979, 18, 1052-1060. (d) van der Ploeg,
A. F. M. J.; van Koten, G. Inorg. Chim. Acta 1981, 51, 225-239. (e)
Barrow, M.; Bu¨rgi, H.-B.; Camalli, M.; Caruso, F.; Fischer, E.;
Venanzi, L. M.; Zambonelli, L. Inorg. Chem. 1983, 22, 2356-2362.
(f) Socol, S. M.; Verdake, R. A. Inorg. Chem. 1984, 23, 3487-3493.
(g) Socol, S. M.; Jacobson, R. A. Verkade, J. G. Inorg. Chem. 1984,
23, 88-94. (h) Barron, P. F.; Dyason, J. C. Healy, P. C.; Engelhardt,
L. M.; Skelton, B. W.; White, A. H. J. Chem. Soc., Dalton Trans.
1986, 1965-1970. (i) Camalli, M.; Caruso, F. Inorg. Chim. Acta 1987,
127, 209-213. (j) Dean, P. A: W. Vittal, J. J.; Srivastava, R. S. Can.
J. Chem. 1987, 65, 2628-2633. (k) Camalli, M.; Caruso, F. Inorg.
Chim. Acta 1988, 144, 205-211. (l) Obendorf, D.; Probst, M.;
Peringer, P.; Falk, A.; Muller, N. J. Chem. Soc., Dalton Trans. 1988,
1709-1711. (m) Bowmaker, G. A.; Effendy; Harvey, P. J.; Healy, P.
C.; Skelton, B. W.; White, A. H. J. Chem. Soc., Dalton Trans. 1996,
2459-2466.
1
(39) (a) Di Bernardo, P.; Dolcetti, G.; Portauova, R.; Tolazzi, M.; Tomat,
G.; Zanonato P. Inorg. Chem. 1990, 29, 2859-2862. (b) Harker, C.
S. W., Tiekink, E. R. T. J. Coord. Chem. 1990, 21, 287-293.
The positive electrospray mass spectra of complexes 1-16
(the most relevant data are reported in the Experimental
Inorganic Chemistry, Vol. 41, No. 25, 2002 6639

Cingolani et al.
Table 2. Selected Geometries: AgNO2:EPh3 (1:1) (E ) P, Sb (1, 11, 15))
(a) AgNO2:EPh3 (1:1)(∞|∞) (E ) P, Sb) (1, 15)a
Distances (Å)
Ag-E
Ag-N′
N-O(1)
2.3918(4), 2.6423(3)
2.563(1), 2.365(2)
1.231(2), 1.209(3)
Ag-O(1)
Ag-O(2)
N-O(2)
2.610(1), 2.498(2)
2.298(1), 2.392(2)
1.267(2), 1.245(3)
Angles (deg)
E-Ag-O(1)
E-Ag-O(2)
E-Ag-N′
O(1)-N-O(2)
Ag-O(1)-N
Ag-O(2)-N
119.06(3), 108.75(5)
152.75(3), 139.64(5)
106.90(3), 103.60(5)
115.4(1), 117.4(2)
89.88(9), 93.8(1)
O(1)-Ag-O(2)
N′-Ag-O(1)
N′-Ag-O(2)
O(1)-N-Ag′′
O(2)-N-Ag′′
114.71(4), 123.54(7)
99.87(4), 116.67(7)
50.45(4), 50.74(6)
116.1(1), 120.3(2)
128.34(9), 121.5(2)
104.26(9), 98.0(1)
(b) AgNO2:(p-F-C6H4)3P (1:1)2 (11)b
Distances (Å)
Ag-O(1′)
N-O(1)
Ag-P
2.3571(4)
2.399(1)
2.342(1)
3.9821(6)
2.636(2)
1.258(2)
1.251(3)
Ag-O(1)
Ag-O(2)
Ag‚‚‚Ag′
N-O(2)
Angles (deg)
P-Ag-O(1)
P-Ag-O(2)
P-Ag-O(1′)
O(1)-N-O(2)
Ag-O(1)-Ag′
147.07(4)
O(1)-Pg-O(2)
52.73(6)
75.56(5)
95.92(6)
95.1(1)
98.0(1)
107.0(1)
148.21(5)
111.58(3)
114.2(2)
O(1)-Ag-O(1′)
O(2)-Ag-O(1′)
Ag-O(1)-N
104.44(6)
Ag-O(2)-N
Ag-O(1′)-N
a Primed and doubly primed atoms are glide related (by 1 - x, y - 1/2, 1/2 + z); 1 - x, 1/2 + y, 1/2 + z). Ag, Ag′′ lie out of the NO2 plane by 0.103(6),
-0.169(7) Å (E ) P), 0.10(1), -0.36(1) Å (E ) Sb). τ(Ag-P-C(n1)-C(ortho), n ) 1-3) are 41.2(1), 57.0(1), 51.8(1)° (1); 44.0(2), 60.5(2), 44.8(2)° (15).
