Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270103010151/tr1059sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270103010151/tr1059Isup2.hkl |
CCDC reference: 214383
For the preparation of (I), a blue precipitate containing [Cu(dabn)2]2+ cations, formed by mixing aqueous copper sulfate (0.1 M, 10 ml, 1 mmol) and aqueous 1,4-diaminobutane (2 M, 1 ml, 2 mmol), was dissolved by the addition of concentrated ammonia solution (26%, 1.5 ml). The resulting blue solution was mixed with aqueous K[Ag(CN)2] (0.2 M, 10 ml, 2 mmol), and the resulting blue solution was left to crystallize. Blue crystals of (I) suitable for X-ray analysis were obtained after 2 d. The crystals were filtered off and dried in air.
All diaminobutane H-atom positions were calculated using appropriate riding models and refined with isotropic displacement parameters 1.2 times larger than the displacement parameters of the parent C or N atoms, while water H-atom positions were found in a difference map and refined with free isotropic displacement parameters. Several peaks localized closer than 1 Å from either Ag or Cu atoms, with residual electron density about ±1 e Å−3, were found in the difference map.
Data collection: STADI4 Diffractometer Control and Data Collection Software 1.06 (Stoe & Cie, 1996); cell refinement: STADI4 Diffractometer Control and Data Collection Software 1.06; data reduction: X-RED 1.07 STOE Data Reduction Program (Stoe & Cie, 1996); program(s) used to solve structure: SHELXS86 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 2000); software used to prepare material for publication: SHELXL97.
[Cu2Ag4(CN)8(C4H12N2)2(NH3)]·2H2O | F(000) = 960 |
Mr = 996.10 | Dx = 2.172 Mg m−3 |
Monoclinic, P2/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yc | Cell parameters from 20 reflections |
a = 9.862 (6) Å | θ = 8.1–11.6° |
b = 16.541 (5) Å | µ = 3.93 mm−1 |
c = 10.210 (12) Å | T = 293 K |
β = 113.84 (4)° | Prism, blue |
V = 1523 (2) Å3 | 0.45 × 0.22 × 0.15 mm |
Z = 2 |
STOE-STADI-IV diffractometer | 2160 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.062 |
Graphite monochromator | θmax = 25.0°, θmin = 2.3° |
θ/2θ scans | h = −11→11 |
Absorption correction: ψ scan North et al., 1968 | k = −19→0 |
Tmin = 0.422, Tmax = 0.619 | l = −12→12 |
5248 measured reflections | 2 standard reflections every 60 min min |
