Structural variations and spectroscopic properties of luminescent mono- and multinuclear silver(I) and copper(I) complexes bearing phosphine and cyanide ligands

Article abstract of DOI:10.1021/ic048876k

Reaction of equimolar amounts of AgCN and PCy₃ gave the polymer [(Cy₃P)Ag(NCAgCN)]∞ (1), whereas employment of excess PCy ₃ yielded the discrete compound [(Cy₃P) ₂Ag(NCAgCN)] (2). Reacting bis(dicyclohexylphosphino)-methane (dcpm) with AgCN in 1:1 and 1:2 molar ratios gave two crystalline forms, namely [Ag₂(μ-dcpm)₂][Ag-(CN)₂]₂· (CH₃OH)₂ (3a·(CH₃OH)₂) and [Ag₂(μ-dcpm)₂][Ag(CN)₂]₂ (3b), respectively. The similar reaction of CuCN with PCy₃ afforded the polymeric compound [{(Cy₃P)Cu(CN)}₃]∞ (4), whereas treatment of CuCN with dcpm gave [Cu₂(μ-dcpm)₂(CN) ₂] (5). Employment of diphosphine ligands with longer -(CH ₂)_n- spacers, such as 1,2-bis-(dicyclohexylphosphino) ethane (dcpe, n = 2) and 1,3-bis(diphenylphosphino)propane (dppp, n = 3), in reactions with [Cu(CH₃CN)₄]PF₆ and KCN afforded the macrocylic compounds [{Cu(dcpe)}₂(CN)(μ-dcpe)]PF₆ (6(PF₆)) and [{Cu(dppp)}₃(CN)₂(μ-dppp)] PF₆ (7(PF₆)), respectively. The hexanuclear complex [Cu(CN)(PCy₃)]₆ (8) was obtained by reacting CuCN with PCy₃ in the presence of sodium pyridine-2-thiolate. The UV-vis absorption spectrum of 1 in acetonitrile displays a weak shoulder at 245 nm (ε = 350 dm³ mol^-1 cm^-1). For 3a, 3b, and 5, the intense absorption bands at λ_max = 257-276 nm with ε values of (1.73-1.80) × 10⁴ dm³ mol ^-1 cm^-1 are assigned to [ndσ* → (n + 1)pσ] transitions. Complexes 3a and 3b emit at λ_max = 365 nm in CH₃CN (quantum yield ～6 × 10^-3, lifetime ～0.2 μs). The solid-state emission of 5 (λ_max = 470 and 488 nm at 298 and 77 K) is red-shifted in energy from that of 4 (λ_max = 401 and 405 nm at 298 and 77 K, respectively). In 77 K MeOH/EtOH (1:4) glassy solution, complexes 4-8 display intense emission with λ_max at 382-416 nm, which is assigned to the [3d → (4s, 4p)] triplet excited state.

Full text of DOI:10.1021/ic048876k

Inorg. Chem. 2005, 44, 1511−1524
Structural Variations and Spectroscopic Properties of Luminescent
Mono- and Multinuclear Silver(I) and Copper(I) Complexes Bearing
Phosphine and Cyanide Ligands
Yong-Yue Lin,†,‡ Siu-Wai Lai,*,† Chi-Ming Che,*,† Wen-Fu Fu,†,‡ Zhong-Yuan Zhou,§ and Nianyong Zhu†
Department of Chemistry and HKU-CAS Joint Laboratory on New Materials, The UniVersity of
Hong Kong, Pokfulam Road, Hong Kong, Department of Chemistry, Yunnan Normal UniVersity,
Kunming, 650092 Yunnan, P. R. China, and Department of Applied Biology and Chemical
Technology, The Hong Kong Polytechnic UniVersity, Hunghom, Hong Kong
Received August 16, 2004
Reaction of equimolar amounts of AgCN and PCy3 gave the polymer [(Cy3P)Ag(NCAgCN)]∞ (1), whereas employment
of excess PCy3 yielded the discrete compound [(Cy3P)2Ag(NCAgCN)] (2). Reacting bis(dicyclohexylphosphino)-
methane (dcpm) with AgCN in 1:1 and 1:2 molar ratios gave two crystalline forms, namely [Ag2(
(CN)2]2 (CH3OH)2 (3a (CH3OH)2) and [Ag2( -dcpm)2][Ag(CN)2]2 (3b), respectively. The similar reaction of CuCN
with PCy3 afforded the polymeric compound [ (Cy3P)Cu(CN) (4), whereas treatment of CuCN with dcpm gave
[Cu2( -dcpm)2(CN)2] (5). Employment of diphosphine ligands with longer
(dicyclohexylphosphino)ethane (dcpe, n 2) and 1,3-bis(diphenylphosphino)propane (dppp, n
with [Cu(CH3CN)4]PF6 and KCN afforded the macrocylic compounds [ Cu(dcpe) 2(CN)( -dcpe)]PF6 (6(PF6)) and
Cu(dppp) 3(CN)2( -dppp)]PF6 (7(PF6)), respectively. The hexanuclear complex [Cu(CN)(PCy3)]6 (8) was obtained
µ-dcpm)2][Ag-
‚
‚
µ
{
} ]
3 ∞
µ
−
(CH2)n
−
spacers, such as 1,2-bis-
3), in reactions
)
)
{
}
µ
[{
}
µ
by reacting CuCN with PCy3 in the presence of sodium pyridine-2-thiolate. The UV
−
vis absorption spectrum of 1
1
in acetonitrile displays a weak shoulder at 245 nm (ꢀ ) 350 dm3 mol- cm-1). For 3a, 3b, and 5, the intense
1
1
absorption bands at λmax
[nd (n 1)p ] transitions. Complexes 3a and 3b emit at λmax
10-3, lifetime
0.2 s). The solid-state emission of 5 (λmax 470 and 488 nm at 298 and 77 K) is red-shifted in
energy from that of 4 (λmax 401 and 405 nm at 298 and 77 K, respectively). In 77 K MeOH/EtOH (1:4) glassy
solution, complexes 4 8 display intense emission with λmax at 382 416 nm, which is assigned to the [3d (4s,
4p)] triplet excited state.
)
257−276 nm with
ꢀ
values of (1.73−1.80)
×
104 dm3 mol- cm- are assigned to
σ
*
f
+
σ
)
365 nm in CH3CN (quantum yield 6 ×
∼
∼
µ
)
)
−
−
f
Introduction
nuclearities of coordination polymers or molecular ensembles
are often dictated by parameters such as stoichiometry of
In the design and synthesis of molecular functional
materials, transition-metal coordination using cyanometallate1-3
and cyanide4 as building blocks are becoming increasingly
prevalent, and the judicious employment of ancillary ligands
with different geometric constraints can afford supramolecu-
lar frameworks with diverse structures.5,6 The structures and
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* Authors to whom correspondence should be addressed. Email: cmche@
hku.hk (C.M.C.); swlai@hku.hk (S.W.L.). Fax: +852 2857 1586 (C.M.C.).
† The University of Hong Kong.
‡ Yunnan Normal University.
§ The Hong Kong Polytechnic University.
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Ohkawa, H. Coord. Chem. ReV. 2000, 198, 313-328. (c) Moulton, B.;
Zaworotko, M. J. Chem. ReV. 2001, 101, 1629-1658. (d) Niel, V.;
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10.1021/ic048876k CCC: $30.25
Published on Web 01/22/2005
© 2005 American Chemical Society
Inorganic Chemistry, Vol. 44, No. 5, 2005 1511

Lin et al.
reactants,7,8 steric properties of ancillary ligands,6,9 and
presence of solvate or anion9,10 during crystallization pro-
cesses. Other subtle interactions, such as metallophilicity3,11
and π-π stacking,12 may also play a role in controlling the
supramolecular architecture.
Here we describe the structures of coordination polymers
of Ag(I) and Cu(I) with cyanometallate or cyanide ions as
bridging ligands and tricyclohexylphosphine (PCy3) as the
“capping” ligand. We also report the syntheses of di-, tri-,
and hexanuclear assemblies with [M2(P∩P)2]2+ (M ) Cu and
Ag; P∩P ) bridging diphosphine), [Cu2(P∩P)(µ-CN)]+, [Cu3-
(P∩P)(µ-CN)2]+, and [Cu6(µ-CN)6] core units, respectively.
Their photophysical properties were examined, and com-
parisons with the respective mononuclear counterparts were
made to probe and validate the presence and consequence
of metal-metal interactions.
In the context of increasing structural dimensionality and
imparting intriguing photoluminescent characteristics to
metal-containing assemblies, the employment of closed-shell
d10 metal ions, including Cu(I), Ag(I), and Au(I), has long
been demonstrated via weak metal-metal13 and metal-
ligand14 interactions. The coordinatively unsaturated dicyano-
aurates(I) and -argentates(I) are good candidates for exam-
ining d10-d10 interactions in the ground15 and excited states,16
and such interactions could lead to the formation of
luminescent metal-metal-bonded excimers and metal-
ligand exciplexes. For example, the two-coordinate *Cu(CN)2-,
formed upon UV irradiation, was reported to associate with
halide ions to give a long-lived, highly luminescent exci-
plex.17
Experimental Section
General Procedures. All starting materials were used as
received. [Cu(CH3CN)4]PF6 was prepared by literature method.18
Dichloromethane for photophysical studies was washed with
concentrated sulfuric acid, 10% sodium hydrogen carbonate and
water, dried by calcium chloride, and distilled over calcium hydride.
Acetonitrile for photophysical measurements was distilled over
potassium permanganate and calcium hydride. All other solvents
were of analytical grade and purified according to conventional
methods.19 All reactions were carried out using standard Schlenk
techniques with essential exclusion of light; for instance, reaction
flasks were wrapped with opaque foil, filtration and evaporation
were done under prevention of direct irradiation of light, recrys-
tallization was carried out in the absence of light, and products
were stored in amber glass vials with wrappings of opaque foil.
Samples were dried under high vacuum prior to elemental analysis
and NMR spectroscopic measurements.
Fast atom bombardment (FAB) mass spectra were obtained on
a Finnigan Mat 95 mass spectrometer with a 3-nitrobenzyl alcohol
matrix, whereas electrospray mass spectra were obtained on a LCQ
quadrupole ion trap mass spectrometer. 1H (500 MHz) and 31P (202
MHz) NMR measurements were performed on a DPX 500 Bruker
FT-NMR spectrometer with chemical shifts (in ppm) relative to
tetramethylsilane (1H) and H3PO4 (31P) as references. Elemental
analysis was performed by the Institute of Chemistry at the Chinese
Academy of Sciences, Beijing. Infrared spectra were recorded on
a Bio-Rad FT-IR spectrophotometer. UV-vis spectra were recorded
on a Perkin-Elmer Lambda 19 UV/vis spectrophotometer.
Emission and Lifetime Measurements. Steady-state emission
spectra were recorded on a SPEX 1681 Fluorolog-2 model F111AI
spectrophotometer. Solution samples for measurements were de-
gassed with at least four freeze-pump-thaw cycles. Low-temper-
ature (77 K) emission spectra for glasses and solid-state samples
were recorded in 5 mm diameter quartz tubes, which were placed
in a liquid nitrogen Dewar equipped with quartz windows. The
emission spectra were corrected for monochromator and photo-
multiplier efficiency and for xenon lamp stability.
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Emission lifetime measurements were performed with a Quanta
Ray DCR-3 pulsed Nd:YAG laser system (pulse output 266 nm, 8
ns). The emission signals were detected by a Hamamatsu R928
photomultiplier tube and recorded on a Tektronix TDS 350
oscilloscope. Errors for λ values ((1 nm), τ ((10%), Φ ((10%)
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2000, 39, 4084-4088. (d) Fu, W.-F.; Chan, K.-C.; Cheung, K.-K.;
Che, C.-M. Chem.sEur. J. 2001, 7, 4656-4664. (e) Che, C.-M.; Lai,
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1512 Inorganic Chemistry, Vol. 44, No. 5, 2005