b Primed atoms are inversion related. The Ag2O(1)2/NO2 interplanar dihedral angle is 109.0(1)°. τ(Ag-P-C(n1)-C(n6), n ) 1-3) are 52.8(1), 27.2(1),
32.2(2)°.
most of the systems investigated aggregation of phosphine,
stibine, and arsine donors with Ag cations is significantly
present in acetonitrile, also at concentrations of 10-3 M.
Aggregates containing a single silver(I) ion dominate sig-
nificantly over adducts containing two silver atoms.
Under our conditions in acetonitrile also a species is noted
at m/z 147.9, which corresponds to a 1:1 adduct of Ag(I)
with the solvent. Although far less abundant, the higher
adduct [Ag(MeCN)2]+ is also observed at m/z 188.9. The
predominant peaks corresponding to ions containing silver-
(I) are those that originate from the successive addition of
ER3 ligands and formation of [Ag(ER3)n]+ ions (n ) 1 or
2). Other relevant peaks present in the spectra of 1-7 and
12-16 are attributed to the formation of the bimetallic
species [Ag2(NO2)(ER3)2]+. These ions undoubtedly contain
bridging nitrito groups. A careful inspection of the data
reveals that the species [Ag(ER3)2]+ is always the more
abundant species in the gas phase.
Acetonitrile itself behaves as ligand toward silver(I) ions,
and this is manifest in evidence for the formation of the ions
[Ag(MeCN)]+, [Ag(MeCN)2]+, and [Ag(MeCN)(ER3)]+.
However, for the various species with coordination numbers
of two or three, evidence for species containing coordinated
acetonitrile ligands was insignificant, suggesting that MeCN
cannot compete in coordinating ability with ER3 donors.
The negative electrospray mass spectra are always domi-
nated by the presence of molecular peaks due to [AgCl2]-,
[Ag(NO2)2]-, [Ag2Cl2(NO2)]-, and [Ag2(NO2)3]-. The ab-
sence of [Ag2(NO2)]+ and the abundance of [Ag(NO2)2]-
species can be understood as a consequence of the ion
distribution between both positive and negative ion en-
sembles.
It is likely that quantitative ESI-MS does not represent
the relative distribution of species in solution, charged species
present in the gas phase being only detected; however,
systematic studies of solution aggregation by ESI-MS should
yield important information regarding nucleation prior to
crystallization such that the process of self-assembly may
be better understood.
X-ray Discussion. The present array of structural studies
requires consideration alongside a series of analogues previ-
ously structurally defined, most notably (a) other AgNO2:
ER3 adducts and (b) other AgX:R3E adducts of similar form.
Complexes pertinent to (a) are few in number; more
generally, an appreciable proportion of nitrite complexes
presents difficulties with respect to the description of the
anion, which is often ill-defined, exhibiting displacement
envelopes of unreasonably large amplitude, even at low
temperature, indicative of high “thermal” motion and/or
disordered components contained within the envelopes,
possibly indicative of some presence of alternative diverse
coordination modes. Whatever the explanation, derivative
associated geometrical parameters should in such circum-
stances be considered circumspectly. Unsurprisingly, in a
number of cases, their crystals are isomorphous with various
nitrate counterparts and, not infrequently, beyond (see
below). Pertinent to the present work, we note the structure
determination of AgNO2:PPh3 (1:2) (unsolvated)30 and its
dichloromethane solvate,40 the latter isomorphous with CuX-
(Ph3P)2‚1/2S (X ) Cl, Br/S ) C6H6; X ) BH4/S ) py).32
Among the AgX:R3E analogues extensive surveys are
recently available for Ph3E adducts of 1:1,23,41 1:2,32 1:3,42
(40) Belaj, F.; Trnoska, A.; Nachbaur, E., Acta Crystallogr., Sect C 1998,
54, 727-728.
