Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270101006229/br1320sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270101006229/br1320Isup2.hkl |
CCDC reference: 169926
All reagents were of analytical grade and used without further purification. A mixture of NiCl2·6H2O (0.0880 g), NaVO3 (0.0904 g), 4,4'-bipyridyl (0.1157 g), (CH3)4NOH (0.0338 g) and H2O (10 ml) in a molar ratio 1:2:2:1:1500 was placed in a 20 ml Teflon-lined steel autoclave, and heated at 453 K for 72 h. After cooling to room temperature, green needle-like crystals were obtained in ca 70% yield based on vanadium (Found: H 3.18, C 35.09, N 8.20%; V 18.9, Ni 10.48%; calculated for Ni2V4O16.5C30N6H33: H 3.13, C 33.9, N 7.93, V 19.17, Ni 11.04%). The infrared spectrum exhibits absorption bands in the range 950–500 cm-1, attributed to V═O or V—O—V stretching, and additional bands in the range 1600–1000 cm-1 assigned to 4,4'-bipy groups. Thermal gravimetric analysis shows a weight loss of 5.8% between 293 and 533 K corresponding to water of crystallization, and a further loss of 34.9% occurred between 533 and 705 K due to elemination of water O3 and the decomposition of 4,4'-bipy.
H atoms were defined and refined only for the 4,4'-bipy groups. Positional and Uiso parameters for H14 were fixed because of their gradual divergence during the refinement. Crystallization water molecules O8, O9, and O10 were refined with occupancies of 1/2, 1/2, and 1/4, respectively, because of too large Uiso parameters when refined on full occupancies.
Data collection: PROCESS-AUTO (Rigaku Corporation, 1998); cell refinement: PROCESS-AUTO; data reduction: TEXSAN (Molecular Structure Corporation, 1985, 1989); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: TEXSAN; software used to prepare material for publication: TEXSAN.
[Ni2(V2O6)2(C10H8N2)3(H2O)2]·2.5H2O | Dx = 1.864 Mg m−3 |
Mr = 1062.79 | Mo Kα radiation, λ = 0.7107 Å |
Monoclinic, C2/c | Cell parameters from 14338 reflections |
a = 30.3799 (9) Å | θ = 1.9–30.0° |
b = 11.2402 (3) Å | µ = 2.00 mm−1 |
c = 11.5366 (3) Å | T = 173 K |
β = 105.961 (1)° | Prism, green |
V = 3787.6 (2) Å3 | 0.30 × 0.12 × 0.03 mm |
Z = 4 |
Rigaku RAXIS-RAPID Imaging Plate diffractometer | 4198 reflections with F2 > 2.0σ(F2) |
ω scans | Rint = 0.027 |
Absorption correction: multi-scan (Higashi, 1995) | θmax = 30.0° |
Tmin = 0.515, Tmax = 0.869 | h = −42→42 |
14250 measured reflections | k = −15→15 |
5509 independent reflections | l = −16→16 |
