Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270102013240/gg1124sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270102013240/gg1124Isup2.hkl |
CCDC reference: 197313
The preparation of (I) was carried out as follows. A blue solution containing [Cu(dien)2]2+(aq) cations, formed by mixing a 0.1 M solution of copper nitrate (10 ml, 1 mmol) and dien (0.22 ml, 2 mmol), was mixed with a colourless solution of K[Ag(CN)2], formed by dissolving AgNO3 (0.34 g, 2 mmol) in a 0.4 M solution of KCN (10 ml, 4 mmol). The resultant blue solution was left for crystallization. Blue single crystals of (I) suitable for X-ray analysis were obtained after 1–2 d; these were filtered off and dried in air. Analysis calculated for C17H26Ag5Cu2N15 (Mr 1106.93): C 18.45, H 2.35, N 18.98, Cu 11.48, Ag 48.72%; found: C 18.72, H 2.42, N 19.42, Cu 11.42, Ag 49.20. An IR spectrum (KBr disc) was measured on a Nicolet 510 F T—IR spectrometer from 4000 to 400 cm-1 with absorption bands (cm-1) at 3309 (versus), 3268 (versus), 3238 (versus), 3157 (s), 2165 (s), 2156 (versus), 2133 (s), 2118 (s), 1606 (s), 1598 (s), 1467 (m), 1457 (m), 1429 (m), 1257 (m), 1141 (s), 1086 (versus), 1057 (m), 1021 (versus), 946 (s), 835 (m), 710 (m), 645 (m), 533 (s) and 442 (versus). The electronic spectrum was measured by reflectance using a Specord M40 Instrument (Zeiss Jena) from 30000 to 11000 cm-1 (BaSO4 standard).
The CN site was refined as a 50:50 mixture of both C and N atoms. The Ag3···CN32 distance is 2.082 (3) Å and the CN32—CN32 distance is 1.141 (7) Å, similar for normal CN bond lengths. The H-atom positions were refined with common isotropic displacement parameters for the NH2 and CH2 groups, respectively. There is a short contact between N2—H2 and a symmetry-related Ag3 atom, such that H2···Ag3 2.73 (4) Å.
Data collection: EXPOSE in IPDS (Stoe & Cie, 1999); cell refinement: CELL in IPDS; data reduction: INTEGRATE in IPDS; program(s) used to solve structure: SHELXS86 (Sheldrick, 1985); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 1999).
[Cu(C4H13N3)Ag(CN)2]2[Ag(CN)2][Ag2(CN)3] | F(000) = 1052 |
Mr = 1106.96 | Dx = 2.362 Mg m−3 Dm = 2.36 (1) Mg m−3 Dm measured by flotation |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 8000 reflections |
a = 12.5588 (12) Å | θ = 2.8–30.3° |
b = 17.8070 (12) Å | µ = 4.45 mm−1 |