6640 Inorganic Chemistry, Vol. 41, No. 25, 2002

-
Variable Coordination Modes of NO2
Figure 5. (a) Single molecule of AgNO2:P{o-tolyl3} (1:1) (5). (b) Unit
cell contents, projected down a.
Figure 4. (a) Dimer of AgNO2:P(p-C6H4F)3 (1:1)2 (11) projected normal
to the central Ag2O2 plane. (b) Unit cell contents projected down b.
the others completing chelates to either side (E ) P, As) or,
with a pair of oxygens chelating one silver atom, the
remaining oxygen bridging to a successive one. The latter
form, with the nitrogen lone pair replacing the third oxygen,
is found in the arrays herein described for the 1:1 silver(I)
nitrite adducts with EPh3 (E ) P (1) and Sb (15) (we have
been unable to obtain satisfactorily crystalline the E ) As
analogue), the two adducts being isomorphous in a cell
(Figure 3), which is very similar in proportions to that found
for AgNO3:P, AsPh3 (1:1)(∞|∞) (monoclinic, P21/c, a ∼ 10.7
Å, b ∼ 18.6 Å, c ∼ 9.1 Å, â ∼ 100°, Z ) 4),19,20 except that
b and c are interchanged (a not infrequent occurrence in P21/c
pairs of polymorphs); the propagator of the polymer in the
latter is a 2-fold screw (as in the present pair), cf. a glide
plane in the stibine adduct. In all cases, one formula unit,
devoid of crystallographic symmetry comprises the asym-
metric unit of the structure. While it might reasonably be
surmised that the missing arsine analogue of the present
should also be isomorphous, history has shown the need to
1:443 stoichiometry. Among the 1:1 complexes, relative to
the remainder, the X ) halide adducts are more clearly
demarcated from the structural types associated with the
oxyanions, the former adopting tetrameric “cubane” or “step”
structures23 and the latter oxygen-bridged one-dimensional
polymers for, in particular, the nitrates.41 Adducts AgNO3:
EPh3 (1:1)(∞|∞) have been defined for all E ) P,19 As,44 and
Sb,41 the E ) P and As adducts being isomorphous and the
E ) Sb not so; although the polymer is of similar form, the
role of the nitrate is to bridge successive silver atoms by
coordination through one oxygen, commonly bridging, and
(41) Effendy; Kildea, J. D.; White, A. H. Aust. J. Chem. 1997, 50, 671-
674.
(42) Effendy; Kildea, J. D.; White, A. H. Aust. J. Chem. 1997, 50, 587-
604 (corrigendum: Effendy; Kildea, J. D.; White, A. H. Aust. J. Chem.
1998, 51, 90).
(43) Bowmaker, G. A.; Effendy; Hart, R. D.; Kildea, J. D.; de Silva, E.
N.; Skelton, B. W.; White, A. H. Aust. J. Chem. 1997, 50, 539-552.
(44) Baker, L.-J.; Bowmaker, G. A.; Camp, D.; Effendy; Healy, P. C.;
Schmidbaur, H.; Stiegelmann, O.; White, A. H. Inorg. Chem. 1992,
31, 3656-3662.
Inorganic Chemistry, Vol. 41, No. 25, 2002 6641

Cingolani et al.
Figure 6. (a) Single molecule of AgNO2:P{o-tolyl3} (1:2) (6). (b) Single molecule of AgNO2:Pcy3 (12) (1:2) (unit cell contents are depicted in ref 44).
(c) Unit cell contents of AgNO2:PR3 (1:2), PR3 ) (i) P{o-tolyl3} (6) and (ii) PPh3, (2), projected down a in both cases.
treat such comparative/extrapolative prognostications cir-
cumspectly. The geometries of the two present adducts are
compared in Table 2, the increased Ag-E distance in the
stibine adduct offset by shortened Ag-N′, with concomitant
effects on the N-O distances; the mean Ag-O distance
remains remarkably constant (2.45 Å, E ) P, Sb (both)),
although the two distances are much more nearly equivalent
in the stibine adduct. In the nitrates, Ag-P, Sb are 2.369-
(6), 2.6453(9) Å. By the above standards, the 1:1 adduct of
AgNO2 with (p-F-C6H4)3P, 11, is unusual, being binuclear;
the nitrite chelates the (R3E)Ag array somewhat unsym-
metrically (Table 2; Figure 4a), the oxygen associated with
the longer of the two Ag-O bonds, O(1), interacting with
the silver atom of an inversion related moiety to form a
dimer, with the planar components of the structure pertinent
to crystal packing (Figure 4b).