Refinement on F2 | H atoms treated by a mixture of independent and constrained refinement |
R[F2 > 2σ(F2)] = 0.042 | w = 1/[σ2(Fo2) + (0.05P)2] where P = (Fo2,0) + 2Fc2)/3) |
wR(F2) = 0.114 | (Δ/σ)max = 0.002 |
S = 1.40 | Δρmax = 0.90 e Å−3 |
4634 reflections | Δρmin = −0.50 e Å−3 |
312 parameters |
[Ni2(V2O6)2(C10H8N2)3(H2O)2]·2.5H2O | V = 3787.6 (2) Å3 |
Mr = 1062.79 | Z = 4 |
Monoclinic, C2/c | Mo Kα radiation |
a = 30.3799 (9) Å | µ = 2.00 mm−1 |
b = 11.2402 (3) Å | T = 173 K |
c = 11.5366 (3) Å | 0.30 × 0.12 × 0.03 mm |
β = 105.961 (1)° |
Rigaku RAXIS-RAPID Imaging Plate diffractometer | 5509 independent reflections |
Absorption correction: multi-scan (Higashi, 1995) | 4198 reflections with F2 > 2.0σ(F2) |
Tmin = 0.515, Tmax = 0.869 | Rint = 0.027 |
14250 measured reflections |
R[F2 > 2σ(F2)] = 0.042 | 312 parameters |
wR(F2) = 0.114 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.40 | Δρmax = 0.90 e Å−3 |
4634 reflections | Δρmin = −0.50 e Å−3 |
Refinement. Refinement using reflections with F2 > 1.0 σ(F2). The weighted R-factor (wR) and goodness of fit (S) are based on F2. R-factor (gt) are based on F. The threshold expression of F2 > 2.0 σ(F2) is used only for calculating R-factor (gt). |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
Ni1 | 0.2500 | 1.2500 | 0.5000 | 0.0155 (1) | |
Ni2 | 0.5000 | 0.5000 | 0.5000 | 0.0198 (1) | |
V1 | 0.39317 (2) | 0.41156 (5) | 0.32137 (4) | 0.0182 (1) | |
V2 | 0.35517 (2) | 0.40646 (5) | 0.56417 (4) | 0.0187 (1) | |
O1 | 0.29971 (7) | 0.3744 (2) | 0.5281 (2) | 0.0217 (5) | |
O2 | 0.38569 (10) | 0.2886 (3) | 0.6072 (3) | 0.0449 (8) | |
O3 | 0.47301 (8) | 0.4184 (3) | 0.6296 (2) | 0.0360 (7) | |
O4 | 0.44974 (8) | 0.4284 (3) | 0.3634 (2) | 0.0328 (7) | |
O5 | 0.36845 (8) | 0.4681 (3) | 0.4344 (2) | 0.0323 (7) | |
O6 | 0.3813 (1) | 0.2718 (3) | 0.3029 (3) | 0.0426 (8) | |
O7 | 0.36759 (8) | 0.4860 (3) | 0.1821 (2) | 0.0380 (7) | |
O8 | 0.4621 (4) | 0.175 (1) | 0.586 (1) | 0.134 (4)* | 0.50 |
O9 | 0.4730 (7) | 0.083 (2) | 0.433 (2) | 0.195 (7)* | 0.50 |
O10 | 0.5018 (8) | 0.012 (2) | 0.696 (2) | 0.108 (7)* | 0.25 |
N1 | 0.29958 (8) | 1.1124 (2) | 0.4988 (2) | 0.0199 (6) | |
N2 | 0.23974 (8) | 1.2679 (2) | 0.3017 (2) | 0.0189 (6) | |
N3 | 0.45849 (8) | 0.6503 (3) | 0.4951 (2) | 0.0235 (7) | |
C1 | 0.3238 (1) | 1.1127 (3) | 0.4189 (3) | 0.0281 (9) | |
C2 | 0.3556 (1) | 1.0261 (4) | 0.4142 (3) | 0.0283 (9) | |
C3 | 0.3644 (1) | 0.9345 (3) | 0.4971 (3) | 0.0227 (7) | |