Ag(I) and Cu(I) Complexes with Phosphine and Cyanide Ligands
were estimated. The emission quantum yields were determined
using the method of Demas and Crosby20 with quinine sulfate in
degassed 0.1 N sulfuric acid as a standard reference solution (Φr
) 0.546).
refluxed under an argon atmosphere for 6 h and the solution turned
pale green. Upon cooling to room temperature, the mixture was
filtered, and the volume of filtrate was reduced to ∼5 mL; addition
of diethyl ether gave a white solid, which was collected by filtration
and dried. Recrystallization by slow diffusion of diethyl ether into
a dichloromethane solution afforded colorless crystals: yield 0.20
g, 54%. Anal. Calcd for C57H99N3P3Cu3: C, 61.68; H, 8.99; N,
3.79. Found: C, 61.57; H, 9.01; N, 3.86. FAB-MS: m/z 624
[(Cy3P)2Cu]+, 712 [(Cy3P)2Cu2(CN)]+, 803 [(Cy3P)2Cu3(CN)2]+,
892 [(Cy3P)2Cu4(CN)3]+, 981 [(Cy3P)2Cu5(CN)4]+, 1072 [(Cy3P)2-
Cu6(CN)5]+, 1161 [(Cy3P)2Cu7(CN)6]+, 1250 [(Cy3P)2Cu8(CN)7]+,
Synthesis. [(Cy3P)Ag(NCAgCN)]∞, 1. To a stirred solution of
tricyclohexylphosphine, PCy3, (0.21 g, 0.75 mmol) in dichlo-
romethane (30 mL) in the dark at 298 K was added AgCN (0.10 g,
0.75 mmol). The resultant suspension was refluxed under an argon
atmosphere for 24 h, and the solution turned pale yellow. Upon
cooling to room temperature, the mixture was filtered, and the
volume of filtrate was reduced to ∼5 mL. Addition of diethyl ether
gave a white solid, which was collected by filtration and dried.
Recrystallization by slow diffusion of diethyl ether into a dichlo-
romethane solution gave colorless crystals: yield 0.12 g, 58%. Anal.
Calcd for C20H33N2PAg2: C, 43.82; H, 6.07; N, 5.11. Found: C,
43.52; H, 6.16; N, 4.96. FAB-MS: m/z 387 [(Cy3P)Ag]+, 522
[(Cy3P)Ag2(CN)]+, 670 [(Cy3P)(C)Ag3(CN)2]+, 683 [(Cy3P)Ag3-
(CN)3]+, 802 [(Cy3P)(C)Ag4(CN)3]+, 817 [(Cy3P)Ag4(CN)4]+, 937
[(Cy3P)(C)Ag5(CN)4]+, 1070 [(Cy3P)(C)Ag6(CN)5]+. 1H NMR
(CDCl3): δ 1.19-1.35 (m, 15H, Cy), 1.73-1.76 (m, 3H, Cy), 1.86
(m, 15H, Cy). 31P{1H} NMR (CDCl3): δ 41.15 (m, J [Ag107-P]
1
1341 [(Cy3P)2Cu9(CN)8]+, 1430 [(Cy3P)2Cu10(CN)9]+. H NMR
(CDCl3): δ 1.21-1.46 (m, 45H), 1.72-1.93 (m, 54H). 31P{1H}
NMR (CDCl3): δ 12.99. IR (KBr): ν 2123 (CtN) cm-1
.
[Cu2(µ-dcpm)2(CN)2], 5. To a stirred solution of CuCN (0.045
g, 0.50 mmol) in dichloromethane (30 mL) was added dcpm (0.20
g, 0.49 mmol). The resultant suspension was refluxed under an
argon atmosphere for 16 h. The mixture was cooled to room
temperature and filtered, and the volume of the filtrate was reduced
to ∼5 mL. Addition of diethyl ether afforded a white precipitate,
and recrystallization by diffusion of diethyl ether into a dichlo-
romethane solution gave colorless crystals: yield 0.12 g, 48%. Anal.
Calcd for C52H92N2P4Cu2: C, 62.69; H, 9.31; N, 2.81. Found: C,
63.11; H, 9.58; N, 3.02. FAB-MS: m/z 560 [(dcpm)Cu2(CN)]+,
651 [(dcpm)Cu3(CN)2]+, 740 [(dcpm)Cu4(CN)3]+, 968 [(dcpm)2Cu2-
(CN)]+, 1059 [(dcpm)2Cu3(CN)2]+, 1148 [(dcpm)2Cu4(CN)3]+. 1H
NMR (CDCl3): δ 1.22-1.48 (m, 40H, Cy), 1.71-2.17 (m, 52H,
Cy and CH2). 31P{1H} NMR (CDCl3): δ 6.46. IR (KBr): ν 2127
) 508 Hz, J [Ag109-P] ) 580 Hz). IR (KBr): ν 2154 (CtN) cm-1
.
[(Cy3P)2Ag(NCAgCN)], 2. The procedure for 1 was adopted,
except for using a 2:1 molar ratio of PCy3 to AgCN, and a colorless
crystalline solid was afforded: yield 0.19 g, 61%. Anal. Calcd for
C38H66N2P2Ag2: C, 55.08; H, 8.03; N, 3.38. Found: C, 55.14; H,
8.01; N, 2.87. FAB-MS: m/z 667 [(Cy3P)2Ag]+, 802 [(Cy3P)2Ag2-
(CN)]+, 935 [(Cy3P)2Ag3(CN)2]+, 1070 [(Cy3P)2Ag4(CN)3]+, 1203
(CtN) cm-1
.
1
[(Cy3P)2Ag5(CN)4]+. H NMR (CDCl3): δ 1.20-1.37 (m, 30H,
Cy), 1.74-1.76 (m, 6H, Cy), 1.86 (m, 30H, Cy). 31P{1H} NMR
(CDCl3): δ 41.68 (m, J [Ag107-P] ) 524 Hz, J [Ag109-P] ) 598
[{Cu(dcpe)}2(CN)(µ-dcpe)]PF6, 6(PF6). To a stirred solution
of [Cu(CH3CN)4]PF6 (0.18 g, 0.48 mmol) in methanol (15 mL)
was added 1,2-bis(dicyclohexylphosphino)ethane, dcpe (0.31 g, 0.73
mmol). The white suspension was stirred until a clear solution was
obtained. To this mixture was added KCN (41 mg, 0.63 mmol) to
yield a white solid, which was dissolved upon addition of
dichloromethane (10 mL) and stirred for 10 h at 298 K. The
resultant white suspension was evaporated to dryness, and the solid
was washed with a small amount of CH2Cl2 (∼2 mL) and filtered.
Recrystallization by slow diffusion of diethyl ether into a dichlo-
romethane solution yielded colorless crystals: yield 0.14 g, 37%.
Anal. Calcd for C79H144NF6P7Cu2: C, 60.60; H, 9.27; N, 0.89.
Found: C, 59.77; H, 9.15; N, 0.87. FAB-MS: m/z 998 [(dcpe)2Cu2-
(CN)]+, 1088 [(dcpe)2Cu3(CN)2]+, 1177 [(dcpe)2Cu4(CN)3]+, 1268
[(dcpe)2Cu5(CN)4]+, 1357 [(dcpe)2Cu6(CN)5]+, 1447 [(dcpe)2Cu7-
(CN)6]+. ESI-MS: m/z 907.9 [(dcpe)2Cu]+, 998.5 [(dcpe)2Cu2-
(CN)]+, 1420.0 [M+], 1508.9 [(dcpe)3Cu3(CN)2]+. 1H NMR
(CDCl3): δ 1.19-1.39 (m, 60H, Cy), 1.70-1.98 (m, 84H, Cy and
Hz). IR (KBr): ν 2122 (CtN) cm-1
.
[Ag2(µ-dcpm)2][Ag(CN)2]2‚(CH3OH)2, 3a‚(CH3OH)2. To a
stirred solution of bis(dicyclohexylphosphino)methane, dcpm (0.42
g, 1.03 mmol), in dichloromethane (30 mL) in the dark at 298 K
was added AgCN (0.14 g, 1.05 mmol). The resultant suspension
was stirred under an argon atmosphere for 3 h, and the solution
turned pale yellow. The mixture was filtered, and the volume of
filtrate was reduced to ∼5 mL; addition of diethyl ether gave a
white solid, which was collected by filtration and dried. Recrys-
tallization by slow diffusion of diethyl ether into a methanol/
dichloromethane (1:3) solution yielded colorless crystals: yield 0.20
g, 57%. Anal. Calcd for C54H92N4P4Ag4: C, 47.95; H, 6.85; N,
4.14. Found: C, 48.25; H, 6.89; N, 3.80. FAB-MS: m/z 1059 [M+
- Ag2(CN)3], 1192 [M+ - Ag(CN)2], 1327 [M+ - CN], 1461 [M+
+ Ag], 1595 [M+ + Ag2(CN)], 1728 [M+ + Ag3(CN)2], 1863 [M+
+ Ag4(CN)3]. 1H NMR (CDCl3): δ 1.23-1.46 (m, 40H), 1.79 (m,
8H), 1.88-1.99 (m, 44H). 31P{1H} NMR (CDCl3): δ 25.25 (d, J
CH2). IR (Nujol): ν 2108 (CtN) cm-1 31P{1H} NMR: See Results
.
and Supporting Information.
) 458 Hz). IR (KBr): ν 2102, 2135 (CtN) cm-1
.
[Ag2(µ-dcpm)2][Ag(CN)2]2, 3b. The procedure for 3a‚(CH3OH)2
was adopted using a 1:2 molar ratio of dcpm to AgCN and
recrystallization by slow diffusion of diethyl ether into a dichlo-
romethane solution, which afforded a colorless crystalline solid:
yield 0.26 g, 74%. Anal. Calcd for C54H92N4P4Ag4: C, 47.95; H,
6.85; N, 4.14. Found: C, 48.01; H, 7.06; N, 3.79. FAB-MS: m/z
1059 [M+ - Ag2(CN)3], 1194 [M+ - Ag(CN)2], 1327 [M+ - CN],
1460 [M+ + Ag], 1595 [M+ + Ag2(CN)], 1728 [M+ + Ag3(CN)2],
1861 [M+ + Ag4(CN)3]. 1H NMR (CDCl3): δ 1.21-1.45 (m, 40H),
1.81 (m, 8H), 1.87-1.99 (m, 44H). 31P{1H} NMR (CDCl3): δ 25.20
[{Cu(dppp)}3(CN)2(µ-dppp)]PF6, 7(PF6). The procedure for
6(PF6) was adopted using 1,3-bis(diphenylphosphino)propane, dppp
(0.27 g, 0.65 mmol), and recrystallization by slow diffusion of
diethyl ether into an acetonitrile/dichloromethane (1:3) solution
afforded colorless crystals: yield 0.11 g, 34%. Anal. Calcd for
C
110H104N2F6P9Cu3: C, 64.85; H, 5.14; N, 1.37. Found: C, 64.24;
H, 5.15; N, 1.45. FAB-MS: m/z 978 [(dppp)2Cu2(CN)]+, 1067
[(dppp)2Cu3(CN)2]+, 1156 [(dppp)2Cu4(CN)3]+, 1247 [(dppp)2Cu5-
(CN)4]+, 1336 [(dppp)2Cu6(CN)5]+, 1391 [(dppp)3Cu2(CN)]+, 1480
[(dppp)3Cu3(CN)2]+, 1569 [(dppp)3Cu4(CN)3]+, 1892 [M+]. ESI-
MS: m/z 887.1 [(dppp)2Cu]+, 977.9 [(dppp)2Cu2(CN)]+, 1068.6
[(dppp)2Cu3(CN)2]+, 1389.7 [(dppp)3Cu2(CN)]+, 1478.7 [(dppp)3Cu3-
(d, J ) 455 Hz). IR (KBr): ν 2140 (CtN) cm-1
.
[{(Cy3P)Cu(CN)}3]∞, 4. To a stirred solution of PCy3 (0.29 g,
1.03 mmol) in dichloromethane (30 mL) in the dark at 298 K was
added CuCN (0.09 g, 1.00 mmol). The resultant suspension was
(20) Demas, J. N.; Crosby, G. A. J. Phys. Chem. 1971, 75, 991-1024.
Inorganic Chemistry, Vol. 44, No. 5, 2005 1513