o-Tolyl3P is a sterically more hindered base than PPh3,
and we find that in its 1:1 adduct with AgNO2, 5, a
mononuclear form, one [Ag(O2N)P(o-tolyl3)] molecule,
Figure 5a, devoid of crystallographic symmetry, comprises
the asymmetric unit of the structure, the aromatic substituents
disposed umbrella-like about the Ag-P bond and the nitrite
O,O′-bidentate a rare example of a quasi-linear P-Ag-X
array, the only other examples described also being with the
bulky phosphine P(2,4,6-(MeO)3C6H2)3 and with X ) Cl,
Br44 genuinely unidentate, wherein Ag-P are 2.342(1),
2.379(1) Å, respectively. In the present, Ag-P is 2.3616(9)
and Ag-O(1,2) are 2.268(3), 2.401(4) Å, P-Ag-O(1,2) are
160.42(9), 146.34(9), with O(1)-Ag-O(2) 52.5(1) and Ag-
O(1,2)-N 100.1(3), 93.3(3)°; N-O(1,2) are 1.231(6), 1.236-
(6) Å. Ag lies 0.04(2) Å out of the NO2 plane. However,
the molecules pack in a manner not dissimilar to those
6642 Inorganic Chemistry, Vol. 41, No. 25, 2002

-
Variable Coordination Modes of NO2
Table 3. Selected Geometries: Mononuclear AgNO2:PR3 (1:2) (2, 6, 12)a
Distances (Å)
Ag-P(1)
Ag-P(2)
Ag-O(1)
Ag-O(2)
N-O(1)
N-O(2)
2.412(1); 2.4421(7), 2.4325(6); 2.459(1); 2.4416(5)
2.440(1); 2.4372(7), 2.4303(6); 2.461(1); 2.4437(5)
2.481(3); 2.440(2), 2.433(2); 2.448(6); 2.471(2)
2.386(3); 2.433(2), 2.434(1); 2.532(4); 2.495(2)
1.253(4); 1.244(5), 1.257(2); 1.223(6); 1.247(3)
1.259(4); 1.236(5), 1.234(2); 1.215(9); 1.241(2)
Angles (deg)
P(1)-Ag-P(2)
P(1)-Ag-O(1)
P(1)-Ag-O(2)
P(2)-Ag-O(1)
P(2)-Ag-O(2)
O(1)-Ag-O(2)
O(1)-N-O(2)
128.67(4); 129.26(3), 129.57(2); 132.03(5); 148.04(2)
120.81(8); 110.67(6), 110.81(4); 110.5(1); 117.77(4)
118.35(8); 110.96(6), 111.83(4); 108.5(1); 92.96(4)
102.06(5); 114.27(6), 113.91(4); 115.5(1); 91.86(5)
109.99(6); 115.23(6), 113.77(4); 112.0(4); 116.73(4)
51.3(1); 50.6(1), 51.30(5); 47.9(1); 49.59(6)
114.1(3); 114.1(3), 115.1(2); 112.1(6); 113.6(2)
Torsion Angles (deg) (Carbon Atoms Denoted by Number Only)
Ag-P(1)-C(111)-C(112)
Ag-P(1)-C(121)-C(122)
Ag-P(1)-C(131)-C(132)
Ag-P(2)-C(211)-C(212)
Ag-P(2)-C(221)-C(222)
Ag-P(2)-C(231)-C(232)
-64.5(4); 50.78(3), 50.6(2); -62.4(4);b -170.5(1)
-29.3(3); 34.4(3), 34.5(2); -56.9(3);b 54.3(1)
-35.8(4); 28.0(3), 26.6(2); -33.0(4);b 53.8(1)
-30.3(4); 49.8(3), 49.0(2); -161.2(4);b 56.5(1)
-22.8(3); 20.0(3), 20.3(2); -62.4(4);b 51.4(2)
-47.5(3); 31.4(3), 30.4(2); -52.6(3);b -172.0(1)
Out of NO2-Plane Distances (Å)
0.06(2), 0.02(2); 0.005(8); 0.01(3); 0.067(9)
δAg
a The values in each entry are for R ) Ph (CH2Cl2 solvate40); unsolvated room temperature,30 low temperature (the present, 2); Cy, 12; o-tolyl, 6.
b Ag-P(n)-C(nm1)-C(nm6) are 60.7(3), 174.0(3), -160.9(4), 33.8(11), 60.1(3), 176.9(3)°.