2694 independent reflections | intensity decay: none |
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)] = 0.042 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.113 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.05 | w = 1/[σ2(Fo2) + (0.0564P)2 + 0.251P] where P = (Fo2 + 2Fc2)/3 |
2694 reflections | (Δ/σ)max < 0.001 |
180 parameters | Δρmax = 1.10 e Å−3 |
2 restraints | Δρmin = −1.14 e Å−3 |
[Cu2Ag4(CN)8(C4H12N2)2(NH3)]·2H2O | V = 1523 (2) Å3 |
Mr = 996.10 | Z = 2 |
Monoclinic, P2/c | Mo Kα radiation |
a = 9.862 (6) Å | µ = 3.93 mm−1 |
b = 16.541 (5) Å | T = 293 K |
c = 10.210 (12) Å | 0.45 × 0.22 × 0.15 mm |
β = 113.84 (4)° |
STOE-STADI-IV diffractometer | 2160 reflections with I > 2σ(I) |
Absorption correction: ψ scan North et al., 1968 | Rint = 0.062 |
Tmin = 0.422, Tmax = 0.619 | 2 standard reflections every 60 min min |
5248 measured reflections | intensity decay: none |
2694 independent reflections |
R[F2 > 2σ(F2)] = 0.042 | 2 restraints |
wR(F2) = 0.113 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.05 | Δρmax = 1.10 e Å−3 |
2694 reflections | Δρmin = −1.14 e Å−3 |
180 parameters |
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) | |
Ag3 | 0.5000 | 0.64008 (4) | 0.2500 | 0.05118 (19) | |
C5 | 0.7169 (6) | 0.6243 (4) | 0.3987 (6) | 0.0442 (14) | |
N5 | 0.8258 (6) | 0.6069 (4) | 0.4806 (6) | 0.0604 (16) | |
Cu2 | 1.0000 | 0.58158 (5) | 0.7500 | 0.0434 (3) | |
N7 | 1.0000 | 0.7032 (4) | 0.7500 | 0.0422 (16) | |
H7A | 0.9968 | 0.7211 | 0.6666 | 0.063* | 0.50 |
H7B | 1.0821 | 0.7211 | 0.8207 | 0.063* | 0.50 |
H7C | 0.9211 | 0.7211 | 0.7627 | 0.063* | 0.50 |
N8 | 1.1556 (4) | 0.5788 (3) | 0.6668 (5) | 0.0383 (11) | |
H8A | 1.1358 | 0.5361 | 0.6072 | 0.046* | |
H8B | 1.1443 | 0.6235 | 0.6132 | 0.046* | |
C8 | 1.3128 (5) | 0.5738 (3) | 0.7673 (6) | 0.0345 (12) | |
H8C | 1.3284 | 0.5236 | 0.8206 | 0.041* | |
H8D | 1.3347 | 0.6180 | 0.8352 | 0.041* | |
C9 | 1.4190 (5) | 0.5772 (3) | 0.6954 (6) | 0.0369 (13) | |
H9A | 1.4001 | 0.6257 | 0.6374 | 0.044* | |
H9B | 1.4023 | 0.5310 | 0.6323 | 0.044* | |
N2 | 1.0000 | 0.4609 (5) | 0.7500 | 0.060 (2) | |
C2 | 1.0000 | 0.3927 (5) | 0.7500 | 0.059 (2) | |
Ag1 | 1.0000 | 0.26818 (4) | 0.7500 | 0.0665 (2) | |
C1 | 1.0000 | 0.1437 (5) | 0.7500 | 0.054 (2) | |
N1 | 1.0000 | 0.0748 (4) | 0.7500 | 0.0524 (19) | |
Cu1 | 1.0000 | −0.04769 (5) | 0.7500 | 0.0270 (2) | |