Lin et al.
(CN)2]+, 1892.5 [M+]. 1H NMR (CD2Cl2): δ 1.40-1.94 (m, 14H,
CH2), 2.31-2.43 (m, 10H, CH2), 6.67-7.71 (m, 80H, Ph). IR
(Nujol): ν 2116 (CtN) cm-1 31P{1H} NMR: See Results and
.
Supporting Information.
[Cu(CN)(PCy3)]6, 8. The procedure for [Cu(CN)(PPh3)2]64d was
adopted using CuCN (0.046 g, 0.51 mmol), PCy3 (0.28 g, 1.00
mmol), and sodium pyridine-2-thiolate (0.11 g, 0.83 mmol) to afford
a pale-yellow solid: yield 0.12 g, 63%. Anal. Calcd for C114H198N6P6-
Cu6: C, 61.68; H, 8.99; N, 3.79. Found: C, 60.89; H, 9.01; N,
3.72. FAB-MS: m/z 1072 [(Cy3P)2Cu6(CN)5]+, 1161 [(Cy3P)2Cu7-
(CN)6]+, 1250 [(Cy3P)2Cu8(CN)7]+, 1341 [(Cy3P)2Cu9(CN)8]+, 1430
[(Cy3P)2Cu10(CN)9]+, 1519 [(Cy3P)2Cu11(CN)10]+, 1608 [(Cy3P)2-
1
Cu12(CN)11]+, 1699 [(Cy3P)2Cu13(CN)12]+. H NMR (CDCl3): δ
1.20-1.40 (m, 90H), 1.71-1.88 (m, 108H). 31P{1H} NMR
(CDCl3): δ 12.17 (broad). IR (KBr): ν 2124 (CtN) cm-1
.
X-ray Crystallography. Crystals of 1-8 were obtained by slow
diffusion of diethyl ether into dichloromethane or CH3OH/CH2Cl2
(1:3) or CH3CN/CH2Cl2 (1:3) solutions. Crystal data and details of
data collection and refinement are summarized in Table 1.
Data for complexes 2, 3a‚(CH3OH)2, 3b, and 4 were collected
at 294 K on a Bruker CCD Area Detector diffractometer by the æ
and ω scan technique using graphite-monochromated Mo KR
radiation (λ ) 0.71073 Å). For these complexes, the coordinates
of the metal atoms were determined by direct methods, and the
remaining non-hydrogen atoms were located from successive
Fourier difference syntheses. The structures were refined by full-
matrix least-squares technique with anisotropic thermal parameters
for all the non-hydrogen atoms. The calculations were performed
on a COMPUCON PC/586 computer with the Bruker AXS
SHELXTL/PC program package.21 For 2, a crystallographic asym-
metric unit consists of one molecule. The crystallographic asym-
metric units of 3a‚(CH3OH)2 and 3b consist of half of one molecule,
while the former contains one methanol molecule as solvent of
crystallization. For 4, a crystallographic asymmetric unit consists
of one [{(Cy3P)Cu(CN)}3] repeating group.
Diffraction experiments for 1, 5‚(CH2Cl2)2, 6(PF6)‚Et2O,
7(PF6)‚0.5CH3CN, and 8‚(Et2O)2 were performed at 301 K on an
MAR diffractometer with graphite-monochromatized Mo KR
radiation (λ ) 0.71073 Å). For 1, the structure was solved by heavy-
atom Patterson methods22 and expanded using Fourier techniques.23
Refinement of structures was performed by full-matrix least-squares
technique using the software package TeXsan24 on a Silicon
Graphics Indy computer. The non-hydrogen atoms were refined
anisotropically. Hydrogen atoms were included but not refined. The
structures of 5‚(CH2Cl2)2, 6(PF6)‚Et2O, 7(PF6)‚0.5CH3CN, and 8‚
(Et2O)2 were solved by direct methods (SIR97),25 and refinement
of structures was performed by full-matrix least-squares technique
using SHELXL-9721 program package on a PC. For 1, a crystal-
lographic asymmetric unit consists of one formula unit. The
structure is polymeric with Ag(2*) at 1 - x, 1/2 + y, 1/2 - z bonded
(21) Sheldrick, G. M. SHELX 97, Programs for Crystal Structure Analysis;
University of Go¨ttingen: Go¨ttingen, Germany, 1997.
(22) Beurskens, P. T.; Admiraal, G.; Beurskens, G.; Bosman, W. P.; Garcia-
Granda, S.; Gould, R. O.; Smits, J. M. M.; Smykalla, C. PATTY, The
DIRDIF Program System: Technical Report of the Crystallography
Laboratory; University of Nijmegen: The Netherlands, 1992.
(23) Beurskens, P. T.; Admiraal, G.; Beurskens, G.; Bosman, W. P.; de
Gelder, R.; Israel, R.; Smits, J. M. M. The DIRDIF-94 Program
System: Technical Report of the Crystallography Laboratory; Uni-
versity of Nijmegen: The Netherlands, 1994.
(24) TeXsan: Crystal Structure Analysis Package; Molecular Structure
Corporation: The Woodlands, Texas, 1985 and 1992.
(25) Altomare, A.; Burla, M. C.; Camalli, M.; Cascarano, M.; Giacovazzo,
C.; Guagliardi, A.; Moliterni, A. G. G.; Polidori, G.; Spagna, R. SIR97.
J. Appl. Crystallogr. 1998, 32, 115.
1514 Inorganic Chemistry, Vol. 44, No. 5, 2005

Ag(I) and Cu(I) Complexes with Phosphine and Cyanide Ligands
Scheme 1. Synthesis of 1-3a,b
stoichiometric ratio of 1:1 and 2:1 gave 3a and 3b,
respectively (Scheme 1), and both structures comprise the
same [Ag2(µ-dcpm)2]2+ core with minor structural deviations
(see Scheme 1). The IR spectrum of 3a displays two weak
peaks at 2102 and 2135 cm-1, which are consistent with two
different cyanide coordination modes for the [NCAgCN]-
units. The IR spectrum of 3b shows one strong peak at 2140
cm-1, indicating that the two cyanide groups are in a similar
chemical environment without coordination to the [Ag2(µ-
dcpm)2]2+ core. The 31P{1H} NMR spectra of 3a and 3b
show a similar broad doublet at ∼25.2 ppm with coupling
constants (J) of ∼455 Hz. These silver(I) compounds (1-
3a,b) are air-stable in the solid state, but they are stable in
solution for a few days only in the absence of light.
Reaction of PCy3 with CuCN in equal stoichiometry
afforded the polymeric compound [{(Cy3P)Cu(CN)}3]∞ (4)
(Scheme 2). The IR spectrum shows the ν(CtN) stretching
at 2123 cm-1, which is comparable to that of 2122 cm-1
observed for 2. In the 31P{1H} NMR spectrum of 4, a peak
is observed at 12.99 ppm that is significantly downfield from
those of 1 and 2, consistent with Cu(I) to be more electron
rich than Ag(I). The discrete binuclear complex [Cu2(µ-
dcpm)2(CN)2] (5) was obtained by reacting CuCN with dcpm
in an equimolar ratio (Scheme 2), and the structure of the
[Cu2(µ-dcpm)2]2+ core is similar to that of [Ag2(µ-dcpm)2]2+
in 3a and 3b. The employment of diphosphine ligands with
longer -(CH2)n- spacers, namely 1,2-bis(dicyclohexylphos-
phino)ethane (dcpe, n ) 2) and 1,3-bis(diphenylphosphino)-
propane (dppp, n ) 3), in reactions with [Cu(CH3CN)4]PF6
followed by addition of KCN, afforded the ring compounds
[{Cu(dcpe)}2(CN)(µ-dcpe)]PF6 (6(PF6)) and [{Cu(dppp)}3-
(CN)2(µ-dppp)]PF6 (7(PF6)), respectively (Scheme 2). The
hexanuclear compound [Cu(CN)(PCy3)]6 (8) was obtained
by reacting CuCN with PCy3 in the presence of sodium
pyridine-2-thiolate (Scheme 2), a procedure similar to the
preparation of [Cu(CN)(PPh3)2]6.4d These copper(I) com-
plexes (4-8) are air stable in solid and solution.
to C(1) and C(1*) at 1 - x, -1/2 + y, /2 - z bonded to Ag(2) in
1
the nearest neighborhood. For 5‚(CH2Cl2)2, a crystallographic
asymmetric unit consists of half of a formula unit, including one
dichloromethane solvent molecule. All non-H atoms were refined
anisotropically, and H atoms were generated by the SHELXL-97
program. For 6(PF6)‚Et2O, a crystallographic asymmetric unit
consists of one formula unit with one diethyl ether molecule as
solvent of crystallization. Only Cu, P, and cyanide were refined
anisotropically, and other non-hydrogen atoms were located iso-
-
tropically. The anion of PF6 was disordered by rotation along a
F-P-F axis. The cyanide ligand was treated with disorder of C
and N atoms. For 7(PF6)‚0.5CH3CN, one crystallographic asym-
metric unit consists of one formula unit, including half of one
-
acetonitrile solvent molecule and two halves of PF6 anions.
Cyanide ligands were treated with disorder of C and N atoms. For
8‚(Et2O)2, one crystallographic asymmetric unit consists of half of
a formula unit, including one diethyl ether solvent molecule.
Results
Synthesis and Characterization. Schemes 1 and 2 depict
the synthesis of the silver (1-3a,b) and copper (4-8)
compounds studied in this work. Reaction of AgCN and PCy3
in equimolar ratio gave the coordination polymer [(Cy3P)-
Ag(NCAgCN)]∞ (1). Upon altering the molar ratio of PCy3:
AgCN to 2:1, the discrete molecular complex [(Cy3P)2Ag-
(NCAgCN)] (2) was afforded (Scheme 1). The 31P{1H} NMR
spectrum of 1 displays doublets at δ 41.15 with J values of
508 and 580 Hz, whereas those of 2 appear at 41.68 ppm
with J values of 524 and 598 Hz, which are due to 1J(107Ag-
The IR spectra of 5-8 show ν(CtN) stretchings in the
2108-2127 cm-1 range. The 31P{1H} NMR spectrum of 5
displays a peak at 6.46 ppm, whereas that of 6 shows broad
signals in the range of -2.46 and 19.72 ppm. The 31P{1H}
NMR spectrum of 7 in CDCl3 at 40 °C shows two sets of
three peaks as broad singlets at [-3.33, -11.03, -13.34
ppm] and [-8.19, -14.18, -17.27 ppm], respectively. The
integration ratio for each set of three peaks is 1:2:1. In the
31P{1H} NMR spectrum of 7 at 20 °C, couplings were
observed at signals with the chemical shift centered at -3.42
(broad triplet), -8.43 (triplet, J ) 47.4 Hz), -10.98 (doublet,
J ) 35.9 Hz), and -14.29 ppm (doublet, J ) 46.0 Hz). The
31P-31P COSY spectrum of 7 in CD2Cl2 at 25 °C shows
cross peaks at the intersection of -3.50 ppm with -11.24
1
P) and J(109Ag-P) couplings, respectively. In the FT-IR
spectra, the ν(CtN) bands of 1 and 2 occur at 2154 and
2122 cm-1, respectively. This is consistent with the less
electrophilic nature of [(Cy3P)2Ag]+ in 2 compared to that
of [(Cy3P)Ag]+ in 1, if we regard PCy3 as a σ-donor. In
comparison with ν(CtN) of 2135 cm-1 in the free [Ag(CN)2]-
anion,26 the higher ν(CtN) stretching frequency in 1 suggests
that the cyanoargentate ions in 1 behave as bridging linkages
via both cyanide termini. The ancillary PCy3 ligand plays a
role in stabilizing the cyanometallate-directed polymeric
structure of 1.
In the literature, reactions of transition metal halides with
bidentate phosphine ligands (P∩P), such as dppm or dcpm,
in 1:1 stoichiometry were reported to afford compounds with
the [M2(µ-P∩P)2]n+ framework (M ) Re, Mo, Cu, Ag, Au,
Pt, Mn).27 In this work, reacting AgCN with dcpm in
(27) (a) Brown, M. P.; Puddephatt, R. J.; Rashidi, M.; Seddon, K. R. J.
Chem. Soc., Dalton Trans. 1978, 1540-1544. (b) Benner, L. S.; Balch,
A. L. J. Am. Chem. Soc. 1978, 100, 6099-6106. (c) Kubiak, C. P.;
Woodcock, C.; Eisenberg, R. Inorg. Chem. 1980, 19, 2733-2739.
(d) Kubiak, C. P.; Eisenberg, R. J. Am. Chem. Soc. 1980, 102, 3637-
3639. (e) Frew, A. A.; Hill, R. H.; Manojlovic-Muir, L.; Muir, K.
W.; Puddephatt, R. J. J. Chem. Soc., Chem. Commun. 1982, 198-
200.
(26) Penneman, R. A.; Jones, L. H. J. Inorg. Nucl. Chem. 1961, 20, 19-
31.
Inorganic Chemistry, Vol. 44, No. 5, 2005 1515