Table 4. Selected Geometries: AgNO2:AsPh3 (1:2) (13)a
Distances (Å)
Ag(n)-As(n1)
Ag(n)-As(n2)
N(n)-O(n1)
N(n)-O(n2)
2.5236(2), 2.5432(2)
2.5352(2), 2.5520(2)
1.258(2), 1.262(2)
1.233(3), 1.240(3)
Ag-O(n1)
2.374(2), 2.368(2)
2.611(2), 2.735(2)
2.619(1), 2.566(1)
4.1482(3)
Ag-O(n2)
Ag-O(n1)
Ag(n)‚‚‚Ag(n)
O(n1) ‚‚‚O(n1)
2.789(2), 2.775(2)
Angles (deg)
As(n1)-Ag(n1)-As(n2)
As(n1)-Ag(n)-O(n1)
As(n1)-Ag(n)-O(n2)
As(n1)-Ag(n)-O(n1)
O(n2)-Ag(n)-O(n1)
Ag(n)-O(n1)-Ag(n)
O(n1)-N(n)-O(12)
N(n)-O(n1)-Ag(n)
127.17(1), 130.26(1)
110.03(3), 110.61(3)
99.47(3), 98.87(3)
119.23(3), 119.71(3)
114.37(5), 114.06(5)
112.29(5), 111.69(5)
113.9(2), 114.0(2)
139.4(2), 136.7(1)
As(n2)-Ag(n)-O(n1)
As(n2)-Ag(n)-O(n2)
As(n2)-Ag(n)-O(n1)
O(n1)-Ag(n)-O(n2)
O(n1)-Ag(n)-O(n1)
Ag(n)-O(n1)-N(n)
Ag(n)-O(n2)-N(n)
121.17(3), 115.49(3)
103.80(3), 98.26(3)
92.78(4), 94.41(4)
49.24(6), 47.91(5)
67.71(5), 68.31(5)
104.0(1), 107.9(2)
92.9(1), 90.2(1)
Torsion Angles (deg) (Carbon Atoms Denoted by Number Only)
Ag(n)-As(n1)-n111-n112
Ag(n)-As(n1)-n121-n122
Ag(n)-As(n1)-n131-n132
40.7(1), 51.3(1)
27.7(2), 36.0(2)
58.7(2), -6.1(2)
Ag(n)-As(n2)-n211-n212
Ag(n)-As(n2)-n221-n222
Ag(n)-As(n2)-n231-n232
45.0(1), 21.6(2)
29.9(2), 30.8(2)
45.3(2), 92.6(2)
a The two values in each entry are for dimers n ) 1,2, each being centrosymmetric; centrosymmetrically related atoms are italicized. The nitrite NO2
planes make dihedral angles of 31.2(2), 39.9(2)° with the central AgO2Ag plane; silver atom deviations Ag(n), Ag(n) from their respective nitrite planes are
0.11(1), -1.076(6); 0.02(1), -1.048(5) Å.
generating the polymer with EPh3 (Figure 5b), although the
closest Ag‚‚‚anion distance Ag‚‚‚N (1 - x, y, 1/2 - z) is
3.955(4) Å.