c = 6.9608 (6) Å | T = 293 K |
β = 90.794 (11)° | Parallelepiped, blue |
V = 1556.5 (2) Å3 | 0.33 × 0.15 × 0.05 mm |
Z = 2 |
Stoe IPDS diffractometer | 4462 independent reflections |
Radiation source: fine-focus sealed tube | 2988 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.056 |
ϕ scans | θmax = 30.3°, θmin = 2.8° |
Absorption correction: numerical (SHELXTL; Sheldrick, 1995) | h = −17→17 |
Tmin = 0.414, Tmax = 0.809 | k = −25→25 |
18169 measured reflections | l = −8→9 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.031 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.067 | All H-atom parameters refined |
S = 0.88 | w = 1/[σ2(Fo2) + (0.0352P)2] where P = (Fo2 + 2Fc2)/3 |
4462 reflections | (Δ/σ)max < 0.001 |
219 parameters | Δρmax = 0.83 e Å−3 |
0 restraints | Δρmin = −0.65 e Å−3 |
[Cu(C4H13N3)Ag(CN)2]2[Ag(CN)2][Ag2(CN)3] | V = 1556.5 (2) Å3 |
Mr = 1106.96 | Z = 2 |
Monoclinic, P21/n | Mo Kα radiation |
a = 12.5588 (12) Å | µ = 4.45 mm−1 |
b = 17.8070 (12) Å | T = 293 K |
c = 6.9608 (6) Å | 0.33 × 0.15 × 0.05 mm |
β = 90.794 (11)° |
Stoe IPDS diffractometer | 4462 independent reflections |
Absorption correction: numerical (SHELXTL; Sheldrick, 1995) | 2988 reflections with I > 2σ(I) |
Tmin = 0.414, Tmax = 0.809 | Rint = 0.056 |
18169 measured reflections |
R[F2 > 2σ(F2)] = 0.031 | 0 restraints |
wR(F2) = 0.067 | All H-atom parameters refined |
S = 0.88 | Δρmax = 0.83 e Å−3 |
4462 reflections | Δρmin = −0.65 e Å−3 |
219 parameters |
Experimental. D=50 mm, Φ 0–200°, ΔΦ 1.0°, 1 min/rec |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
Ag1 | 0.21171 (3) | 0.419404 (15) | 0.19494 (5) | 0.03281 (8) | |
Ag2 | 0.0000 | 0.5000 | 0.0000 | 0.03470 (11) | |
Ag3 | 0.17822 (2) | 0.440834 (16) | 0.64119 (5) | 0.03363 (8) | |
Cu | 0.19075 (3) | 0.18433 (2) | 0.61891 (6) | 0.02184 (10) | |
N1 | 0.0331 (3) | 0.17241 (19) | 0.6590 (5) | 0.0296 (7) | |
H1A | 0.012 (4) | 0.218 (3) | 0.690 (7) | 0.034 (5)* | |
H1B | −0.003 (4) | 0.160 (2) | 0.559 (7) | 0.034 (5)* | |
N2 | 0.2048 (3) | 0.12959 (19) | 0.8741 (5) | 0.0321 (7) | |
H2 | 0.232 (4) | 0.080 (2) | 0.839 (6) | 0.034 (5)* | |
N3 | 0.3431 (3) | 0.21506 (18) | 0.6773 (5) | 0.0285 (7) | |
H3A | 0.379 (4) | 0.208 (2) | 0.572 (7) | 0.034 (5)* | |
H3B | 0.341 (4) | 0.261 (3) | 0.704 (7) | 0.034 (5)* | |