C4 | 0.3396 (1) | 0.9351 (3) | 0.5833 (3) | 0.0280 (9) | |
C5 | 0.3082 (1) | 1.0240 (3) | 0.5805 (3) | 0.0260 (8) | |
C6 | 0.3977 (1) | 0.8386 (3) | 0.4947 (3) | 0.0239 (7) | |
C7 | 0.4035 (1) | 0.7933 (3) | 0.3881 (3) | 0.0282 (8) | |
C8 | 0.4337 (1) | 0.7004 (3) | 0.3924 (3) | 0.0272 (8) | |
C9 | 0.4528 (1) | 0.6947 (4) | 0.5970 (3) | 0.0370 (10) | |
C10 | 0.4238 (1) | 0.7883 (4) | 0.6011 (3) | 0.038 (1) | |
C11 | 0.26385 (10) | 1.3471 (3) | 0.2572 (3) | 0.0213 (7) | |
C12 | 0.2681 (1) | 1.3447 (3) | 0.1409 (3) | 0.0229 (7) | |
C13 | 0.24702 (10) | 1.2550 (3) | 0.0620 (2) | 0.0195 (7) | |
C14 | 0.2210 (1) | 1.1758 (3) | 0.1060 (3) | 0.0312 (9) | |
C15 | 0.2174 (1) | 1.1845 (3) | 0.2236 (3) | 0.0285 (9) | |
H1 | 0.320 (1) | 1.180 (4) | 0.359 (4) | 0.031 (10)* | |
H2 | 0.368 (2) | 1.042 (4) | 0.363 (4) | 0.05 (1)* | |
H3 | 0.341 (1) | 0.868 (4) | 0.636 (4) | 0.04 (1)* | |
H4 | 0.289 (1) | 1.025 (4) | 0.640 (4) | 0.04 (1)* | |
H7 | 0.382 (1) | 0.815 (4) | 0.310 (4) | 0.04 (1)* | |
H8 | 0.435 (1) | 0.654 (4) | 0.322 (4) | 0.04 (1)* | |
H9 | 0.471 (1) | 0.665 (4) | 0.669 (4) | 0.04 (1)* | |
H10 | 0.422 (1) | 0.805 (4) | 0.671 (4) | 0.026 (9)* | |
H11 | 0.280 (1) | 1.403 (4) | 0.313 (4) | 0.04 (1)* | |
H12 | 0.287 (1) | 1.410 (4) | 0.123 (4) | 0.03 (1)* | |
H14 | 0.2035 | 1.1022 | 0.0655 | 0.0317* | |
H15 | 0.200 (1) | 1.118 (4) | 0.256 (4) | 0.04 (1)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Ni1 | 0.0164 (2) | 0.0154 (3) | 0.0160 (2) | −0.0004 (2) | 0.0067 (2) | −0.0007 (2) |
Ni2 | 0.0172 (2) | 0.0232 (3) | 0.0182 (3) | 0.0050 (2) | 0.0033 (2) | 0.0012 (2) |
V1 | 0.0189 (2) | 0.0207 (3) | 0.0148 (2) | −0.0002 (2) | 0.0045 (2) | 0.0028 (2) |
V2 | 0.0169 (2) | 0.0251 (3) | 0.0143 (2) | −0.0003 (2) | 0.0045 (2) | −0.0021 (2) |
O1 | 0.0224 (9) | 0.025 (1) | 0.0194 (10) | −0.0048 (8) | 0.0083 (8) | −0.0007 (9) |
O2 | 0.047 (1) | 0.048 (2) | 0.035 (1) | 0.022 (1) | 0.003 (1) | 0.003 (1) |
O3 | 0.029 (1) | 0.052 (2) | 0.028 (1) | −0.003 (1) | 0.0088 (10) | 0.011 (1) |
O4 | 0.023 (1) | 0.042 (2) | 0.031 (1) | 0.002 (1) | 0.0041 (9) | −0.008 (1) |
O5 | 0.038 (1) | 0.037 (2) | 0.029 (1) | −0.004 (1) | 0.022 (1) | −0.001 (1) |
O6 | 0.065 (2) | 0.026 (2) | 0.043 (2) | −0.014 (1) | 0.026 (1) | −0.005 (1) |
O7 | 0.032 (1) | 0.053 (2) | 0.026 (1) | 0.012 (1) | 0.0032 (10) | 0.018 (1) |
N1 | 0.021 (1) | 0.018 (1) | 0.022 (1) | 0.0025 (9) | 0.0086 (9) | −0.0001 (10) |
N2 | 0.022 (1) | 0.021 (1) | 0.016 (1) | −0.0006 (10) | 0.0087 (8) | −0.0012 (10) |