the form [Ag(O2NO)(Pcy3)2], wherein the chelate is unsym-
metrical (Ag-O, 2.47(1), 2.79(1) Å; Ag-P, 2.440(2), 2.451-
(2) Å; P-Ag-P, 139.14(9)°); the present E ) P, nitrite
analogue is similar, Ag-O more symmetrical, with P-Ag-P
considerably diminished. The same form is also found in
[Ag(O2N)(PPh3)2], 2, previously recorded in a room tem-
perature study30 and redetermined at low temperature here
for the sake of comparability with the Pcy3 and P(o-tolyl)3
counterparts (Table 3). Perhaps the most remarkable variation
across the array is found in the P-Ag-P angle, where the
disparity between the value for the P(o-tolyl)3 array vis-a`-
vis the remainder is considerable. It is unlikely to be a
consequence of “lattice forces”, but whether the implication
is that P(o-tolyl)3 is a markedly “bulkier” ligand than Pcy3
or whether the difference is electronic is debatable. Interest-
The same ligand also forms an adduct of 1:2 stoichiometry,
also mononuclear, [Ag(O2N){P(o-tolyl)3}2], 6, the nitrite still
an O,O′-chelate, and the molecule having quasi-2-symmetry
(Figure 6a). A mononuclear 1:2 complex, 12, is also formed
with the other common sterically bulky PR3 entity, namely,
Pcy3 (Figure 6b). A considerable array of mononuclear AgX:
Ecy3 (1:2) complexes have been defined for both E ) P31
and As,45 wherein two common crystalline forms are found,
one monoclinic C2/c and the other a derivative P1h. Both
AgNO3:Ecy3 (1:2) (E ) P, As) are triclinic, the molecule of
(45) Bowmaker, G. A.; Effendy; Skelton, B. W.; White, A. H. J. Chem.
Soc., Dalton Trans. 1998, 2123-2129.
Inorganic Chemistry, Vol. 41, No. 25, 2002 6643

Cingolani et al.
Table 5. Selected Geometries:AgNO2:EPh3 (1:2) (14, 16)a
Distances (Å)
Ag-E(1)
Ag-E(2)
Ag-E(3)
Ag-O(1)
Ag-O(2)
N-O(1)
N-O(2)
2.593(1); 2.7816(2), 2.7434(5)
2.6347(9); 2.7464(2), 2.7185(6)
2.635(1); 2.7168(2), 2.6890(8)
2.516(6); 2.679(3), 2.861(9)
2.529(8); 2.371(2), 2.375(7)
1.21(1); 1.240(3), 1.115(9)
1.24(1); 1.231(3), 1.121(8)
Angles (deg)
E(1)-Ag-E(2)
E(1)-Ag-E(3)
E(1)-Ag-O(1)
E(1)-Ag-O(2)
E(2)-Ag-E(3)
E(2)-Ag-O(1)
E(2)-Ag-O(2)
E(3)-Ag-O(1)
E(3)-Ag-O(2)
O(1)-Ag-O(2)
O(1)-N-O(2)
Ag-O(1)-N
112.76(3); 110.286(7), 114.23(2)
112.55(3); 107.210(7), 110.69(2)
107.6(1); 86.78(6), 85.6(2)
113.2(1); 111.85(6), 109.1(2)
113.28(3); 111.221(7), 113.93(2)
122.3(2); 140.11(5), 131.6(2)
78.7(2); 92.88(5), 92.3(2)
85.6(2); 96.47(6), 96.9(2)
121.9(2); 122.49(6), 115.5(2)
47.5(2); 47.36(7), 39.6(2)
111.9(8); 111.9(2), 110.0(7)
101.0(5); 92.1(2), 90.8(6)
99.3(6); 108.2(2), 119.5(5)
Ag-O(2)-N
Torsion Angles (deg)
(Carbon Atoms Denoted by Number Only)
Ag-E(1)-111-112
13.7(6); 34.7(2), 23.3(5)
54.9(6); 19.4(3), 39.0(7)
41.2(6); 48.9(2), 41.4(5)
20.4(6); 26.4(2), 34.4(5)
50.4(6); 40.9(2), 38.1(5)
24.4(6); 24.3(2), 24.0(6)
46.1(6); -0.7(2), 3.8(5)
4.5(6); 48.3(2), 54.6(5)
51.5(6); 65.2(2), 59.2(5)
Ag-E(1)-121-122
Ag-E(1)-131-132
Ag-E(2)-211-212
Ag-E(2)-221-222
Ag-E(2)-231-232
Ag-E(3)-311-312
Ag-E(3)-321-322
Ag-E(3)-331-332
a Values in each entry correspond to (a) E ) As (bis(acetonitrile) solvate);
E ) Sb [cf. the present room-temperature study; Ag-Sb(1,2,3)-O(1,2),
2.8137(7), 2.7461(8), 2.726(1), 2.53(1), 2.391(7) Å; Sb(1)-Ag-Sb(2,3),
108.89(2), 106.59(2)°; Sb(2)-Ag-Sb(3), 111.62(2)°], followed by those
of its isomorphous nitrate counterpart (ref 52, a room temperature study).