N6 | 1.1606 (4) | −0.0491 (3) | 0.6761 (5) | 0.0309 (9) | |
H6A | 1.1620 | −0.0989 | 0.6412 | 0.037* | |
H6B | 1.1334 | −0.0147 | 0.6016 | 0.037* | |
C6 | 1.3148 (5) | −0.0287 (3) | 0.7738 (6) | 0.0331 (12) | |
H6C | 1.3498 | −0.0678 | 0.8512 | 0.040* | |
H6D | 1.3160 | 0.0241 | 0.8153 | 0.040* | |
C7 | 1.4194 (5) | −0.0282 (3) | 0.6982 (6) | 0.0362 (12) | |
H7D | 1.4002 | −0.0755 | 0.6370 | 0.043* | |
H7E | 1.3999 | 0.0193 | 0.6378 | 0.043* | |
N3 | 0.8740 (4) | −0.1142 (3) | 0.5746 (5) | 0.0393 (11) | |
C3 | 0.8083 (6) | −0.1494 (4) | 0.4724 (6) | 0.0399 (13) | |
Ag2 | 0.68400 (5) | −0.20290 (3) | 0.27767 (5) | 0.05431 (15) | |
C4 | 0.5614 (7) | −0.2239 (4) | 0.0646 (7) | 0.0477 (15) | |
N4 | 0.4936 (7) | −0.2296 (4) | −0.0562 (6) | 0.0607 (15) | |
O1 | 0.2491 (5) | 0.7724 (3) | 0.6635 (5) | 0.0539 (11) | |
H1W | 0.306 (4) | 0.782 (3) | 0.743 (2) | 0.023 (14)* | |
H2W | 0.299 (3) | 0.776 (6) | 0.619 (3) | 0.10 (3)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Ag3 | 0.0335 (3) | 0.0421 (4) | 0.0656 (4) | 0.000 | 0.0073 (3) | 0.000 |
C5 | 0.034 (3) | 0.050 (3) | 0.044 (3) | 0.002 (2) | 0.011 (3) | −0.004 (3) |
N5 | 0.036 (3) | 0.075 (4) | 0.058 (3) | 0.006 (3) | 0.007 (3) | −0.016 (3) |
Cu2 | 0.0267 (4) | 0.0246 (5) | 0.0933 (7) | 0.000 | 0.0391 (5) | 0.000 |
N7 | 0.043 (3) | 0.035 (4) | 0.051 (4) | 0.000 | 0.022 (3) | 0.000 |
N8 | 0.0227 (18) | 0.037 (2) | 0.061 (3) | 0.0034 (17) | 0.022 (2) | 0.004 (2) |
C8 | 0.022 (2) | 0.033 (3) | 0.054 (3) | −0.0003 (19) | 0.021 (2) | 0.001 (2) |
C9 | 0.023 (2) | 0.034 (3) | 0.061 (3) | 0.007 (2) | 0.025 (2) | 0.010 (2) |
N2 | 0.057 (4) | 0.040 (4) | 0.109 (6) | 0.000 | 0.060 (4) | 0.000 |
C2 | 0.082 (5) | 0.024 (4) | 0.102 (7) | 0.000 | 0.069 (5) | 0.000 |
Ag1 | 0.0846 (5) | 0.0242 (3) | 0.1192 (6) | 0.000 | 0.0706 (5) | 0.000 |
C1 | 0.063 (5) | 0.027 (4) | 0.099 (7) | 0.000 | 0.063 (5) | 0.000 |
N1 | 0.057 (4) | 0.037 (4) | 0.089 (5) | 0.000 | 0.056 (4) | 0.000 |
Cu1 | 0.0159 (3) | 0.0290 (4) | 0.0397 (5) | 0.000 | 0.0148 (3) | 0.000 |
N6 | 0.0204 (17) | 0.038 (2) | 0.036 (2) | 0.0003 (16) | 0.0129 (17) | 0.0025 (18) |
C6 | 0.018 (2) | 0.040 (3) | 0.045 (3) | −0.0038 (19) | 0.017 (2) | −0.006 (2) |
C7 | 0.025 (2) | 0.044 (3) | 0.048 (3) | −0.001 (2) | 0.023 (2) | 0.005 (2) |
N3 | 0.0233 (19) | 0.047 (3) | 0.052 (3) | −0.0035 (18) | 0.019 (2) | −0.005 (2) |