N3 | 0.024 (1) | 0.023 (2) | 0.023 (1) | 0.005 (1) | 0.0062 (10) | 0.001 (1) |
C1 | 0.032 (2) | 0.025 (2) | 0.032 (2) | 0.009 (1) | 0.017 (1) | 0.009 (1) |
C2 | 0.032 (2) | 0.028 (2) | 0.033 (2) | 0.010 (1) | 0.022 (1) | 0.008 (1) |
C3 | 0.025 (1) | 0.021 (2) | 0.024 (1) | 0.005 (1) | 0.009 (1) | 0.001 (1) |
C4 | 0.036 (2) | 0.024 (2) | 0.029 (2) | 0.010 (1) | 0.017 (1) | 0.009 (1) |
C5 | 0.030 (1) | 0.025 (2) | 0.029 (2) | 0.008 (1) | 0.018 (1) | 0.006 (1) |
C6 | 0.026 (1) | 0.023 (2) | 0.025 (1) | 0.007 (1) | 0.011 (1) | 0.003 (1) |
C7 | 0.031 (1) | 0.029 (2) | 0.023 (2) | 0.012 (1) | 0.004 (1) | 0.002 (1) |
C8 | 0.035 (2) | 0.028 (2) | 0.018 (1) | 0.011 (1) | 0.006 (1) | −0.001 (1) |
C9 | 0.041 (2) | 0.047 (3) | 0.023 (2) | 0.025 (2) | 0.008 (1) | 0.009 (2) |
C10 | 0.048 (2) | 0.048 (3) | 0.021 (2) | 0.023 (2) | 0.015 (1) | 0.004 (2) |
C11 | 0.025 (1) | 0.022 (2) | 0.016 (1) | −0.004 (1) | 0.005 (1) | −0.002 (1) |
C12 | 0.025 (1) | 0.026 (2) | 0.018 (1) | −0.010 (1) | 0.006 (1) | 0.000 (1) |
C13 | 0.024 (1) | 0.023 (2) | 0.013 (1) | −0.002 (1) | 0.0077 (10) | −0.002 (1) |
C14 | 0.044 (2) | 0.030 (2) | 0.025 (2) | −0.020 (2) | 0.019 (1) | −0.011 (1) |
C15 | 0.040 (2) | 0.028 (2) | 0.022 (1) | −0.014 (1) | 0.016 (1) | −0.007 (1) |
Ni1—O1i | 2.017 (2) | C1—C2 | 1.383 (5) |
Ni1—O1ii | 2.017 (2) | C2—C3 | 1.380 (5) |
Ni1—N1 | 2.162 (3) | C3—C4 | 1.403 (5) |
Ni1—N1iii | 2.162 (3) | C3—C6 | 1.485 (4) |
Ni1—N2 | 2.231 (2) | C4—C5 | 1.375 (5) |
Ni1—N2iii | 2.231 (2) | C6—C10 | 1.385 (5) |
Ni2—O4 | 2.034 (2) | C6—C7 | 1.385 (5) |
Ni2—O4iv | 2.034 (2) | C7—C8 | 1.384 (5) |
Ni2—N3 | 2.099 (3) | C9—C10 | 1.382 (5) |
Ni2—N3iv | 2.099 (3) | C11—C12 | 1.382 (4) |
Ni2—O3 | 2.103 (3) | C12—C13 | 1.390 (4) |
Ni2—O3iv | 2.103 (3) | C13—C14 | 1.378 (4) |
V1—O6 | 1.612 (3) | C13—C13vi | 1.496 (6) |
V1—O4 | 1.663 (2) | C14—C15 | 1.393 (4) |
V1—O7 | 1.788 (2) | C1—H1 | 1.01 (4) |
V1—O5 | 1.791 (3) | C2—H2 | 0.81 (5) |
V2—O2 | 1.615 (3) | C4—H3 | 0.97 (5) |
V2—O1 | 1.661 (2) | C5—H4 | 1.02 (4) |
V2—O7v | 1.781 (3) | C7—H7 | 0.99 (4) |
V2—O5 | 1.793 (3) | C8—H8 | 0.98 (5) |
N1—C1 | 1.329 (4) | C9—H9 | 0.92 (4) |
N1—C5 | 1.344 (4) | C10—H10 | 0.85 (4) |
N2—C11 | 1.342 (4) | C11—H11 | 0.93 (4) |
N2—C15 | 1.347 (4) | C12—H12 | 0.98 (4) |
N3—C9 | 1.332 (5) | C14—H14 | 1.023 |
N3—C8 | 1.340 (4) | C15—H15 | 1.04 (5) |
O2···O8 | 2.72 (1) | O9···O10viii | 2.13 (3) |
O3···O8 | 2.78 (1) | O9···O9viii | 2.68 (4) |
O8···O9 | 2.15 (2) | O9···O10 | 3.03 (3) |