Lin et al.
Scheme 2. Synthesis of 4-8
ppm and of -8.12 ppm with -14.43 ppm. This coupling
connectivity, together with the multiplicity and integration
ratio of peaks for 7, suggests that two different structural
conformers are in solution; there are two sets of three peaks
in the 31P{1H} NMR spectrum of 7 [-3.42 ppm, broad t,
P(3, 4); -10.98 ppm, d, J ) 35.9 Hz, P(1, 2, 5, 6); -13.22
ppm, s, P(7, 8)] and [-8.43 ppm, t, J ) 47.4 Hz, P(3, 4);
-14.29 ppm, d, J ) 46.0 Hz, P(1, 2, 5, 6); -17.30 ppm, s,
P(7, 8)] (see Figures S2-S5 in the Supporting Information
for details).
Bending of the (Cy3P)Ag-N-C angle (157.2°) from linear-
ity is observed upon coordination of [NCAgCN]- to [(Cy3P)-
Ag]+.
Complex [(Cy3P)2Ag(NCAgCN)] (2) comprises a [(Cy3P)2-
Ag]+ cation coordinated to [NCAgCN]- (Figure 2) to give
a AgP2N trigonal planar geometry. The Ag(1)-N(1) distance
of 2.627(2) Å is longer than the corresponding Ag-N
distances (mean 2.24 Å) in 1. The mean Ag-C distance in
[NCAgCN]- is 2.054 Å, which is comparable to the Ag-C
distance of 2.153(6) Å in [Ag(PCy3)2CN]29 and 2.15(6) Å
in [AgCN]∞.30 The [Ag(CN)2]- ion is coordinated to [(Cy3P)2-
Ag]+ with the C(37)-N(1)-Ag(1) angle of 171.1(2)°,
whereas the geometry of the [Ag(CN)2]- ligand remains close
to linearity. The average Ag-P distance of 2.424 Å in 2
lies in the range of 2.333-2.429 Å reported for [(PR3)2Ag]-
Cl (R ) H, Me, tmpp)31 and is slightly longer than that of
2.38 Å in 1. This could be attributed to the steric effect
In the positive FAB mass spectra, peaks corresponding to
+
cationic species with the formula of [(Cy3P)2Mn(CN)n-1
]
are apparent for 2 (M ) Ag; n ) 1-5), 4 (M ) Cu; n )
1-10), and 8 (M ) Cu; n ) 6-13). Similarly, two cationic
+
species with the formulas of [(dcpm)Cun(CN)n-1
]
and
[(dcpm)2Cun(CN)n-1]+ (n ) 2-4) were detected in the mass
spectrum of 5, whereas for 6, peaks attributable to the
+
32
[(dcpe)2Cun(CN)n-1
]
(n ) 2-7) ions were observed. For
because of the large cone angle (170°) of PCy3 in
7, the FAB mass spectrum shows the molecular ion at m/z
comparison to that of 118, 137, and 145° for trimethyl-,
triethyl-, and triphenylphosphine, respectively.
+
1892 as well as [(dppp)2Cun(CN)n-1
]
(n ) 2-6) and
[(dppp)3Cun(CN)n-1]+ (n ) 2-4). The electrospray ionization
mass spectra of 6 and 7 contain the molecular ion at m/z
1420.0 and 1892.5, respectively. The [(L)2Cun(CN)n-1]+ (L
) dcpe, n ) 1-2 (for 6); L ) dppp, n ) 1-3 (for 7)) and
[(L)3Cun(CN)n-1]+ (L ) dcpe, n ) 3 (for 6); L ) dppp, n )
2-3 (for 7)) species were also detected. These ionic clusters
are commonly observed in the mass spectroscopy of metal-
cyanide complexes.28
Crystal Structures. X-ray structural determinations of 1,
2, 3a, 3b, and 4-8 have been performed (Figures 1-8), and
selected bond lengths and angles are listed in Table 2. The
structure of 1 (Figure 1) consists of alternating [(Cy3P)Ag]+
units with µ-[NCAgCN]- cyanometallate linkers, forming a
one-dimensional zigzag polymeric chain. The three-coordi-
nate silver atoms of the [(Cy3P)Ag]+ units adopt a trigonal
planar geometry and are coordinated to the linear [NCAgCN]-
bridges. The bond angles at these silver atoms [P(1)-Ag-
(1)-N(1), N(1)-Ag(1)-N(2), and P(1)-Ag(1)-N(2)] lie
in the range 100-136°, with the sum approaching 360°. The
Ag-P bonds are coplanar with the plane defined by the
[Ag-NC-Ag-CN-]n zigzag backbone. The mean Ag-N
distance connecting [(Cy3P)Ag]+ units to [NCAgCN]-
bridges is 2.24 Å, which is slightly longer than the Ag-C
distances (mean 2.05 Å) in the [Ag(CN)2]- unit. The
[NCAgCN]- bridges two [(Cy3P)Ag]+ units with a span
length of ∼10.8 Å and remains in a nearly linear geometry.
Crystals of 3a were obtained with two methanol molecules
per unit cell (Figure 3). The structure consists of a cationic
[Ag2(µ-dcpm)2]2+ core with two bridging dcpm ligands in a
chair configuration; the P(2)-Ag(1)-P(1A) angle of 155.80-
(4)° shows significant deviation from linearity, and the P(2)-
Ag(1)-Ag(1A) and P(1A)-Ag(1)-Ag(1A) angles are 92.33-
(3) and 87.83(3)°, respectively. Each of the silver atoms in
[Ag2(µ-dcpm)2]2+ is bound to [NCAgCN]- with an Ag-N
distance of 2.452(4) Å. The N(1)-Ag(1)-Ag(1A) angle of
89.7(1)° is close to 90°, and the two [NCAgCN]- ions extend
in opposite directions. The coordinated [NCAgCN]- anions
remain close to linearity, whereas the C(25)-N(1)-Ag(1)
angle of 153.8(4)° is bent. The intramolecular Ag‚‚‚Ag
distance of 2.8949(7) Å is comparable to those observed in
polynuclear Ag(I) derivatives with proposed d10-d10 inter-
(28) (a) Jennings, K. R.; Kemp, T. J.; Sieklucka, B. J. Chem. Soc., Dalton
Trans. 1988, 2905-2911. (b) Dance, I. G.; Dean, P. A. W.; Fisher,
K. J. Inorg. Chem. 1994, 33, 6261-6269. (c) Chu, I. K.; Shek, I. P.
Y.; Siu, K. W. M.; Wong, W.-T.; Zuo, J.-L.; Lau, T.-C. New J. Chem.
2000, 24, 765-769. (d) Dance, I. G.; Dean, P. A. W.; Fisher, K. J.;
Harris, H. H. Inorg. Chem. 2002, 41, 3560-3569.
(29) Bowmaker, G. A.; Effendy; Harvey, P. J.; Healy, P. C.; Skelton, B.
W.; White, A. H. J. Chem. Soc., Dalton Trans. 1996, 2449-2457.
(30) Bowmaker, G. A.; Kennedy, B. J.; Reid, J. C. Inorg. Chem. 1998, 37,
3968-3974.
(31) Bowmaker, G. A.; Schmidbaur, H.; Kru¨ger, S.; Ro¨sch, N. Inorg. Chem.
1997, 36, 1754-1757.
(32) Hormann-Arendt, A. L.; Shaw, C. F., III. Inorg. Chem. 1990, 29,
4683-4687.
1516 Inorganic Chemistry, Vol. 44, No. 5, 2005