Figure 7. Dimers of AgNO2:AsPh3 (1:2) (13).
ingly, this increase in angle is not accompanied by any
noticeable shortening in Ag-P, which are remarkably
constant regardless of R, as also are parameters involving
the nitrite groups which are twisted about the quasi-2-axis
passing through Ag, N, and the P-Ag-P bisector, so that
the (Ag)NO2 plane is far removed from coplanarity with the
AgP2 plane. In both PPh3 and P(o-tolyl)3 arrays, the crystal
packing is of interest (Figure 6c); the PPh3 adduct is a new
AgX:EPh3 (1:2) unsolvated mononuclear type (cf. Table 3
of ref 39).
In contrast to the preceding, the 1:2 adduct of silver(I)
nitrate with triphenylarsine, 13, is binuclear, essentially an
aggregate of a pair of [Ag(O2N)(AsPh3)2] arrays with one
of the nitrite oxygen atoms; interestingly the one with the
shorter of the two chelate interactions (which are unsym-
metrical) is the bridging atom. The dimer is centrosymmetric,
one-half of each of two independent dimers, of similar
geometries and conformations (Table 4, Figure 7) making
up the asymmetric unit of the structure. Other unsolvated
binuclear 1:2 coinage metal(I) oxyanion salt/EPh3 adducts
have been described for the combinations AgNO3/PPh3,46,47
AgNO3/AsPh3,20 and CuNO3/AsPh3,47 none of which are
isomorphous with the present, which, curiously, however,
is isomorphous with the AgX/SbPh3 (X ) Cl, Br, I)32 form
and is presented here in that cell and coordinate setting, with
a more rational atom numbering. These MNO2:EPh3 (1:2)
arrays are interesting in their diversity: CuNO3:PPh3 (1:2)48
and CuNO2:PPh3 (1:2)49 are mononuclear and isomorphous,
while AgNO3:PPh3 (1:2) (benzene50 and toluene51 solvates)
are mononuclear and isomorphous, but of a different crystal-
line form. All are of the form [M(O2N(O))(PPh3)2], the
oxyanion chelating. AgNO3:PPh3 (1:2) also exists in two
different binuclear forms, one triclinic,46 with an isomorphous
E ) As analogue,20 and the other orthorhombic,47 while
CuNO3:AsPh3 (1:2) (binuclear) is of a different monoclinic
type,52 all of these being unsolvated. These binuclear types
again exhibit different forms: in the orthorhombic phase,47
the dimer is bound by a four-membered ring, the oxyanions
bridging the two metal atoms cleanly through a single oxygen
each, [(Ph3E)2M(µ-ONO2)M(EPh3)2] (although the other
(48) (a) Messmer, G. G.; Palenik, G. J. Inorg. Chem. 1969, 8, 2750-2754.
(b) Bowmaker, G. A.; Boyd, S. E.; Hanna, J. V.; Hart, R. D.; Healy,
P. C.; Skelton, B. W.; White, A. H. J. Chem. Soc., Dalton Trans.
2002, 2722-2730.
(49) Halfen, J. A.; Tolman, W. B. Acta Crystallogr., Sect. C 1995, 51,
215-217.
(50) Harker, C. S. W.; Tiekink, E. R. T. Acta Crystallogr., Sect. C 1995,
45, 1815-1817.
(51) Ng, S. W.; Othman, A. H. Acta Crystallogr., Sect. C 1997, 53, 1396-
1400.
(52) Bowmaker, G. A.; Hart, R. D.; Kildea, J. D.; de Silva, E. N.; Skelton,
B. W.; White, A. H. Aust. J. Chem. 1997, 50, 605-619 (corrigen-
dum: Bowmaker, G. A.; Hart, R. D.; Kildea, J. D.; de Silva, E. N.;
Skelton, B. W.; White, A. H. Aust. J. Chem. 1998, 51, 90).
(46) Barron, P. F.; Dyason, J. C.; Healy, P. C.; Engelhardt, L. M.; Skelton,
B. W.; White, A. H. J. Chem. Soc., Dalton Trans. 1986, 1965-1970.
(47) Jones, P. G. Acta Crystallogr., Sect. C 1993, 49, 1148-1150.
6644 Inorganic Chemistry, Vol. 41, No. 25, 2002

-
Variable Coordination Modes of NO2
Figure 9. Topologies found for the AgNO2:ER3 adducts: (a) compound
5; (b) compounds 2, 6, and 12; (c) compounds 14 and 16; (d) compound
13; (e) compound 11; (f) compounds 1 and 15.