O8···O10 | 2.37 (3) | O9···O10ix | 3.27 (3) |
O8···O10vii | 3.07 (3) | O10···O10vii | 1.28 (4) |
O1i—Ni1—O1ii | 180.0 | O4—V1—O7 | 111.6 (1) |
O1i—Ni1—N1 | 90.27 (10) | O4—V1—O5 | 110.7 (1) |
O1i—Ni1—N1iii | 89.73 (10) | O7—V1—O5 | 108.8 (1) |
O1i—Ni1—N2 | 89.41 (9) | O2—V2—O1 | 110.9 (1) |
O1i—Ni1—N2iii | 90.59 (9) | O2—V2—O7v | 109.8 (1) |
O1ii—Ni1—N1 | 89.73 (10) | O2—V2—O5 | 109.4 (1) |
O1ii—Ni1—N1iii | 90.27 (10) | O1—V2—O7v | 109.0 (1) |
O1ii—Ni1—N2 | 90.59 (9) | O1—V2—O5 | 108.7 (1) |
O1ii—Ni1—N2iii | 89.41 (9) | O7v—V2—O5 | 109.0 (1) |
N1—Ni1—N1iii | 180.0 | C1—N1—C5 | 116.7 (3) |
N1—Ni1—N2 | 87.66 (10) | C11—N2—C15 | 115.6 (3) |
N1—Ni1—N2iii | 92.34 (10) | C9—N3—C8 | 116.4 (3) |
N1iii—Ni1—N2 | 92.34 (10) | N1—C1—C2 | 123.5 (3) |
N1iii—Ni1—N2iii | 87.66 (10) | C3—C2—C1 | 120.1 (3) |
N2—Ni1—N2iii | 180.0 | C2—C3—C4 | 116.7 (3) |
O4—Ni2—O4iv | 180.0 | C2—C3—C6 | 122.1 (3) |
O4—Ni2—N3 | 88.9 (1) | C4—C3—C6 | 121.2 (3) |
O4—Ni2—N3iv | 91.1 (1) | C5—C4—C3 | 119.3 (3) |
O4—Ni2—O3 | 91.2 (1) | N1—C5—C4 | 123.7 (3) |
O4—Ni2—O3iv | 88.8 (1) | C10—C6—C7 | 117.1 (3) |
O4iv—Ni2—N3 | 91.1 (1) | C10—C6—C3 | 120.4 (3) |
O4iv—Ni2—N3iv | 88.9 (1) | C7—C6—C3 | 122.4 (3) |
O4iv—Ni2—O3 | 88.8 (1) | C8—C7—C6 | 119.3 (3) |
O4iv—Ni2—O3iv | 91.2 (1) | N3—C8—C7 | 123.7 (3) |
N3—Ni2—N3iv | 180.0 | N3—C9—C10 | 123.7 (3) |
N3—Ni2—O3 | 91.2 (1) | C9—C10—C6 | 119.7 (3) |
N3—Ni2—O3iv | 88.8 (1) | N2—C11—C12 | 124.4 (3) |
N3iv—Ni2—O3 | 88.8 (1) | C11—C12—C13 | 120.0 (3) |
N3iv—Ni2—O3iv | 91.2 (1) | C14—C13—C12 | 115.8 (3) |
O3—Ni2—O3iv | 180.0 | C14—C13—C13vi | 122.5 (3) |
O6—V1—O4 | 109.0 (2) | C12—C13—C13vi | 121.7 (4) |
O6—V1—O7 | 108.1 (1) | C13—C14—C15 | 121.3 (3) |
O6—V1—O5 | 108.6 (1) | N2—C15—C14 | 122.8 (3) |
Symmetry codes: (i) x, y+1, z; (ii) −x+1/2, −y+3/2, −z+1; (iii) −x+1/2, −y+5/2, −z+1; (iv) −x+1, −y+1, −z+1; (v) x, −y+1, z+1/2; (vi) −x+1/2, −y+5/2, −z; (vii) −x+1, y, −z+3/2; (viii) −x+1, −y, −z+1; (ix) x, −y, z−1/2. |
Experimental details
Crystal data | |
Chemical formula | [Ni2(V2O6)2(C10H8N2)3(H2O)2]·2.5H2O |
Mr | 1062.79 |
Crystal system, space group | Monoclinic, C2/c |
Temperature (K) | 173 |
a, b, c (Å) | 30.3799 (9), 11.2402 (3), 11.5366 (3) |
β (°) | 105.961 (1) |
V (Å3) | 3787.6 (2) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 2.00 |
Crystal size (mm) | 0.30 × 0.12 × 0.03 |
Data collection | |
Diffractometer | Rigaku RAXIS-RAPID Imaging Plate diffractometer |
Absorption correction | Multi-scan (Higashi, 1995) |