Ag(I) and Cu(I) Complexes with Phosphine and Cyanide Ligands
Table 2. Selected Bond Lengths (Å) and Angles (deg)
complex 1
2.045(7)
1.123(8)
Ag(1)-P(1)
Ag(1)-N(1)
2.380(1)
2.263(5)
Ag(2)-C(2)
N(1)-C(1)
Ag(1)-N(2)
Ag(2)-C(1)
2.207(5)
2.047(6)
N(2)-C(2)
1.124(9)
N(1)-Ag(1)-N(2)
P(1)-Ag(1)-N(1)
100.6(2)
123.4(1)
Ag(2)-C(1)-N(1)
Ag(1)-N(1)-C(1)
176.3(6)
157.2(6)
P(1)-Ag(1)-N(2)
C(1)-Ag(2)-C(2)
135.9(2)
176.0(3)
Ag(2)-C(2)-N(2)
Ag(1)-N(2)-C(2)
173.4(7)
166.2(6)
complex 2
Ag(1)-P(1)
Ag(1)-P(2)
2.4288(8)
2.4196(8)
Ag(2)-C(37)
Ag(2)-C(38)
2.051(3)
2.056(3)
Ag(1)-N(1)
N(1)-C(37)
2.627(2)
1.115(3)
N(2)-C(38)
1.152(3)
175.4(2)
P(2)-Ag(1)-P(1)
P(1)-Ag(1)-N(1)
152.21(2)
99.50(5)
N(1)-C(37)-Ag(2)
C(37)-Ag(2)-C(38)
178.2(3)
177.1(1)
P(2)-Ag(1)-N(1)
C(37)-N(1)-Ag(1)
95.31(5)
171.1(2)
N(2)-C(38)-Ag(2)
complex 3a‚(CH3OH)2
Ag(1)-Ag(1A)
Ag(1)-P(1A)
2.8949(7)
2.422(1)
Ag(1)-P(2)
Ag(1)-N(1)
2.408(1)
2.452(4)
N(1)-C(25)
Ag(2)-C(26)
1.103(6)
2.029(6)
P(1)-C(27)
P(2)-C(27)
1.827(4)
1.850(4)
Ag(2)-C(25)
N(2)-C(26)
2.060(5)
1.142(7)
P(2)-Ag(1)-P(1A)
155.80(4) P(2)-Ag(1)-N(1)
107.5(1) C(25)-N(1)-Ag(1) 153.8(4) N(1)-Ag(1)-Ag(1A) 89.7(1) P(1)-C(27)-P(2) 113.3(2)
P(2)-Ag(1)-Ag(1A) 92.33(3) C(27)-P(1)-Ag(1A) 108.7(1) N(1)-C(25)-Ag(2) 172.5(5) C(26)-Ag(2)-C(25) 179.9(3)
P(1A)-Ag(1)-Ag(1A) 87.83(3) C(27)-P(2)-Ag(1) 113.3(1) P(1A)-Ag(1)-N(1) 96.8(1) N(2)-C(26)-Ag(2) 178.4(8)
complex 3b
Ag(1)-Ag(1A)
Ag(1)-P(1)
2.9512(9)
2.4087(9)
Ag(1)-P(2A)
Ag(1)-N(1)
2.4125(9)
2.522(2)
N(2)-C(27)
Ag(2)-C(26)
1.145(5)
2.052(3)
P(1)-C(25)
P(2)-C(25)
1.839(3)
1.846(3)
Ag(3)-C(27)
C(26)-N(1)
2.040(5)
1.139(4)
P(1)-Ag(1)-P(2A)
158.95(2) P(1)-Ag(1)-N(1)
102.91(7) C(26)-N(1)-Ag(1) 140.1(2) N(1)-Ag(1)-Ag(1A) 87.71(7)
P(1)-C(25)-P(2) 116.0(1)
P(1)-Ag(1)-Ag(1A) 86.89(2) C(25)-P(1)-Ag(1) 111.71(7) N(1)-C(26)-Ag(2) 174.0(2) C(27)-Ag(3)-C(27A) 180.000(1)
P(2A)-Ag(1)-Ag(1A) 94.24(2) C(25)-P(2)-Ag(1A) 111.58(9) P(2A)-Ag(1)-N(1) 98.14(7) N(2)-C(27)-Ag(3)
178.1(3)
complex 4
Cu(1)-C(55)
Cu(1)-N(3A)
Cu(1)-P(1)
1.876(3)
1.945(4)
2.243(1)
Cu(2)-P(2)
N(2)-C(56)
Cu(3)-N(2)
2.264(1)
1.173(4)
1.950(3)
N(1)-C(55)
Cu(2)-N(1)
Cu(2)-C(56)
1.159(4)
1.950(3)
1.870(4)
Cu(3)-C(57)
Cu(3)-P(3)
N(3)-C(57)
1.866(3)
2.209(1)
1.174(4)
C(55)-Cu(1)-N(3A) 116.4(1) C(56)-Cu(2)-N(1) 125.4(1) C(56)-N(2)-Cu(3) 166.4(3) N(1)-Cu(2)-P(2) 113.14(9) N(1)-C(55)-Cu(1) 174.2(4)
C(55)-Cu(1)-P(1) 117.7(1) N(2)-Cu(3)-P(3) 121.3(1) C(57)-N(3)-Cu(1A) 175.2(3) C(57)-Cu(3)-N(2) 106.9(1) N(2)-C(56)-Cu(2) 172.9(3)
N(3A)-Cu(1)-P(1) 125.66(9) C(55)-N(1)-Cu(2) 170.3(3) C(56)-Cu(2)-P(2) 121.3(1) C(57)-Cu(3)-P(3) 131.7(1) N(3)-C(57)-Cu(3) 169.7(3)
complex 5‚(CH2Cl2)2
Cu(1)-Cu(1*)
Cu(1)-P(2)
2.940(1)
2.262(1)
P(2)-C(2)
P(1)-C(2)
1.844(4)
1.847(3)
Cu(1)-P(1*)
P(1)-Cu(1*)
2.263(1)
2.263(1)
Cu(1)-C(1)
N(1)-C(1)
1.985(4)
1.101(5)
P(2)-Cu(1)-P(1*) 138.76(4) C(1)-Cu(1)-P(2)
114.2(1) N(1)-C(1)-Cu(1) 178.0(4) C(1)-Cu(1)-Cu(1*) 104.9(1) C(2)-P(2)-Cu(1) 111.2(1)
C(1)-Cu(1)-P(1*) 106.9(1) P(1*)-Cu(1)-Cu(1*) 82.58(3) C(2)-P(1)-Cu(1*) 105.3(1) P(2)-Cu(1)-Cu(1*) 90.33(3) P(2)-C(2)-P(1)
113.6(2)
Complex 6(PF6)‚Et2O
Cu(1)-N(1)
N(1)-C(1n)
Cu(2)-C(1n)
2.014(8)
1.15(1)
1.998(8)
Cu(1)-P(3)
P(4)-C(28)
Cu(1)-P(1)
2.412(3)
1.829(8)
2.333(3)
P(1)-C(1)
C(1)-C(2)
Cu(2)-P(4)
1.837(9)
1.56(1)
2.473(3)
P(3)-C(27)
C(27)-C(28)
P(2)-C(2)
1.870(9)
1.55(1)
1.825(9)
Cu(1)-P(2)
2.321(3)
N(1)-Cu(1)-P(3)
95.1(2)
C(27)-P(3)-Cu(1) 108.6(3) P(2)-Cu(1)-P(3)
120.6(1) C(27)-C(28)-P(4) 114.2(6) C(2)-P(2)-Cu(1) 104.7(3)
C(1n)-N(1)-Cu(1) 158.1(7) N(1)-Cu(1)-P(2)
115.2(2) P(2)-Cu(1)-P(1)
88.79(9) C(1)-P(1)-Cu(1)
101.5(3)
110.2(6)
112.8(6)
N(1)-C(1n)-Cu(2) 161.2(7) N(1)-Cu(1)-P(1)
C(1n)-Cu(2)-P(4) 96.4(2)
114.6(2) C(28)-P(4)-Cu(2) 106.6(3) C(2)-C(1)-P(1)
124.5(1) C(28)-C(27)-P(3) 114.3(6) C(1)-C(2)-P(2)
P(1)-Cu(1)-P(3)
complex 7(PF6)‚0.5CH3CN
Cu(1)-N(1)
Cu(1)-P(3)
N(1)-C(1)
Cu(3)-C(1)
1.985(7)
2.308(2)
1.129(8)
1.970(6)
Cu(3)-C(2)
C(31)-C(32)
C(30)-C(31)
P(3)-C(30)
1.964(5)
1.526(8)
1.541(9)
1.834(6)
Cu(1)-P(1)
P(1)-C(3)
N(2)-C(2)
Cu(2)-N(2)
2.285(2)
1.832(7)
1.147(8)
1.972(7)
Cu(2)-P(4)
P(4)-C(32)
C(3)-C(4)
C(4)-C(5)
2.304(2)
P(2)-C(5)
Cu(1)-P(2)
1.847(6)
2.300(2)
1.840(7)
1.54(1)
1.53(1)
N(1)-Cu(1)-P(3) 109.8(2) N(2)-C(2)-Cu(3)
166.1(6) P(1)-Cu(1)-P(2) 98.50(7) C(32)-P(4)-Cu(2) 112.1(2) C(4)-C(5)-P(2)
113.7(5)
C(1)-N(1)-Cu(1) 167.1(6) C(32)-C(31)-C(30) 111.7(5) C(3)-P(1)-Cu(1) 107.7(2) C(31)-C(32)-P(4) 110.4(4) C(5)-P(2)-Cu(1) 113.5(2)
N(1)-C(1)-Cu(3) 165.6(6) C(31)-C(30)-P(3)
C(2)-Cu(3)-C(1) 100.8(2) C(30)-P(3)-Cu(1)
112.3(4) C(2)-N(2)-Cu(2) 166.0(6) C(4)-C(3)-P(1)
114.6(2) N(2)-Cu(2)-P(4) 108.5(2) C(5)-C(4)-C(3)
113.2(5)
114.2(6)
complex 8‚(Et2O)2
Cu(1)-C(1)
N(1)-C(1)
Cu(3)-N(1)
1.918(5)
1.140(5)
1.933(4)
Cu(2)-C(3)
N(3)-C(3)
Cu(3)-N(3*)
1.937(4)
1.148(5)
1.922(5)
Cu(1)-C(2)
N(2)-C(2)
Cu(2)-N(2)
1.931(5)
1.156(5)
1.925(4)
Cu(1)-P(1)
Cu(2)-P(2)
Cu(3)-P(3)
2.264(1)
2.215(1)
2.255(1)
C(1)-Cu(1)-C(2) 128.9(2) N(2)-C(2)-Cu(1)
C(1)-Cu(1)-P(1) 124.2(1) N(3)-C(3)-Cu(2)
176.5(4) N(3*)-Cu(3)-N(1) 124.4(2) N(2)-Cu(2)-C(3) 106.1(2) N(3*)-Cu(3)-P(3) 128.2(1)
162.2(4) N(1)-Cu(3)-P(3)
107.3(1) N(2)-Cu(2)-P(2) 133.4(1) N(1)-C(1)-Cu(1)
170.1(4) C(3)-Cu(2)-P(2) 120.1(1) C(1)-N(1)-Cu(3)
176.7(4)
168.3(4)
C(2)-Cu(1)-P(1) 106.9(1) C(3)-N(3)-Cu(3*) 173.2(4) C(2)-N(2)-Cu(2)
-
- 34
actions33 and in [Ag2(dcpm)2]X2 (X ) CF3SO3 , PF6 )
solids, and the latter were found by spectroscopic means to
exhibit weak Ag-Ag interactions.
The molecular structure of 3b shows virtually the same
[Ag2(µ-dcpm)2]2+ core with chairlike [Ag2P4C2] conformation
(Figure S1 in the Supporting Information) as that observed
Inorganic Chemistry, Vol. 44, No. 5, 2005 1517