C3 | 0.035 (3) | 0.040 (3) | 0.051 (3) | −0.003 (2) | 0.024 (3) | −0.001 (3) |
Ag2 | 0.0510 (3) | 0.0590 (3) | 0.0511 (3) | −0.0162 (2) | 0.0187 (2) | −0.0172 (2) |
C4 | 0.055 (3) | 0.045 (3) | 0.052 (4) | −0.009 (3) | 0.031 (3) | −0.012 (3) |
N4 | 0.068 (3) | 0.060 (4) | 0.058 (4) | −0.005 (3) | 0.029 (3) | −0.010 (3) |
O1 | 0.046 (2) | 0.053 (3) | 0.069 (3) | −0.001 (2) | 0.030 (2) | −0.002 (2) |
Ag3—C5i | 2.080 (6) | Ag1—C1 | 2.059 (8) |
Ag3—C5 | 2.080 (6) | C1—N1 | 1.140 (11) |
Ag3—Ag2ii | 3.1152 (12) | N1—Cu1 | 2.026 (7) |
Ag3—Ag2iii | 3.1152 (12) | Cu1—N6iv | 2.011 (4) |
C5—N5 | 1.099 (7) | Cu1—N6 | 2.011 (4) |
Cu2—N2 | 1.997 (8) | Cu1—N3 | 2.040 (5) |
Cu2—N7 | 2.011 (6) | Cu1—N3iv | 2.040 (5) |
Cu2—N8iv | 2.033 (4) | N6—C6 | 1.482 (6) |
Cu2—N8 | 2.033 (4) | N6—H6A | 0.9000 |
N7—H7A | 0.8900 | N6—H6B | 0.9000 |
N7—H7B | 0.8900 | C6—C7 | 1.517 (7) |
N7—H7C | 0.8900 | C6—H6C | 0.9700 |
N8—C8 | 1.475 (6) | C6—H6D | 0.9700 |
N8—H8A | 0.9000 | C7—C7v | 1.511 (9) |
N8—H8B | 0.9000 | C7—H7D | 0.9700 |
C8—C9 | 1.503 (7) | C7—H7E | 0.9700 |
C8—H8C | 0.9700 | N3—C3 | 1.141 (7) |
C8—H8D | 0.9700 | C3—Ag2 | 2.066 (6) |
C9—C9v | 1.535 (10) | Ag2—C4 | 2.047 (7) |
C9—H9A | 0.9700 | Ag2—Ag3vi | 3.1152 (12) |
C9—H9B | 0.9700 | C4—N4 | 1.144 (8) |
N2—C2 | 1.128 (11) | O1—H1W | 0.795 (10) |
C2—Ag1 | 2.059 (8) | O1—H2W | 0.799 (10) |
C5i—Ag3—C5 | 165.6 (3) | C2—Ag1—C1 | 180.000 (2) |
C5i—Ag3—Ag2ii | 124.10 (17) | N1—C1—Ag1 | 180.000 (1) |
C5—Ag3—Ag2ii | 69.45 (18) | C1—N1—Cu1 | 180.000 (1) |
C5i—Ag3—Ag2iii | 69.45 (18) | N6iv—Cu1—N6 | 178.7 (3) |
C5—Ag3—Ag2iii | 124.10 (17) | N6iv—Cu1—N1 | 90.66 (13) |
Ag2ii—Ag3—Ag2iii | 67.02 (4) | N6—Cu1—N1 | 90.66 (13) |
N5—C5—Ag3 | 171.3 (6) | N6iv—Cu1—N3 | 91.73 (18) |
N2—Cu2—N7 | 180 | N6—Cu1—N3 | 87.55 (18) |
N2—Cu2—N8iv | 88.69 (13) | N1—Cu1—N3 | 122.65 (14) |
N7—Cu2—N8iv | 91.31 (13) | N6iv—Cu1—N3iv | 87.55 (18) |
N2—Cu2—N8 | 88.69 (13) | N6—Cu1—N3iv | 91.73 (18) |
N7—Cu2—N8 | 91.31 (13) | N1—Cu1—N3iv | 122.65 (14) |
N8iv—Cu2—N8 | 177.4 (3) | N3—Cu1—N3iv | 114.7 (3) |
Cu2—N7—H7A | 109.5 | C6—N6—Cu1 | 119.7 (3) |
Cu2—N7—H7B | 109.5 | C6—N6—H6A | 107.4 |
H7A—N7—H7B | 109.5 | Cu1—N6—H6A | 107.4 |
Cu2—N7—H7C | 109.5 | C6—N6—H6B | 107.4 |
H7A—N7—H7C | 109.5 | Cu1—N6—H6B | 107.4 |
H7B—N7—H7C | 109.5 | H6A—N6—H6B | 106.9 |
C8—N8—Cu2 | 118.0 (4) | N6—C6—C7 | 112.5 (4) |
C8—N8—H8A | 107.8 | N6—C6—H6C | 109.1 |