Tmin, Tmax | 0.515, 0.869 |
No. of measured, independent and observed [F2 > 2.0σ(F2)] reflections | 14250, 5509, 4198 |
Rint | 0.027 |
(sin θ/λ)max (Å−1) | 0.703 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.042, 0.114, 1.40 |
No. of reflections | 4634 |
No. of parameters | 312 |
No. of restraints | ? |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.90, −0.50 |
Computer programs: PROCESS-AUTO (Rigaku Corporation, 1998), PROCESS-AUTO, TEXSAN (Molecular Structure Corporation, 1985, 1989), SIR92 (Altomare et al., 1994), TEXSAN.
Ni1—O1i | 2.017 (2) | Ni2—O3 | 2.103 (3) |
Ni1—O1ii | 2.017 (2) | Ni2—O3iv | 2.103 (3) |
Ni1—N1 | 2.162 (3) | V1—O6 | 1.612 (3) |
Ni1—N1iii | 2.162 (3) | V1—O4 | 1.663 (2) |
Ni1—N2 | 2.231 (2) | V1—O7 | 1.788 (2) |
Ni1—N2iii | 2.231 (2) | V1—O5 | 1.791 (3) |
Ni2—O4 | 2.034 (2) | V2—O2 | 1.615 (3) |
Ni2—O4iv | 2.034 (2) | V2—O1 | 1.661 (2) |
Ni2—N3 | 2.099 (3) | V2—O7v | 1.781 (3) |
Ni2—N3iv | 2.099 (3) | V2—O5 | 1.793 (3) |
Symmetry codes: (i) x, y+1, z; (ii) −x+1/2, −y+3/2, −z+1; (iii) −x+1/2, −y+5/2, −z+1; (iv) −x+1, −y+1, −z+1; (v) x, −y+1, z+1/2. |
There is an increasing interest in the synthesis of organic/inorganic hybrid compounds because of their novel structural architectures (Hagrman et al., 1999) and unusual electrochemical (Leroux et al., 1996) and magnetic (Lira-Cantú & Gómez-Romero, 1998) properties. Hydrothermal synthesis and structural characterization of vanadium oxide lattices containing Zn-, Cu-, and Co-bipyridyl (bipy) complexes has been intensively studied because of their large structural diversity: for example, two-dimensional layered vanadium oxide with interlayer zinc 2,2'-bipy complex, [Zn(2,2'-bipy)2]2V6O17 (Zhang et al., 1996), discrete neutral hexanuclear [Zn2V4] clusters, [{Zn(2,2'-bipy)2}2V4O12] (Zhang et al., 1997), one-dimensional vanadium oxide chain with copper 2,2'-bipy complexes, [Cu(2,2'-bipy)V2O6] and [Cu(2,2'-bipy)2V2O6] (DeBord et al., 1996) and three-dimensional bimetallic oxide network, [{Co(3,3'-bipy)2}2V4O12] (LaDuca et al., 2000). It should be noted that all the bipy ligands in these complexes are of 2,2'- and 3,3'-isomers, and no 4,4'-bipy containing compound has been observed in the vanadate/M(bipy)n system. Here we report the synthesis and crystal structure of [Ni2(4,4'-bipy)3(H2O)2V4O12]·2.5H2O, (I), which is constructed from a three-dimensional network containing {V2O6}∞ and Ni/V-bimetallic oxide chains linked by 4,4'-bipy ligands.