Lin et al.
Figure 3. Perspective view of [Ag2(µ-dcpm)2][Ag(CN)2]2‚(CH3OH)2, 3a‚
(CH3OH)2 (30% probability ellipsoids).
2.522(2) Å in 3b is also lengthened. The two [NCAgCN]-
units are approximately perpendicular to the Ag‚‚‚Ag vector.
The crystal structure of 4 consists of infinite one-
dimensional [(Cy3P)Cu(CN)]∞ zigzag chains with cyanide
as a bridging ligand for [Cu(PCy3)]+ moieties (Figure 4).
Similar Cu(CN) chains in the tetrahedral copper(I) diimine
polymer [Cu(dmphen)(CN)]n (dmphen ) 2,9-dimethyl-1,10-
phenanthroline)35 were previously reported. Each copper
atom in 4 adopts a distorted trigonal planar geometry; the
mean C-Cu-N, N-Cu-P, and C-Cu-P angles are 116.2,
120.0, and 123.6°, respectively. The average Cu-P (2.24
Å), Cu-C (1.87 Å), Cu-N (1.95 Å), and C-N (1.17 Å)
distances agree well with those observed in the related
complexes [Cu(CN)(PPh3)2]6 (Cu-C 1.99 Å, Cu-N 2.02 Å,
C-N 1.16 Å)4d and [(CO)5MCNCu(PPh3)3] (M ) Cr, W;
Cu-N 1.998 Å, C-N 1.15 Å).36 The bridging cyanide ligand
exhibits a span length of ∼4.99 Å between [Cu(PCy3)]+
units, and the [Cu-CN-Cu]+ moieties remain close to
linearity.
Figure 1. Perspective view of [(Cy3P)Ag(NCAgCN)]∞, 1 (30% probability
ellipsoids).
The molecular structure of 5 (Figure 5) shows a cationic
[Cu2(µ-dcpm)2]2+ core that is similar to those of [Ag2(µ-
dcpm)2]2+ in 3a‚(CH3OH)2 and 3b (Figure 3 and Figure S1,
respectively). The two Cu(I) centers are bridged by two dcpm
ligands forming a chairlike [Cu2P4C2] core, and each Cu(I)
is further coordinated to a cyanide ligand to afford a
Y-shaped trigonal CuP2C configuration. This structure was
previously observed in [Cu2(µ-dcpm)2(CH3CN)2]X2 and [Cu2-
Figure 2. Perspective view of [(Cy3P)2Ag(NCAgCN)], 2 (30% probability
ellipsoids).
for 3a‚(CH3OH)2. The intramolecular Ag‚‚‚Ag separation in
3b (2.9512(9) Å) is slightly longer than that of 2.8949(7) Å
in 3a‚(CH3OH)2, whereas the Ag-N(NCAgCN) distance of
-
-
(µ-dcpm)2]X2 (X ) ClO4 , PF6 ).14c,37 The two CuCN units
approach linearity with the N(1)-C(1)-Cu(1) angle of
178.0° and are almost perpendicular to the Cu‚‚‚Cu vector
(C(1)-Cu(1)-Cu(1*) 104.9(1)°). The intramolecular Cu‚‚‚Cu
distance of 2.940(1) Å is close to the limit for metal-metal
interactions; it is longer than those of 2.773(1)-2.821(2) Å
(33) (a) Kim, Y.; Seff, K. J. Am. Chem. Soc. 1978, 100, 175-180. (b)
Eastland, G. W.; Mazid, M. A.; Russell, D. R.; Symons, M. C. R. J.
Chem. Soc., Dalton Trans. 1980, 1682-1687. (c) Papasergio, R. I.;
Raston, C. L.; White, A. H. J. Chem. Soc., Chem. Commun. 1984,
612-613. (d) Kappenstein, C.; Ouali, A.; Guerin, M.; Cˇ erna´k, J.;
Chomicˇ, J. Inorg. Chim. Acta 1988, 147, 189-197. (e) Chen, X. M.;
Mak, T. C. W. J. Chem. Soc., Dalton Trans. 1991, 1219-1222. (f)
Quiro´s, M. Acta Crystallogr., Sect. C 1994, 50, 1236-1239. (g) Singh,
K.; Long, J. R.; Stavropoulos, P. J. Am. Chem. Soc. 1997, 119, 2942-
2943. (h) Omary, M. A.; Webb, T. R.; Assefa, Z.; Shankle, G. E.;
Patterson, H. H. Inorg. Chem. 1998, 37, 1380-1386. (i) Villanneau,
R.; Proust, A.; Robert, F.; Gouzerh, P. Chem. Commun. 1998, 1491-
1492. (j) Zank, J.; Schier, A.; Schmidbaur, H. J. Chem. Soc., Dalton
Trans. 1999, 415-420.
(34) Che, C.-M.; Tse, M.-C.; Chan, M. C. W.; Cheung, K.-K.; Phillips, D.
L.; Leung, K.-H. J. Am. Chem. Soc. 2000, 122, 2464-2468.
(35) Morpurgo, G. O.; Dessy, G.; Fares, V. J. Chem. Soc., Dalton Trans.
1984, 785-791.
(36) Darensbourg, D. J.; Yoder, J. C.; Holtcamp, M. W.; Klausmeyer, K.
K.; Reibenspies, J. H. Inorg. Chem. 1996, 35, 4764-4769.
(37) Mao, Z.; Chao, H.-Y.; Hui, Z.; Che, C.-M.; Fu, W.-F.; Cheung, K.-
K.; Zhu, N. Chem.sEur. J. 2003, 9, 2885-2894.
1518 Inorganic Chemistry, Vol. 44, No. 5, 2005

Ag(I) and Cu(I) Complexes with Phosphine and Cyanide Ligands
Figure 4. Perspective view of [{(Cy3P)Cu(CN)}3]∞, 4 (30% probability ellipsoids).
Figure 6. Perspective view of [{Cu(dcpe)}2(CN)(µ-dcpe)]PF6, 6(PF6) (30%
probability ellipsoids). The C atoms were drawn with small circles for
clarity.
separation of 4.915 Å is excessively long for cuprophilic
interaction. The C(1n)-N(1)-Cu(1) (158.1(7)°) and N(1)-
C(1n)-Cu(2) (161.2(7)°) angles are significantly deviated
from linearity. The copper atoms adopt a distorted tetrahedral
coordination with the N-Cu-P and P-Cu-P angles lying
in the range of 88.12(9)-125.6(1)°.
Figure 7 depicts the structure of 7, which contains a
trinuclear Cu(I) core. Each metal vertex comprises a six-
membered [Cu(dppp)]+ ring in a distorted chair configura-
tion. One [Cu(dppp)]+ group is coordinated to two cyanide
ligands, each of which is further bound to another [Cu-
(dppp)]+ unit. The Cu(1)‚‚‚Cu(3) and Cu(2)‚‚‚Cu(3) separa-
tions are 4.98 Å. Two [Cu(dppp)]+ units are bridged by a
dppp ligand, and the Cu(1)‚‚‚Cu(2) distance is 6.83 Å. The
mean C-N-Cu (166.6°) and N-C-Cu (165.9°) angles are
slightly bent. The three copper atoms adopt a tetrahedral
geometry, and the C(1)-Cu(3)-C(2), N(1)-Cu(1)-P(3),
and N(2)-Cu(2)-P(4) angles are 100.8, 109.8, and 108.5°,
respectively, suggesting minimal angle strain inside the 12-
membered Cu3 core.
Figure 5. Perspective view of [Cu2(µ-dcpm)2(CN)2], 5 (30% probability
ellipsoids).
in [Cu2(µ-dcpm)2X2] (X ) I-, Cl-, SCN-).14c,38 This can be
rationalized by the stronger Cu(I)-CN interaction, which
weakens the Cu(I)‚‚‚Cu(I) interaction. The P(1*)-Cu(1)-
P(2) angle (138.76(4)°) is comparable to those of 139.66-
(5)-145.25(5)° in the [Cu2(µ-dcpm)2X2] (X ) I-, Cl-,
SCN-) complexes.14c,38 The relatively large deviations of
P-Cu-P angles from linearity further suggest that the CN-
ligands are engaged in strong interactions with Cu(I),
comparable to that for the related [Cu2(µ-dcpm)2I2] com-
plex.14c,37
As depicted in Figure 6, the two copper atoms in 6 are
each chelated by a dcpe ligand to give five-membered [Cu-
(dcpe)]+ moieties, and these are bridged by one cyanide
linker and a dcpe ligand to afford the eight-membered [Cu-
(CN)(dcpe)Cu]+ ring. The diameter of the core is estimated
to be ∼5 Å, whereas the intramolecular Cu(1)‚‚‚Cu(2)
The structure of [Cu(CN)(PCy3)]6 (8) features a hexagonal-
like 18-membered ring with six three-coordinate copper
(38) Tse, M.-C. Ph.D. Thesis, The University of Hong Kong, 1999.
Inorganic Chemistry, Vol. 44, No. 5, 2005 1519

Lin et al.
Figure 9. UV-vis absorption spectra of 1, 2, and 3a in acetonitrile at
298 K.
Table 3. UV-Visible Absorption Data of Complexes 1-8
Figure 7. Perspective view of [{Cu(dppp)}3(CN)2(µ-dppp)]PF6, 7(PF6)
(30% probability ellipsoids). The C atoms were drawn with small circles
for clarity.
complex
λ
max/nm (ꢀ/dm3 mol-1 cm-1
)
[(Cy3P)Ag(NCAgCN)]∞, 1a
[(Cy3P)2Ag(NCAgCN)], 2a
[Ag2(µ-dcpm)2][Ag(CN)2]2, 3aa
[Ag2(µ-dcpm)2][Ag(CN)2]2, 3ba
[{(Cy3P)Cu(CN)}3]∞, 4b
218 (7200), 245 (350)
203 (31500), 216 (sh, 23000)
258 (17300)
257 (18000)
236 (44000), 246 (sh, 27600),
270 (sh, 4240)
276 (17600)
239 (78000), 280 (sh, 2500),
349 (560)
272 (57800)
247 (sh, 40400), 282 (sh, 2930)
[Cu2(µ-dcpm)2(CN)2], 5b
[{Cu(dcpe)}2(CN)(µ-dcpe)]PF6, 6(PF6)b
[{Cu(dppp)}3(CN)2(µ-dppp)]PF6, 7(PF6)b
[Cu(CN)(PCy3)]6, 8b
a In acetonitrile. b In dichloromethane.
Electronic Absorption Spectroscopy. The UV-visible
spectra of 1 and 2 in acetonitrile are depicted in Figure 9,
and the spectral data are listed in Table 3. For 1, a strong
absorption band at 218 nm (ꢀ ) 7200 dm3 mol-1 cm-1) and
a weak shoulder at 245 nm (ꢀ ) 350 dm3 mol-1 cm-1) are
observed. An intense high-energy absorption band at λmax
) 203 nm with a shoulder at 216 nm (ꢀ ) 31 500 and 23 000
dm3 mol-1 cm-1, respectively) has also been observed for
2. The profiles of the absorption spectra for 1 and 2 are
similar to that of a dilute aqueous solution of K[Ag(CN)2]
(5.0 × 10-4 mol dm-3) as reported by Patterson and co-
workers.15 For the µ-dcpm bridged complexes 3a and 3b,
intense absorption bands at λmax ) 258 (ꢀ ) 17 300 dm3
mol-1 cm-1) and 257 nm (ꢀ ) 18 000 dm3 mol-1 cm-1),
respectively, are observed in CH3CN, and they are compa-
rable to the 1[4dσ* f 5pσ] transition at 266 nm (ꢀ ) 22 000
dm3 mol-1 cm-1) previously reported for the [Ag2(dcpm)2]2+
salts.34
Figure 10 depicts the absorption spectra of 4, 5, 6, and 8
in dichloromethane at 298 K. The absorption spectrum of 4
exhibits a peak at λmax ) 236 nm (ꢀ ) 44 000 dm3 mol-1
cm-1) with weak and broad absorption tailing from 270 to
350 nm (ꢀ ) 4240-920 dm3 mol-1 cm-1). The absorption
spectrum of 5 exhibits an intense absorption at λmax ) 276
nm, the ꢀ value of which (17 600 dm3 mol-1 cm-1) is
significantly higher than that of 4 at 270 nm (4240
dm3mol-1cm-1). Our previous work on [Cu2(dmpm)3]2+
shows that the [3dσ* f 4pσ] transition of this compound
Figure 8. Perspective view of [Cu(CN)(PCy3)]6, 8 (30% probability
ellipsoids).
vertexes in approximately trigonal planar geometry and
bridged by six cyanide linkages (Figure 8). The structure is
reminiscent of [Cu(CN)(PPh3)2]6,4d except that each copper
atom is coordinated to one PCy3 ligand instead of two PPh3
ligands in [Cu(CN)(PPh3)2]6. The six cyanide linkers between
the [Cu(PCy3)]+ vertexes constitute six sides of the hexagonal-
like core, and the mean Cu‚‚‚Cu separation is ∼5 Å. The
C-N-Cu and N-C-Cu angles (162.2-176.7°) slightly
deviate from 180°, and indeed, the hexagonal core is
nonplanar. The N(2)-Cu(2)-C(3) (106.1(2)°) angle shows
a significant deviation from the 120° value expected for a
hexagonal-shaped macrocycle, while the other C/N-Cu-
C/N angles are ∼124.4°. The distances between opposing
copper atoms are 8.90, 11.50, and 8.68 Å. The dimensions
of the central core are estimated to be 11.5 Å in length and
7.3 Å in width.
1520 Inorganic Chemistry, Vol. 44, No. 5, 2005