Cu2—N8—H8A | 107.8 | C7—C6—H6C | 109.1 |
C8—N8—H8B | 107.8 | N6—C6—H6D | 109.1 |
Cu2—N8—H8B | 107.8 | C7—C6—H6D | 109.1 |
H8A—N8—H8B | 107.2 | H6C—C6—H6D | 107.8 |
N8—C8—C9 | 113.7 (5) | C7v—C7—C6 | 112.5 (6) |
N8—C8—H8C | 108.8 | C7v—C7—H7D | 109.1 |
C9—C8—H8C | 108.8 | C6—C7—H7D | 109.1 |
N8—C8—H8D | 108.8 | C7v—C7—H7E | 109.1 |
C9—C8—H8D | 108.8 | C6—C7—H7E | 109.1 |
H8C—C8—H8D | 107.7 | H7D—C7—H7E | 107.8 |
C8—C9—C9v | 111.8 (6) | C3—N3—Cu1 | 175.8 (5) |
C8—C9—H9A | 109.3 | N3—C3—Ag2 | 174.7 (5) |
C9v—C9—H9A | 109.3 | C4—Ag2—C3 | 164.0 (2) |
C8—C9—H9B | 109.3 | C4—Ag2—Ag3vi | 71.96 (17) |
C9v—C9—H9B | 109.3 | C3—Ag2—Ag3vi | 122.80 (16) |
H9A—C9—H9B | 107.9 | N4—C4—Ag2 | 174.9 (6) |
C2—N2—Cu2 | 180.000 (1) | H1W—O1—H2W | 103 (4) |
N2—C2—Ag1 | 180.000 (1) | ||
N2—Cu2—N8—C8 | −87.1 (4) | N3—Cu1—N6—C6 | −162.9 (4) |
N7—Cu2—N8—C8 | 92.9 (4) | N3iv—Cu1—N6—C6 | −48.3 (4) |
Cu2—N8—C8—C9 | −176.4 (3) | Cu1—N6—C6—C7 | −176.8 (4) |
N8—C8—C9—C9v | 176.4 (3) | N6—C6—C7—C7v | −165.7 (3) |
N1—Cu1—N6—C6 | 74.4 (4) |
Symmetry codes: (i) −x+1, y, −z+1/2; (ii) x, y+1, z; (iii) −x+1, y+1, −z+1/2; (iv) −x+2, y, −z+3/2; (v) −x+3, y, −z+3/2; (vi) x, y−1, z. |
Experimental details
Crystal data | |
Chemical formula | [Cu2Ag4(CN)8(C4H12N2)2(NH3)]·2H2O |
Mr | 996.10 |
Crystal system, space group | Monoclinic, P2/c |
Temperature (K) | 293 |
a, b, c (Å) | 9.862 (6), 16.541 (5), 10.210 (12) |
β (°) | 113.84 (4) |
V (Å3) | 1523 (2) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 3.93 |
Crystal size (mm) | 0.45 × 0.22 × 0.15 |
Data collection | |
Diffractometer | STOE-STADI-IV diffractometer |
Absorption correction | ψ scan North et al., 1968 |
Tmin, Tmax | 0.422, 0.619 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5248, 2694, 2160 |
Rint | 0.062 |
(sin θ/λ)max (Å−1) | 0.596 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.042, 0.113, 1.05 |
No. of reflections | 2694 |
No. of parameters | 180 |
No. of restraints | 2 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 1.10, −1.14 |
Computer programs: STADI4 Diffractometer Control and Data Collection Software 1.06 (Stoe & Cie, 1996), STADI4 Diffractometer Control and Data Collection Software 1.06, X-RED 1.07 STOE Data Reduction Program (Stoe & Cie, 1996), SHELXS86 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), DIAMOND (Brandenburg, 2000), SHELXL97.