N11 | 0.1780 (3) | 0.26263 (16) | 0.4163 (5) | 0.0282 (7) | |
N12 | 0.2231 (3) | 0.08427 (17) | 0.4517 (5) | 0.0303 (7) | |
N21 | −0.0163 (3) | 0.6725 (2) | 0.1352 (6) | 0.0439 (9) | |
N31 | 0.4001 (3) | 0.3815 (2) | 0.8151 (6) | 0.0444 (9) | |
C32 | 0.0398 (3) | 0.48861 (19) | 0.5275 (5) | 0.0329 (8) | 0.50 |
N32 | 0.0398 (3) | 0.48861 (19) | 0.5275 (5) | 0.0329 (8) | 0.50 |
C11 | 0.1877 (3) | 0.31622 (19) | 0.3255 (6) | 0.0287 (8) | |
C12 | 0.2544 (3) | 0.52626 (19) | 0.1053 (6) | 0.0271 (8) | |
C21 | −0.0148 (3) | 0.6121 (2) | 0.0803 (6) | 0.0338 (9) | |
C31 | 0.3236 (3) | 0.4062 (2) | 0.7514 (6) | 0.0315 (9) | |
C1 | 0.0155 (4) | 0.1164 (3) | 0.8136 (7) | 0.0400 (10) | |
H1C | 0.019 (4) | 0.068 (3) | 0.754 (7) | 0.049 (5)* | |
H1D | −0.041 (4) | 0.123 (3) | 0.870 (8) | 0.049 (5)* | |
C2 | 0.0994 (4) | 0.1303 (3) | 0.9690 (7) | 0.0453 (12) | |
H2A | 0.093 (4) | 0.186 (3) | 1.022 (7) | 0.049 (5)* | |
H2B | 0.100 (4) | 0.098 (3) | 1.043 (8) | 0.049 (5)* | |
C3 | 0.2951 (4) | 0.1616 (3) | 0.9827 (7) | 0.0418 (10) | |
H3C | 0.309 (4) | 0.127 (3) | 1.081 (8) | 0.049 (5)* | |
H3D | 0.268 (4) | 0.208 (3) | 1.019 (7) | 0.049 (5)* | |
C4 | 0.3840 (3) | 0.1728 (3) | 0.8441 (7) | 0.0387 (10) | |
H4A | 0.432 (4) | 0.204 (3) | 0.912 (8) | 0.049 (5)* | |
H4B | 0.410 (4) | 0.121 (3) | 0.795 (7) | 0.049 (5)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Ag1 | 0.04474 (18) | 0.02123 (12) | 0.03246 (19) | −0.00092 (11) | 0.00121 (12) | 0.00723 (11) |
Ag2 | 0.0415 (2) | 0.0328 (2) | 0.0298 (3) | −0.00204 (17) | 0.00086 (18) | 0.00180 (16) |
Ag3 | 0.03189 (16) | 0.03372 (14) | 0.0351 (2) | 0.00696 (11) | −0.00694 (12) | −0.00175 (12) |
Cu | 0.0265 (2) | 0.02080 (18) | 0.0182 (2) | 0.00041 (15) | −0.00066 (16) | 0.00275 (15) |
N1 | 0.0297 (17) | 0.0350 (17) | 0.024 (2) | 0.0026 (13) | −0.0061 (13) | −0.0005 (13) |
N2 | 0.0332 (18) | 0.0361 (17) | 0.027 (2) | 0.0042 (13) | −0.0004 (14) | 0.0079 (14) |
N3 | 0.0281 (17) | 0.0259 (15) | 0.032 (2) | −0.0018 (12) | 0.0005 (14) | 0.0012 (13) |
N11 | 0.0357 (18) | 0.0218 (14) | 0.0272 (19) | 0.0028 (12) | −0.0019 (14) | 0.0021 (12) |
N12 | 0.0402 (18) | 0.0241 (14) | 0.027 (2) | 0.0018 (13) | 0.0033 (14) | 0.0005 (12) |
N21 | 0.046 (2) | 0.043 (2) | 0.043 (3) | 0.0013 (16) | 0.0066 (17) | −0.0014 (16) |
N31 | 0.040 (2) | 0.050 (2) | 0.042 (3) | 0.0078 (16) | −0.0081 (17) | −0.0064 (17) |