Fig. 1 shows the structure of [Ni2(4,4'-bipy)3(H2O)2V4O12]·2.5H2O, which consists of [Ni1(4,4'-bipy)4O2], [V2O6], [Ni2(H2O)2(4,4'-bipy)2O2] units, and crystallization water molecules of O8, O9 and O10. The [V2O6] unit is made up of a pair of corner-sharing [VO4] tetrahedra. There are three types of oxygen atoms in the [V2O6] group: terminal O2 and O6 atoms; bridging O5 and O7 atoms connected to both V1 and V2 atoms; bridging O1 and O4 atoms linking Ni and V atoms. Table 1 lists the selected bond distances. Ni1 is coordinated by O1i and O1ii atoms from two [V2O6] groups, N1, N1iii, N2 and N2iii atoms [Ni—N 2.162 (3)–2.233 (3) Å] from four 4,4'-bipy ligands to form an Ni1O2N4 octahedron, while Ni2 is coordinated by O4 and O4iv atoms from two [V2O6] groups, N3 and N3iv atoms from two 4,4'-bipy ligands, and O3 and O3iv atoms identified as water molecules from the Ni2—O3 bond valence of 0.29 (Brown & Altermatt, 1985; Brese & O'Keeffe, 1991) to form an Ni2O4N4 octahedron. O(N)—Ni—O(N) bond angles in the Ni1O2N4 and Ni2O4N2octahedra are nearly 90° [88.7 (1)–91.3 (1)°] or ideally linear (180°). The [V2O6] group links Ni1vi and Ni2 atoms, forming a -[Ni2(H2O)2(4,4'-bipy)2]-[V2O6]- [Ni1(4,4'-bipy)4]- bimetallic chain. Two crystallographically different 4,4'-bipy groups are present: 4,4'-bipy(I) comprises N1, N3, C1–C10 atoms, and 4,4'-bipy(II) comprises N2, C11–C15 and their symmetry-related atoms. In the 4,4'-bipy(I) group, the dihedral angle between the two pyridyl rings of N1,C1–C5 and N3,C6–C10 is 35.8 (1)°. This is in contrast to the conformation between the two rings in the 4,4'-bipy(II) group which are constrained to be planar by a centre of symmetry. The 4,4'-bipy(I) links Ni1 and Ni2 atoms in two adjacent bimetallic chains, to give a two-dimensional infinite network sheet parallel to the ab plane (Fig. 1). Fig. 2 shows the crystal structure of [Ni2(4,4'-bipy)3(H2O)2V4O12]·2.5H2O viewed down the b axis. There exist two crystallographically equivalent two-dimensional network sheets, denoted by sheet A and sheet B in Fig. 2, which are stacked alternately (···ABAB···) along the c axis with an interval of 5.53 Å. Each of the 4,4'-bipy(II) groups lying in the c direction links two Ni1 atoms in two different sheets A, or equivalently sheets B. Also, the [V2O6] groups in two adjacent sheets A and B are connected through the O7 atom, to form an infinite [V2O6]∞ chain running along the c axis.
In conclusion, it is the characteristic geometry of 4,4'-bipy, where N donors are located in two opposite ends of the ligand, that leads to the highly interlinked three-dimensional network structure. The successful preparation of the new three-dimensional network vanadium oxide cluster with a nickel complex of 4,4'-bipy ligand will extend the variety of network structures in the organic/inorganic hybrid system.