In both forms, one molecule (with solvent, as appropriate),
devoid of crystallographic symmetry, comprises the asym-
metric unit of each structure; relevant geometries of the
substrates are given in Table 5 and the molecules depicted
in Figure 8. Of particular interest is the close comparison
possible between the unsolvated isomorphous AgX:SbPh3
(1:3) arrays; cf. that for AgX:Pcy3 (1:2) above, X ) O,O′-
NO2,NO3, in both cases, wherein, consistently, the nitrite
behaves as a consistently stronger O,O′-chelate. Despite
similar O-N-O angles in each pair, Ag-O are shorter in
the nitrite complexes, with corresponding lengthening of
Ag-E and conspicuous diminution of the E-Ag-E angles.
Conclusion
Aggregation of triorganophosphines, -arsines, and -stibines
with silver(I) nitrite has been investigated in the solid state
by single-crystal X-ray diffraction and in solution by
electrospray ionization mass spectrometry (ESI-MS). In the
solid state, topology (Figure 9) is found to depend on the
reaction conditions (mainly ligand-to-metal ratio) and on the
electronic and steric features of the P-donor ligand. For
example sterically hindered ligands such as P(o-tolyl)3 and
Pcy3 yield only mononuclear 1:1 or 1:2 Ag:PR3 adducts,
whereas EPh3 donors (E ) P, As, or Sb) form also 1:4 Ag:
PR3 adducts or di- or polynuclear complexes in which silver
atoms are bridged by NO2- ligands. Significant deformation
of the silver(I) coordination environments are observed as a
function of the Tolman cone angle. The aggregation behavior
is most strongly dependent on the ligand-to-metal ratio and
the solvent employed and to a lesser degree on the coun-
terion. For the 1:3 and 1:4 adducts investigated, aggregation
of the P-donor ligand is significantly disrupted in acetonotrile
at concentrations of approximately 10-3 M. Aggregates
containing a single silver atom dominate significantly over
adducts of higher nuclearity. On the basis of the negative
ESI-MS spectra, it is proposed that in solution the NO2- also
coordinates to a silver(I) ion.
Figure 8. Projections of single molecules of (a) AgNO2:AsPh3 (1:3) (14)
(in its bis(acetonitrile) solvate). (b) AgNO2:SbPh3 (1:3) (16).
oxygens may be viewed as distant chelates interacting
symmetrically to either side), as also is the monoclinic
phase,52 but, in the examples of the triclinic form,42,46
a
second oxygen atom of each anion chelates the metal, as is
also the case in the present, its isomorphous parallels32 being
irrelevant since the bridges are single atoms (halides).
Adducts of the form AgNO2:EPh3 (1:3) are defined herein
for E ) As, Sb, the E ) P adduct, regrettably, not yet being
accessed. The two arrays described herein are of types
already described. The E ) As adduct, 14, is of the common
triclinic solvated form43 (this time as a bis(acetonitrile)
solvate) for which the cell and coordinate setting of CuCl:
SbPh3 (1:3). CHCl333 has been adopted by us as archetypical;
other oxyanion arrays have also been defined for this form:
nitrates as unidentates42,53 and an acetate51 as a bidentate.
The E ) Sb adduct42 is unsolvated and corresponds to the
common monoclinic P21/n form, the cell and coordinate
settings of the AgI:PPh3 (1:3) array54 taken as archetypical.
Acknowledgment. We thank the University of Camerino
and CARIMA Foundation for financial help.
Supporting Information Available: X-ray crystallographic
files, in CIF format, for the structure determinations of 1, 2, 5, 6,
and 11-16. This material is available free of charge via the Internet
at http:/ /pubs.acs.org.
(53) Bowmaker, G. A.; Hart, R. D.; White, A. H. Aust. J. Chem. 1997, 50,
567-576 (corrigendum: Bowmaker, G. A.; Hart, R. D.; White, A.
H. Aust. J. Chem. 1998, 51, 90).
(54) Engelhardt, L. M.; Healy, P. C.; Patrick, V. A.; White, A. H. Aust. J.
Chem. 1987, 40, 1873-1880.
IC020375G
Inorganic Chemistry, Vol. 41, No. 25, 2002 6645