CN32 | 0.0368 (19) | 0.0371 (18) | 0.025 (2) | 0.0106 (15) | −0.0008 (15) | 0.0013 (14) |
C11 | 0.035 (2) | 0.0258 (16) | 0.025 (2) | 0.0011 (14) | −0.0008 (15) | 0.0008 (14) |
C12 | 0.036 (2) | 0.0248 (16) | 0.021 (2) | −0.0018 (14) | −0.0006 (15) | 0.0001 (14) |
C21 | 0.037 (2) | 0.038 (2) | 0.027 (2) | −0.0025 (16) | 0.0026 (17) | 0.0025 (16) |
C31 | 0.036 (2) | 0.0295 (18) | 0.029 (2) | 0.0061 (15) | −0.0073 (16) | −0.0076 (15) |
C1 | 0.031 (2) | 0.055 (3) | 0.034 (3) | −0.0067 (19) | 0.0025 (18) | 0.010 (2) |
C2 | 0.035 (2) | 0.074 (3) | 0.027 (3) | −0.003 (2) | 0.0037 (18) | 0.021 (2) |
C3 | 0.037 (2) | 0.063 (3) | 0.026 (3) | 0.007 (2) | −0.0044 (18) | 0.001 (2) |
C4 | 0.031 (2) | 0.052 (3) | 0.034 (3) | −0.0059 (18) | −0.0073 (17) | 0.0041 (19) |
Ag1—Ag2 | 3.2970 (4) | N31—C31 | 1.141 (5) |
Ag1—Ag3 | 3.1635 (6) | C12—N12i | 1.143 (4) |
Ag1—C11 | 2.074 (4) | C1—C2 | 1.520 (7) |
Ag1—C12 | 2.075 (3) | C3—C4 | 1.499 (7) |
Ag2—C21 | 2.082 (4) | N1—H1B | 0.86 (5) |
Ag3—C31 | 2.065 (4) | N1—H1A | 0.89 (4) |
Cu—N1 | 2.014 (3) | N2—H2 | 0.97 (4) |
Cu—N2 | 2.032 (3) | N3—H3A | 0.88 (5) |
Cu—N3 | 2.026 (3) | N3—H3B | 0.85 (5) |
Cu—N11 | 1.988 (3) | C1—H1C | 0.96 (5) |
Cu—N12 | 2.170 (3) | C1—H1D | 0.83 (5) |
N1—C1 | 1.486 (5) | C2—H2A | 1.07 (5) |
N2—C2 | 1.487 (5) | C2—H2B | 0.77 (5) |
N2—C3 | 1.469 (6) | C3—H3C | 0.94 (5) |
N3—C4 | 1.470 (5) | C3—H3D | 0.92 (5) |
N11—C11 | 1.152 (5) | C4—H4A | 0.94 (5) |
N21—C21 | 1.142 (5) | C4—H4B | 1.04 (5) |
C11—Ag1—C12 | 169.69 (15) | Cu—N3—H3A | 107 (3) |
C11—Ag1—Ag3 | 69.78 (11) | C4—N3—H3B | 110 (3) |
C12—Ag1—Ag3 | 102.90 (11) | Cu—N3—H3B | 106 (3) |
C11—Ag1—Ag2 | 116.42 (11) | H3A—N3—H3B | 110 (4) |
C12—Ag1—Ag2 | 71.78 (11) | C11—N11—Cu | 164.2 (3) |
Ag3—Ag1—Ag2 | 103.543 (14) | C12iii—N12—Cu | 167.7 (3) |
C21—Ag2—C21ii | 180.0 | N11—C11—Ag1 | 172.6 (3) |
C21—Ag2—Ag1ii | 67.58 (12) | N12i—C12—Ag1 | 177.2 (3) |
C21—Ag2—Ag1 | 112.42 (12) | N21—C21—Ag2 | 174.3 (4) |
C31—Ag3—Ag1 | 101.54 (12) | N31—C31—Ag3 | 174.5 (4) |
N11—Cu—N1 | 95.89 (13) | N1—C1—C2 | 107.3 (4) |
N11—Cu—N3 | 91.11 (13) | N1—C1—H1C | 107 (3) |
N1—Cu—N3 | 158.13 (15) | C2—C1—H1C | 115 (3) |
N11—Cu—N2 | 164.12 (14) | N1—C1—H1D | 112 (4) |
N1—Cu—N2 | 84.36 (13) | C2—C1—H1D | 103 (4) |
N3—Cu—N2 | 83.34 (14) | H1C—C1—H1D | 113 (5) |
N11—Cu—N12 | 102.07 (13) | N2—C2—C1 | 107.1 (4) |