Ag(I) and Cu(I) Complexes with Phosphine and Cyanide Ligands
Figure 11. Room-temperature solid-state emission of 1, 2, 4, and 6 (λex
) 250 nm).
Figure 10. UV-vis absorption spectra of 4, 5, 6, and 8 in dichloromethane
λmax ) 360 nm with a lifetime of ∼45 µs. An additional
peak at 412 nm was also found in the spectrum of 3a. The
emission lifetimes of 1-3a,b recorded in 77 K glassy
solutions are significantly longer compared to those recorded
in acetonitrile at 298 K, revealing a large temperature
dependence of the emission lifetimes. The room-temperature
solid-state emission spectra of 1-3a,b exhibit peaks at λmax
) 356-408 nm (Figure 11). At 77 K, the solid-state emission
of 1 occurs at λmax ) 366 nm, whereas those of 2-3a,b are
at 347-382 nm. The emission quantum yields and lifetimes
of solid samples of 1-3a,b measured at 298 K are (2.3-
8.0) × 10-3 and 0.6-87 µs, respectively.
at 298 K.
occurs at λmax ) 276 nm (ꢀ ) 10 800 dm3 mol-1 cm-1) in
H2O,37 which is similar to the 276-nm band of 5. The
absorption spectrum of 6 shows an intense band at λmax
)
239 nm (ꢀ ) 78 000 dm3mol-1cm-1) and a weak shoulder
at 280 nm (ꢀ ) 2500 dm3 mol-1 cm-1), whereas that of 8
exhibits a weak absorption tail from 282 to 326 nm (ꢀ )
2930-370 dm3 mol-1 cm-1). Such weak absorption in the
265-350-nm spectral region for 8 is comparable to that
observed for 4 and is consistent with the absence of close
intramolecular metal-metal interactions. For 7, the 272-nm
absorption band with a large ꢀ value of 57 800 dm3 mol-1
cm-1 is slightly red-shifted from the 252-nm absorption (ꢀ
) 15 000 dm3 mol-1 cm-1) of the free dppp ligand, which
can be assigned to be mainly contributed by intraligand
transition of the dppp ligand.
Complexes 4-6 and 8 are nonemissive in CH2Cl2 or CH3-
CN, whereas 7 is weakly emissive with λmax ) 445 nm in
dichloromethane at 298 K. In MeOH/EtOH (1:4) glass at
77 K, 4-8 display intense emission at λmax ) 382-416 nm.
A weak, broad emission with λmax ) 500 and 549 nm was
recorded for MeOH/EtOH glassy solutions of 5 and 6,
respectively. These visible emissions are comparable in
energy with that of [Cu(dcpm)2](PF6)2 (λmax ) 506 nm) and
[Cu2(dmpm)3](ClO4)2 (λmax ) 521 nm) recorded under similar
Solution- and Solid-State Emission Spectroscopy. Emis-
sion data for 1-8 are listed in Table 4. Complexes 1 and 2
are nonemissive at 298 K in CH3CN, whereas 3a and 3b
show weak luminescence at λmax ) 365 nm in CH3CN at
298 K with a quantum yield of ∼6 × 10-3 and lifetime of
∼0.2 µs. In MeOH/EtOH (1:4) glass at 77 K, 1 and 2 exhibit
an intense emission at λmax ) 397 and 391 nm with lifetime
of 268 and 320 µs, respectively. The excitation spectrum of
1 (concentration ) 1.0 × 10-3 M) in glassy MeOH/EtOH
(1:4) solution exhibits a peak at 238 nm, which is similar to
the 250-nm excitation band for the 390-nm emission of
K[Ag(CN)2] in frozen (77 K) aqueous solution at the same
complex concentration.15 A 77 K MeOH/EtOH (1:4) glassy
solution of 3a or 3b shows an intense, broad emission at
37
3
2
2
conditions and are attributed to originate from the [(3dx -y
,
dxy)1(4pz)1] excited state of a Cu(I) site. Complex 4 exhibits
an intense solid-state emission at λmax ) 401 (φo ) 2.0 ×
10-3) and 405 nm at 298 (Figure 11) and 77 K, respectively,
and there is a significant temperature dependence of the
emission lifetime [τ ) 1.0 µs at 298 K to 109 µs at 77 K].
The solid-state emission of 5 with λmax at 470 nm (298 K)
and 488 nm (77 K) are red-shifted from those observed for
4 (401 nm at 298 K; 405 nm at 77 K), but they are
comparable to the solid-state emission of [Cu2(dcpm)2]X2
Table 4. Emission Data of Complexes 1-8 (λex ) 250 nm)
solid state
fluid (concentration 5 × 10-4 M)
298 K
77 K
298 K
77 Kc
λmax/nm; φo; τo/µs
λ
max/nm (τo/µs)
λ
max/nm; φo; τo/µs
λ
max/nm (τo/µs)
[(Cy3P)Ag(NCAgCN)]∞, 1
[(Cy3P)2Ag(NCAgCN)], 2
356; 8.0 × 10-3; 5.4
366 (50)
347 (58)
381 (55)
382 (58)
405 (109)
488 (123)
408 (204)
462 (430)
410 (86)
nonemissivea
397 (268)
391 (320)
360 (max, 48), 412 (535)
360 (43)
400 (130)
360; 6.5 × 10-3; 0.6
nonemissivea
[Ag2(µ-dcpm)2][Ag(CN)2]2‚(CH3OH)2, 3a‚(CH3OH)2 408; 2.3 × 10-3; 87
365; 6.1 × 10-3; 0.26a
365; 6.7 × 10-3; 0.20a
nonemissiveb
[Ag2(µ-dcpm)2][Ag(CN)2]2, 3b
[{(Cy3P)Cu(CN)}3]∞, 4
[Cu2(µ-dcpm)2(CN)2], 5
[{Cu(dcpe)}2(CN)(µ-dcpe)]PF6, 6(PF6)
[{Cu(dppp)}3(CN)2(µ-dppp)]PF6, 7(PF6)
[Cu(CN)(PCy3)]6, 8
395; 3.7 × 10-3; 31
401; 2.0 × 10-3; 1.0
470; 8.0 × 10-2; 28
422; 4.9 × 10-3; 4.8
462; 6.8 × 10-3; 3.7
415; 3.0 × 10-3; 2.0
nonemissiveb
382 (max, 60), 500 (sh, 341)
416 (max, 320), 549 (298)
nonemissiveb
445; 1.76 × 10-3; 0.30b 405 (1370)
nonemissiveb
405 (96)
a In CH3CN. b In CH2Cl2. c In EtOH/MeOH (4:1).
Inorganic Chemistry, Vol. 44, No. 5, 2005 1521

Lin et al.
and this can afford compounds with diverse structures and
dimensionalities. Reaction of PCy3 with AgCN afforded the
polymer [(Cy3P)Ag(NCAgCN)]∞ (1), bearing AgCN to PCy3
in a 2:1 ratio. The structure of 1 is similar to that described
for the four-coordinate pyridine-solvated silver(I) polymer
[{(o-tolyl)3P}Ag(py)(NCAgCN)]∞.7 The {Ag(CN)}∞ back-
bone in 1 resembles that of the CuCN chain in [Cu4(CN)4-
(2,2′-biquinoline)]∞.42 However, in solution such as dichlo-
romethane, the polymeric solid 1 is likely present as
monomers or oligomers. The structure and stoichiometry of
2 are comparable to the repeating unit in the [(Ph3P)2Ag-
(NCAgCN)]∞ polymer.7 The structures of 1 and 4 are similar;
both have a zigzag polymeric configuration with a three-
coordinate metal center coordinated by two cyanide groups
and one PCy3 unit. The difference is that the [(Cy3P)Ag]+
units in 1 are bridged by [NCAgCN]-, whereas the [(Cy3P)-
Cu]+ groups in 4 are linked by a CN- ligand. As for 1, it is
unlikely that solid 4 retains its polymeric structure. Com-
plexes 3a and 3b with close intramolecular Ag‚‚‚Ag distances
could be viewed as models for weakly interacting AgCN
units, and they show structural resemblance to the [Ag2-
(dcpm)2]X2 complexes, the UV-visible absorption spectra
of which show distinct [4dσ* f 5pσ] transition.34 The
molecular structures of 5-8 reveal negligible Cu‚‚‚Cu
contacts, although the CuI‚‚‚CN- interaction in 5 should not
be overlooked in photophysical assignment (see below).
Figure 12. Room-temperature solid-state emission of 8 (λex ) 250 and
350 nm).
-
-
(X ) ClO4 , PF6 , I-) with emission maxima at 460-475
nm at 298 K, respectively.37 When solid samples of 6 and 8
(Figures 11, 12) are excited at 250 nm, a broad structureless
emission at 408-422 nm appears, which is similar in energy
to that observed for 4 (Figure 11). Upon excitation of a
crystalline sample of 8 at 350 nm, a broad emission with
λ
max at 510 nm (Figure 12) and 506 nm was observed at 298
and 77 K, respectively. The change in solid-state emission
energy of 8 with the excitation energy indicates that the
emissions may originate from multiple sites. The solid-state
emission of 7 (λmax ) 462 nm) at 298 K is red-shifted from
the 423-nm emission of the solid dppp. We assign the former
3
2
2
to come from a [(3dx -y , 3dxy)(4pz)] excited state of a three-
coordinate Cu(I) site, although mixing with an intraligand
triplet excited state of dppp could not be excluded. The solid-
state emission quantum yields of 4 and 6-8 lie between 2.0
× 10-3 and 6.8 × 10-3, whereas that of 5 exhibits a
comparatively higher quantum yield of 8.0 × 10-2.
Solutions of 3a and 8 in CH3OH and CH2Cl2, respectively,
were used for preparation of thin films supported on glass
slides to investigate the response to organic vapors.39
Methanol, chloroform, acetone, acetonitrile, and ethanol
vapors were produced by the diffusion tube method.40 The
N2 gas containing the organic vapor was fed into a flow cell
in which the film was exposed to the gas stream, and the
glass slide was oriented to face the excitation light source
in the luminescence spectrometer (Perkin-Elmer LS-50B).
However, no emission response toward these volatile organic
compounds was detected.
Absorption Energies. The high-energy intense absorption
bands at λ ) 203-218 nm (ꢀ ) (7.2 × 103)-(3.2 × 104)
dm3 mol-1 cm-1) for 1 and 2 are assigned to strongly allowed
charge-transfer transitions, and similar transitions have been
noted for the [Ag(CN)2]- salts by Mason.43 In the absorption
spectrum of 1, the lowest-energy band at λmax ) 245 nm
with an extinction coefficient of 350 dm3 mol-1 cm-1
signifies a forbidden transition (Figure 9). The intense
absorption band of the µ-dcpm bridged complexes 3a and
3b in CH3CN solution with λmax at ∼257 nm (ꢀ ≈ 1.8 × 104
dm3 mol-1 cm-1) is in contrast with the absorption spectra
of the mononuclear derivatives [(Cy3P)Ag(O2CCF3)] and
[Ag(PR3)2]ClO4 (R ) Me, Cy), while the latter show ꢀ values
below 102 at λ g 250 nm. The high ꢀ values for the 257-nm
absorption band of 3a and 3b are comparable to those for
the [4dσ* f 5pσ] transition observed at λmax ) 266 nm (ꢀ
) 22000 dm3 mol-1 cm-1) for the related [Ag2(µ-dcpm)2]-
X2 (X ) CF3SO3 and PF6 ),34 the spectroscopic assignment
of which was supported by resonance Raman experiments.
Therefore, the absorption bands of 3a and 3b at λmax ≈ 257
-
-
Discussion
General Remarks. As described for the copper(I) cyano-
diimine system,41 subtle changes in reaction conditions can
lead to profound variations in products. In this work,
reactions were undertaken in different stoichiometric ratios
of the reactants, giving compounds with various coordination
modes, geometries, and component stoichiometries. The
[Ag(CN)2]- moiety can act as an isolated counterion, a
terminal ligand via one cyano group, or a bridging spacer,
1
nm are assigned to the [4dσ* f 5pσ] transition.
The high-energy absorptions of 4 at λ < 250 nm show
substantial extinction coefficients of (2.8-4.4) × 104 dm3
mol-1 cm-1, which are comparable to that observed for
[Cu(CN)2]-,44 and these are assigned to charge-transfer
absorptions. The less intense absorption shoulder tailing from
270 (ꢀ ) 4240 dm3 mol-1 cm-1) to 300 nm (ꢀ ) 1360 dm3
(39) Lu, W.; Chan, M. C. W.; Zhu, N.; Che, C.-M.; He, Z.; Wong, K.-Y.
Chem.sEur. J. 2003, 9, 6155-6166.
(40) Altshuller, A. P.; Cohen, I. R. Anal. Chem. 1960, 32, 802-810.
(41) (a) Chesnut, D. J.; Kusnetzow, A.; Birge, R.; Zubieta, J. Inorg. Chem.
1999, 38, 5484-5494. (b) Chesnut, D. J.; Plewak, D.; Zubieta, J. J.
Chem. Soc., Dalton Trans. 2001, 2567-2580.
(42) Chesnut, D. J.; Zubieta, J. Chem. Commun. 1998, 1707-1708.
(43) (a) Mason, W. R. J. Am. Chem. Soc. 1973, 95, 3573-3581. (b) Mason,
W. R. J. Am. Chem. Soc. 1976, 98, 5182-5187.
(44) Horva´th, A.; Zsila´k, Z.; Papp, S. J. Photochem. Photobiol., A 1989,
50, 129-139.
1522 Inorganic Chemistry, Vol. 44, No. 5, 2005