Ag3—C5 | 2.080 (6) | C1—N1 | 1.140 (11) |
Ag3—Ag2i | 3.1152 (12) | N1—Cu1 | 2.026 (7) |
C5—N5 | 1.099 (7) | Cu1—N6 | 2.011 (4) |
Cu2—N2 | 1.997 (8) | Cu1—N3 | 2.040 (5) |
Cu2—N7 | 2.011 (6) | N3—C3 | 1.141 (7) |
Cu2—N8 | 2.033 (4) | C3—Ag2 | 2.066 (6) |
N2—C2 | 1.128 (11) | Ag2—C4 | 2.047 (7) |
C2—Ag1 | 2.059 (8) | C4—N4 | 1.144 (8) |
Ag1—C1 | 2.059 (8) | ||
C5ii—Ag3—C5 | 165.6 (3) | N6iii—Cu1—N6 | 178.7 (3) |
N5—C5—Ag3 | 171.3 (6) | N6—Cu1—N1 | 90.66 (13) |
N2—Cu2—N7 | 180 | N6iii—Cu1—N3 | 91.73 (18) |
N2—Cu2—N8 | 88.69 (13) | N6—Cu1—N3 | 87.55 (18) |
N7—Cu2—N8 | 91.31 (13) | N1—Cu1—N3 | 122.65 (14) |
N8iii—Cu2—N8 | 177.4 (3) | N3—Cu1—N3iii | 114.7 (3) |
Symmetry codes: (i) x, y+1, z; (ii) −x+1, y, −z+1/2; (iii) −x+2, y, −z+3/2. |
D-H···A | D···A | H···A | D-H···A |
N7-H7C···O1i | 3.143 (2) | 2.265 (1) | 169.36 (7) |
N6-H6A···O1ii | 3.096 (1) | 2.272 (1) | 152.07 (5) |
O1-H1W···N4iii | 2.903 (3) | 2.143 (2) | 159.87 (7) |
O1-H2W···N4iv | 3.144 (2) | 2.376 (1) | 161.63 (8) |
Symmetry codes: (i) 1 − x,y,3/2 − z; (ii) 1 + x,-1 + y,z; (iii) x,1 + y,1 + z; (iv) 1 − x,1 + y,1/2 − z |
Cyanocomplexes unceasingly attract much attention within coordination chemistry, because of the diversity of the crystal structures formed and their interesting properties, especially in the context of their magnetic behavior (Iwamoto, 1996; Verdaguer et al., 1999; Ohba & Okawa, 2000; Černák et al. 2002). Dicyanoargentate complexes are mainly investigated from the structural and magnetochemical point of view (Iwamoto, 1996; Comte et al., 2000; Shek et al., 2000; Assefa et al., 1995; Dasna et al., 2001; Zhang et al., 2002). The interest of our research group has been mainly focused on the preparation and study of low-dimensional magnetics (Černák et al., 2002) and the present contribution is a continuation of our study of compounds exhibiting the general formula Cu(L)2Ag2(CN)4, where L is either a bidentate chelating ligand, viz. 1,2-diaminoethane (Černák et al., 1998), 1,3-diaminopropane (Černák et al., 2000) and 1,2- diaminopropane (Triščíková et al., 2003a)], or the monodentate 4-methylpyridine ligand (Triščíková et al., 2002)]. With the aim of examining the effect of replacing the above bidentate ligands by somewhat larger ligands on the structure, we have used in our synthesis 1,4-diaminobutane (dabn). As a result, the title compound, {Cu2(dabn)2[Ag(CN)2]4NH3}·2H2O, (I), has been prepared, and we present here its crystal structure.
There are two crystallographically different Cu atoms in the structure of (I) (Fig. 1). Atom Cu1 is pentacoordinated in the form of a slightly distorted trigonal bipyramid by two monodentate Ag(CN)2− anions (atoms Ag2) in the equatorial plane and by two bridging diaminobutane ligands in the axial positions, which connect neighboring Cu1 atoms to form an infinite chain parallel to [100]. The third equatorial position is occupied by a bridging Ag(CN)2− anion (atom Ag1), which links atoms Cu1 and Cu2. Relatively small deviations of bond angles around the Cu1 atom from the corresponding values for the ideal trigonal bipyramid indicate that the degree of polyhedral distortion is small, as confirmed by the τ-parameter (Addison et al., 1984) of 93.4 (ideal values are 100 for a trigonal bipyramid and 0 for a square pyramid). In accordance with this statement, if we assign α3 to the N3—Cu1—N3 angle and α1 and α2 to the other two angles in the equatorial plane, then according to criteria of Harrison & Hathaway (1980), which are based on the values of the three equatorial angles and their differences, the shape of the coordination polyhedron around atom Cu1 can be described as trigonal bipyramidal with C2v symmetry. The C2 axis passes through atom Cu1, the whole of the bridging Ag(CN)2− anion, atom Cu2 and atom N7 of the ammonia molecule coordinated to atom Cu2. Atom Cu2 is hexacoordinated by three dicyanoargentate anions, the