N1—Cu—N12 | 100.33 (14) | N2—C2—H2A | 104 (3) |
N3—Cu—N12 | 98.41 (14) | C1—C2—H2A | 110 (3) |
N2—Cu—N12 | 93.47 (13) | N2—C2—H2B | 107 (4) |
C1—N1—Cu | 109.1 (3) | C1—C2—H2B | 110 (4) |
C1—N1—H1A | 113 (3) | H2A—C2—H2B | 118 (5) |
Cu—N1—H1A | 104 (3) | N2—C3—C4 | 107.3 (4) |
C1—N1—H1B | 109 (3) | N2—C3—H3C | 104 (3) |
Cu—N1—H1B | 115 (3) | C4—C3—H3C | 115 (3) |
H1A—N1—H1B | 106 (4) | N2—C3—H3D | 102 (3) |
C3—N2—C2 | 116.9 (4) | C4—C3—H3D | 109 (3) |
C3—N2—Cu | 108.7 (3) | H3C—C3—H3D | 117 (4) |
C2—N2—Cu | 108.5 (3) | N3—C4—C3 | 108.7 (4) |
C3—N2—H2 | 102 (3) | N3—C4—H4A | 108 (3) |
C2—N2—H2 | 116 (3) | C3—C4—H4A | 104 (3) |
Cu—N2—H2 | 104 (3) | N3—C4—H4B | 108 (3) |
C4—N3—Cu | 109.8 (2) | C3—C4—H4B | 110 (3) |
C4—N3—H3A | 114 (3) | H4A—C4—H4B | 119 (4) |
Symmetry codes: (i) −x+1/2, y+1/2, −z+1/2; (ii) −x, −y+1, −z; (iii) −x+1/2, y−1/2, −z+1/2. |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···N21iv | 0.89 (5) | 2.29 (5) | 3.119 (5) | 154 (4) |
N1—H1B···N31v | 0.86 (5) | 2.20 (5) | 3.055 (5) | 175 (4) |
N2—H2···N12 | 0.97 (4) | 2.70 (5) | 3.061 (5) | 103 (3) |
N3—H3B···N31 | 0.85 (5) | 2.39 (5) | 3.194 (5) | 159 (4) |
N3—H3A···N21iii | 0.88 (5) | 2.35 (5) | 3.189 (5) | 161 (4) |
Symmetry codes: (iii) −x+1/2, y−1/2, −z+1/2; (iv) −x, −y+1, −z+1; (v) x−1/2, −y+1/2, z−1/2. |
Experimental details
Crystal data | |
Chemical formula | [Cu(C4H13N3)Ag(CN)2]2[Ag(CN)2][Ag2(CN)3] |
Mr | 1106.96 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 293 |
a, b, c (Å) | 12.5588 (12), 17.8070 (12), 6.9608 (6) |
β (°) | 90.794 (11) |
V (Å3) | 1556.5 (2) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 4.45 |
Crystal size (mm) | 0.33 × 0.15 × 0.05 |
Data collection | |
Diffractometer | Stoe IPDS diffractometer |
Absorption correction | Numerical (SHELXTL; Sheldrick, 1995) |
Tmin, Tmax | 0.414, 0.809 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 18169, 4462, 2988 |
Rint | 0.056 |
(sin θ/λ)max (Å−1) | 0.709 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.031, 0.067, 0.88 |
No. of reflections | 4462 |
No. of parameters | 219 |
H-atom treatment | All H-atom parameters refined |
Δρmax, Δρmin (e Å−3) | 0.83, −0.65 |
Computer programs: EXPOSE in IPDS (Stoe & Cie, 1999), CELL in IPDS, INTEGRATE in IPDS, SHELXS86 (Sheldrick, 1985), SHELXL97 (Sheldrick, 1997), DIAMOND (Brandenburg, 1999).