Ag(I) and Cu(I) Complexes with Phosphine and Cyanide Ligands
mol-1 cm-1) is tentatively assigned to metal-centered [3d
f (4p, 4s)] transition (Figure 10). For 5, the intense
absorption band with λmax at 276 nm and ꢀ value of 17 600
dm3 mol-1 cm-1 resembles the metal-metal-bonded 1[3dσ*
f 4pσ] transitions of [Cu2(dmpm)3]2+ at λmax ) 276 nm (ꢀ
) 10 800 dm3 mol-1 cm-1) in H2O37 and [Cu2(dcpm)2]X2
) 491 nm, an assignment of Cu-Cu-bonded excited state
for the solid-state emission of 5 is precluded. We suggest
that the interaction between the [Cu2(dcpm)2]2+ core and CN-
could stabilize the excited state, which could lead to a lower-
3
2
2
energy [(3dx -y , 3dxy), 4pz] excited state. Coordination of a
halide ion to the excited *[Cu(CN)2]- moiety in aqueous
solution upon UV irradiation was previously observed to
afford a highly luminescent exciplex with an emission band
at 480 nm.17a,44,45 This is similar in energy to the 470-nm
emission of the [Cu2(dcpm)2(CN)2] solid (5). The solid-state
emission of 8 at 298 and 77 K is dependent on the excitation
wavelength; a red-shift of the emission maximum at 298 K
was observed from 415 to 510 nm as the excitation
wavelength increased from 250 to 350 nm. We propose that
the six Cu(I) sites exhibit subtly different coordination
environments within the hexagonal-like geometry of 8 in the
solid state, and these environments respond to different
excitation wavelengths and emit at slightly varying energies.46
-
- 14c
(X ) ClO4 , PF6 ) at λmax ) 307-311 nm (ꢀ ≈ 15 000
dm3 mol-1 cm-1) in CH2Cl2. Thus, we similarly assign this
1
absorption to a [3dσ* f 4pσ] transition (or 3d f (4p, 4s)
modified by Cu(I)-Cu(I) interaction). Complex 5 can be
regarded as two weakly interacting CuCN units via Cu‚‚‚
Cu contacts. The absorption spectra of 6 and 8 do not reveal
a distinct absorption peak at λ > 270 nm that could be
assigned to the [3dσ* f 4pσ] transition. Rather, these two
complexes show a broad absorption tailing from λ ) 270
nm (ꢀ ) 3390-4320 dm3 mol-1 cm-1) to 300-325 nm (ꢀ
≈ 300-390 dm3 mol-1 cm-1, which are similar to that of 4
at 270 nm (ꢀ ) 4240 dm3 mol-1 cm-1). This is consistent
with the structural data that the copper atoms in 6 and 8 are
noninteracting (Figure 10).
3
2
2
This is in accordance with a [(3dx -y , 3dxy), 4pz] emissive
excited-state assignment.
-
In the literature, oligomerizations of Ag(CN)2 and
Emission Energies. The near-UV solid-state luminescence
of 1 and 2 at λmax ) 356-360 nm are assigned to originate
from a metal-centered triplet excited state of a three-
coordinate silver(I) site, and a tentative assignment would
-
Au(CN)2 ions in solution at high complex concentrations
have been proposed, and these oligomerizations were mani-
fested by red-shifted absorption and emission bands com-
pared to monomer counterparts recorded in low-complex
concentrations.15 While the phenomenon of metal-metal-
bonded exciplex formation could be invoked to rationalize
the spectral data previously observed by Patterson and
Fackler,15,16 this may not be the only factor affecting the
3
2
2
be the [(4dx -y , 4dxy), 5pz] excited state. For the binuclear
complexes 3a and 3b, their solid-state emissions are slightly
red-shifted from that observed for 1 and 2 and can be
attributed to the formation of metal-metal-bonded exci-
plexes. Metal-metal-bonded exciplex formation has previ-
ously been proposed to account for the emission from
-
photoluminescence of M(CN)2 solids. The similarity in
-
energy between the emission of the three-coordinate com-
*[Ag(CN)2 ]n oligomeric sites in the doped crystals of
dicyanoargentates(I).16 For example, [Ag(CN)2]- ions in a
KCl host lattice at 77 K exhibit emission bands over the
λmax ) 295-548-nm range upon excitation at different
wavelengths (λex ) 226-315 nm). This was attributed to
mono-, di-, tri-, and polymeric Ag(I) sites that emit at
different wavelengths because of silver-silver-bonding
interactions in both the ground and excited states. However,
it should be noted that the Stokes’ shifts (∆ν) of the 298-K
solid-state emission for 3a (14 250 cm-1) and 3b (13 600
cm-1) from their respective 1(4dσ* f 5pσ) absorption bands
at ∼258 nm in CH3CN are larger than that reported for the
related binuclear [Au2(dcpm)2]2+ compound (8930 cm-1).14b
Thus, the origin of the emission from the 3a and 3b solids
remains unclear. The small difference between the emission
energies of 1 and 2 with those of 3a and 3b suggests that
the impact of Ag(I)-Ag(I) interaction upon the emission of
3a and 3b is less important than previously envisaged.34 The
lifetimes in the microsecond range are consistent with the
plexes 1 and 2 and some of the high-energy emissions (λmax
) 327-345 nm) for the [Ag(CN)2 ]n solid reported in the
-
literature16a suggests that silver(I)-ligand coordination is
crucial in affecting the emission energy. It is pertinent to
note that monomeric three-coordinate Ag(I) and Cu(I) species
bearing CN- ancillary ligands exhibit near-UV photolumi-
nescence at ∼360 and 400 nm, respectively, and the high-
emission energy is consistent with the large nd - [(n + 1)(s,
p)] band gap of Cu(I) and Ag(I).
It is interesting to note that the photoluminescence from
these Ag(I)- and Cu(I)-cyanide solids can be intense and
have long lifetimes. These photophysical features signify the
potential applications of Ag(I)- and Cu(I)-CN solids as
new classes of blue light-emitting materials. Although Ag-
(I)-Ag(I) and Cu(I)-Cu(I) interactions could modify the
metal-centered [nd f (n + 1)(p, s)] transition energy, the
effect of Ag(I)-Ag(I) interaction upon the photoluminescent
energy can be latent, as revealed by the comparable emission
energies of 1 and 2 relative to those of 3a and 3b.
3
2
2
triplet excited-state assignment. The [(4dx -y , 4dxy), 5pz]
excited state appears to play an important role in affecting
the photoluminescence of these Ag(I) solids.
Concluding Remarks
The employment of a sterically unencumbered [Ag(CN)2]-
building block has yielded, depending on the initial reactant
The 77 K glassy solution of 4-8 exhibit intense lumi-
nescence at λmax ) 382-416 nm. The solid-state emission
of 5 [λmax ) 470 (298 K) and 488 nm (77 K)] is significantly
red-shifted in energy from that observed for 4 [λmax ) 401
(298 K) and 405 nm (77 K)]. Referring to the room-
temperature solid-state emission of [Cu(PCy3)2]ClO4 at λmax
(45) (a) Horva´th, A.; Papp, S.; De´csy, Z. J. Photochem. 1984, 24, 331-
339. (b) Horva´th, A.; Stevenson, K. L. Inorg. Chim. Acta 1991, 186,
61-66.
(46) Henary, M.; Zink, J. I. Inorg. Chem. 1991, 30, 3111-3112.
Inorganic Chemistry, Vol. 44, No. 5, 2005 1523

Lin et al.
stoichiometry, a one-dimensional chain with alternate [(Cy3P)-
Ag]+ and [Ag(CN)2]- units or a discrete [(Cy3P)2Ag-
(NCAgCN)] molecule. Reactions of MCN (M ) Ag(I),
Cu(I)), or [Cu(CH3CN)4]PF6 (with KCN) with bidentate
R2P-(CH2)n-PR2 (R ) Cy, n ) 1-2; R ) Ph, n ) 3)
phosphine ligands afforded a series of bi- and trinuclear
macrocycles. Both metal-metal interaction and metal-
ligand coordination have been observed to affect the pho-
tophysical properties of these M(I)-CN solids. The existence
of M(I)-M(I) interaction in the excited state has been
verified by the presence of an intense dipole-allowed, red-
shifted absorption attributed to the [ndσ* f (n + 1)pσ]
transition, but the 3[(n + 1)pσ, ndσ*] emission could not be
assigned without ambiguity. The metal-ligand coordination
in both ground and excited states leads to emission from the
metal-bonded excited state of Ag(I) and Cu(I) metal-cyanide
complexes should be cautious, and metal-anion coordination
at two-coordinate d10 metal site should be taken into
consideration in the spectroscopic assignments of these
systems.
Acknowledgment. We are grateful for financial support
from The University of Hong Kong, HKU Large Item
Equipment Grant, Research Grants Council of the Hong
Kong SAR, China (HKU 7039/03P), and the National
Natural Science Foundation of China/Research Grants Coun-
cil Joint Research Scheme (N_HKU 742/04). We thank Dr.
Kong-Hung Sze for helpful discussions on NMR spectros-
copy.
Supporting Information Available: Listings of crystal data,
atomic coordinates, calculated coordinates, anisotropic displacement
parameters, and bond lengths and angles for 1-8 in CIF format;
31P{1H} NMR spectra of 7 in CDCl3 at different temperature and
31P-31P COSY spectrum of 7 in CD2Cl2 at 25 °C. This material is
available free of charge via the Internet at http://pub.acs.org.
3
2
2
[(ndx -y , ndxy), (n + 1)pz] state of a three-coordinate M(I)
site. Interestingly, such emissions are found at comparable
3
or lower energy than the expected [(n + 1)pσ, ndσ*]
emission of dinuclear Ag(I)- and Cu(I)-phosphine com-
plexes, the latter would occur at energies in the UV region
(λ < 400 nm). Thus, assignment of emission to a metal-
IC048876K
1524 Inorganic Chemistry, Vol. 44, No. 5, 2005