ammonia molecule and two diaminobutane molecules and, as a consequence of the Jahn–Teller effect, its coordination polyhedron adopts the shape of an elongated tetragonal bipyramid, with dicyanoargentate anions (atoms Ag3) in axial positions [2 τimes Cu2—N5 = 2.622 (6) Å], while the four equatorial Cu—N bonds range from 1.997 (8) to 2.033 (4) Å. Only one N atom (ammonia atom N7) in the coordination sphere of atom Cu2 originates from a monodentate ligand. The two diaminobutane ligands and all three Ag(CN)2− anions are bridging. The two diaminobutane ligands connect neighboring Cu2 atoms to form infinite chains, parallel with the chain containing atoms Cu1. Atoms Cu2 from the neighbouring chains are connected through the two Ag(CN)2− anions (atoms Ag3) to form a chain parallel to [001] and, as mentioned above, one Ag(CN)2− anion (Ag1 atom) connects atoms Cu1 and Cu2. Thus, atoms Cu2 lie in a plane parallel to (010), which is formed by chains parallel to [100] and [001]. Ammonia molecules stand perpendicular to this plane and in the trans position, and Ag(CN)2− anions connecting atoms Cu1 and Cu2 hang from the plane (Fig. 2). Finally, we can describe the structure of (I) as a unique combination of two- dimensional plane with one-dimensional chains, both forming one layer. Water molecules remain uncoordinated and are involved in hydrogen bonds with N atoms of an Ag(CN)2− anion (atom Ag2) and the diaminobutane molecule (Table 2).
There are one type of monodentate and two different types of bridging Ag(CN)2− anions in the structure of (I). The co-existence of both bridging and monodentate Ag(CN)2− anions in one compound is not common. Nevertheless, it has been observed in [Cd(4-ampy)2{µ- Ag(CN)2}2][Cd(mea)(4-ampy){Ag(CN)2}{µ-Ag(CN)2}]2 (4-ampy is 4-aminopyridine and mea = 2-aminoethanol; Soma & Iwamoto, 1996a), [Cu(4- Mepy)2Ag2(CN)4] (Triščíková et al., 2002) and [CuII(4- Mepy)3Ag2 − xCuIx(CN)4] (x = 0.07; 4-Mepy is 4-methylpyridine; Triščíková et al., 2003b). Dicyanoargentates with the general formula Cu(L)2Ag2(CN)4 [L is 1,2-diaminoethane (Černák et al., 1998) or 2,2'-bipyridine (Černák et al., 1993)], are one- dimensional polymers that contain one bridging and one isolated Ag(CN)2− anion. In contrast, the compound where L is 1,3- diaminopropane contains non-polymeric binuclear cations, also with one isolated and one monodentate Ag(CN)2− anion (Černák et al., 2000) and the compound where L is 1,2-diaminopropane (pn) is built up of the trinuclear NC—Ag—CN—-Cu(pn)2—NC—Ag—CN molecules and contains only monodentate Ag(CN)2− anions (Triščíková et al., 2003a).
There are no unusual features in the bond lengths of the dicyanoargentate anions in (I). Although they are differently ligated, equivalent bond lengths are almost equal. On the other hand, the Ag1 dicyanoargentate anion localized on a rotation axis is perfectly linear, but the Ag2 and Ag3 dicyanoargentate anions are substantially bent from linearity. Particularly the angles around atoms Ag1 and Ag3 are far from the linearity. Moreover, the bonding mode of the Ag3 dicyanoargentate anion can be considered as angular [C5—N5—Cu2 = 149.8 (4)°].
The bending of the two dicyanoargentate anions in (I) may be explained by argentophilic interactions between atoms Ag2 and Ag3 (Fig. 2), which are characteristic of dicyanoragentates (Omary et al., 1998; Soma & Iwamoto, 1996b; Soma & Iwamoto, 1994; Soma et al., 1994; Černák et al., 1998). A typical range for these Ag···Ag contacts is ca 3.05– 3.26 Å, but both shorter [2.9264 (5) Å; Triščíková et al., 2003b] and longer [3.899 (1) Å; Omary et al., 1998] contacts have been reported. In (I), the Ag2···Ag3 distance is 3.1152 (12) Å, and these argentophilic interactions connect the Cu1-containing chains from the upper layer with the Cu2-containing plane from the neighbouring lower layer, thus forming an infinite three-dimensional network.