Ag1—Ag2 | 3.2970 (4) | Cu—N2 | 2.032 (3) |
Ag1—Ag3 | 3.1635 (6) | Cu—N3 | 2.026 (3) |
Ag1—C11 | 2.074 (4) | Cu—N11 | 1.988 (3) |
Ag1—C12 | 2.075 (3) | Cu—N12 | 2.170 (3) |
Ag2—C21 | 2.082 (4) | N11—C11 | 1.152 (5) |
Ag3—C31 | 2.065 (4) | N21—C21 | 1.142 (5) |
Cu—N1 | 2.014 (3) | N31—C31 | 1.141 (5) |
C11—Ag1—C12 | 169.69 (15) | N11—Cu—N12 | 102.07 (13) |
N11—Cu—N1 | 95.89 (13) | N1—Cu—N12 | 100.33 (14) |
N11—Cu—N3 | 91.11 (13) | N3—Cu—N12 | 98.41 (14) |
N1—Cu—N3 | 158.13 (15) | N2—Cu—N12 | 93.47 (13) |
N11—Cu—N2 | 164.12 (14) | C11—N11—Cu | 164.2 (3) |
N1—Cu—N2 | 84.36 (13) | C12i—N12—Cu | 167.7 (3) |
N3—Cu—N2 | 83.34 (14) |
Symmetry code: (i) −x+1/2, y−1/2, −z+1/2. |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···N21ii | 0.89 (5) | 2.29 (5) | 3.119 (5) | 154 (4) |
N1—H1B···N31iii | 0.86 (5) | 2.20 (5) | 3.055 (5) | 175 (4) |
N2—H2···N12 | 0.97 (4) | 2.70 (5) | 3.061 (5) | 103 (3) |
N3—H3B···N31 | 0.85 (5) | 2.39 (5) | 3.194 (5) | 159 (4) |
N3—H3A···N21i | 0.88 (5) | 2.35 (5) | 3.189 (5) | 161 (4) |
Symmetry codes: (i) −x+1/2, y−1/2, −z+1/2; (ii) −x, −y+1, −z+1; (iii) x−1/2, −y+1/2, z−1/2. |
The magnetic properties of cyano complexes are currently the subject of intensive study (Verdaguer et al., 1999; Dunbar & Heintz, 1997). These complexes are suitable model compounds for the study of magnetic phenomena, due to the favourable properties of cyanometallate anions, i.e. the geometric and magnetic variability of the anions with various central atoms, the rigidity and stability of the anions, and the Lewis basicity of the N atoms, which facilitates the bridging function of the cyano group. The dicyanoargentate anion [NC—Ag—CN]-, with a linear geometry, may exhibit a bridging function, e.g. in the one-dimensional compound [Cd(N-Meim)4Ag(CN)2][Ag(CN)2] (N-Meim is N-methylimidazole; Soma & Iwamoto, 1996), although it can also act as a terminal ligand, e.g. in the dinuclear compound [N(Ph)4][ClPh3Sn—NC-AgCN] (Carcelli et al., 1992). In addition, it can simply play the role of counterion, as in [Ni(en)3][Ag(CN)2]2 (en is ethylenediamine; Kappenstein et al., 1988). A more complicated role is that which the cyanoargentate anion plays as part of the polymeric [Ag3(CN)5]2- anion (Zhang et al., 1999).
We are interested in the preparation, crystal chemistry and magnetic properties of low-dimensional cyanocomplexes. It is known that the CuII cation in these cyano complexes, apart from the usual 4 + 2 coordination, often exhibits pentacoordination. This property can be used in the synthetic design of one-dimensional polymeric species; when three coordination sites are blocked by a suitable 3 N-donor ligand, the presence of cyanometallate anions can lead to the formation of one-dimensional structures, e.g. in [Cu(dien)]3[Fe(CN)6]2·6H2O (Kou et al., 1997). Following this idea, we reacted dien as a 3 N-donor ligand with CuII, and added dicyanoargentate anions with the intention that they would be a bridging species. By this reaction, the title compound, (I), was formed and herein we report its crystal structure. \sch
The structure of (I) is formed from [–Cu(dien)-NC—Ag—CN–]nn+ cationic zigzag chains running parallel along the y axis (Fig. 1). The positive charge of these chains is counterbalanced by two different noncoordinated centrosymmetric cyanoargentate anions lying on special positions (1), namely one dicyanoargentate anion [Ag(CN)2]- (Ag2) and one tricyanodiargentate anion [Ag2(CN)3]- (Ag3).
The CuII cation exhibits pentacoordination in a form close to a deformed square pyramid, as is indicated by the the τ parameter of 10.2 (Addison et al., 1984). As expected, three coordination sites in the basal plane are occupied by the chelate-bonded dien ligand, and the remaining two sites, one in the basal plane and the apical one, are occupied by the N atoms of the bridging cyano groups. The Cu—N distances in the basal plane (Table 1) are very similar despite the different nature of the ligands, with a mean value of 2.02 (2) Å, while the ligand in the apical position is at a longer distance of 2.170 (3) Å. The Cu atom is displaced by 0.3052 (4) Å from the mean basal plane toward the apical ligand. The geometric parameters of the dien ligand in (I) are similar to those found in similar compounds (Rodriguez et al., 1999). The presence of the dien ligand manifests itself by various IR absorption bands due to ν(NH2), ν(CH2) and other types of vibrations. These are listed in the Experimental section. It is interesting to note that the electronic spectrum in the solid state exhibits only a single absorption band at 16300 cm-1. This displays only very weak asymmetry, which may indicate the presence of the shoulder on the lower energy side, as expected in such coordination (Lever, 1984). The possible assignment(s) to the observed absorption band envelope can be 2E← 2B1 and 2B← 2B1.
The tricyanodiargentate anion is found as a bridging species in some cyano complexes with Cd, e.g. [Cd(4-Mepy)4Ag2(CN)3] (4-Mepy is 4-methylpyridine; Soma & Iwamoto, 1994) and [Cd(pyz){Ag2(CN)3}{Ag(CN)2}] (pyz is pyrazine; Soma et al., 1994). In (I), the tricyanodiargentate anion is `unbound' and is centrosymmetric. As a consequence, the cyano group linking the two Ag atoms is disordered (label CN32). The geometric parameters associated with the dicyanoargentate and tricyanodiargentate anions in (I) are unremarkable (Soma & Iwamoto, 1994). The Ag2 anion is perfectly linear (Ag2 lies on the symmetry centre), while the Ag1 and Ag3 anions are somewhat bent at atoms Ag1 and Ag3. The presence of crystallographically different cyano groups can be seen in the IR spectrum of (I). The absorption bands at 2118 and 2133 cm-1 can be ascribed to the stretching vibrations of terminal cyano groups, while the remaining two absorption bands at 2156 and 2165 cm-1 are due to the presence of bridging cyano groups.
Argentophilic interactions (Omary et al., 1998) are responsible for the supramolecular architecture of the structure of (I) (Fig. 2). The Ag···Ag distances exhibit relatively short values (Table 1) compared with the Ag—Ag distance of 2.89 Å in metallic silver (Wells, 1984), but comparable with those found in similar compounds (Meske & Babel, 1988). If we also take into consideration the Ag2···Ag3 contacts of 3.5373 (5) Å, the Ag atoms form chains based on interconnected hexagons and extended along the c direction. Besides these argentophilic interactions, weak NH···N hydrogen bonds between the terminal N atoms of the cyano groups and the NH groups from the amine ligand contribute to the packing mode of the structure (Table 2).
The outstanding feature of the structure of (I) is the one-dimensional character of the polymeric cation. This can be classified as of the CT type (Černák et al., 2002), as the bridging cyano groups are in neighbouring cis positions at the pentacoordinated CuII cation and in trans positions (forced by the geometry of the anion) on the AgI cation. Such a type of chain among dicyanoargentates was previously found only in [Cu(bipy)2Ag2(CN)4]·H2O, where the cis positions of the bridging cyano groups in the 4 + 1+1 type coordination polyhedron of the Cu atom are forced by the presence of sterically demanding bipy ligands (bipy is 2,2'-bipyridine; Černák et al., 1993).