Acta Cryst. (2009). E65, m1302-m1303 [ doi:10.1107/S1600536809039786 ]
![[mu]](/logos/entities/mu_rmgif.gif)
2-4,4'-bipyridine)bis(3-nitrobenzoato)cobalt(II)]The hydrothermal reaction of cobalt nitrate with 4,4'-bipyridine and 3-nitrobenzoic acid lead to the formation of the title complex, [Co(C7H4NO4)2(C10H8N2)2]n. In the crystal structure, the CoII atoms are coordinated by two terminal carboxylate anions and four 4,4'-bipyridine ligands within slightly distorted octahedra. The CoII atom and one of the two independent 4,4'-bipyridine ligands are located on a twofold rotation axis, while the second independent 4,4'-bipyridine molecule is located on a centre of inversion. One of the two rings of one 4,4'-bipyridine ligand is disordered over two orientations and was refined using a split model [occupancy ratio 0.68 (2):0.32 (2)]. The CoII atoms are connected by the 4,4'-bipyridine ligands into layers, which are located parallel to the ab plane.
The title compound was prepared by the reaction of 4,4'-bipyridine (0.0781 g, 0.5 mmol), 3-nitrobenzoic acid (0.0836 g, 0.5 mmol), Co(NO3)2.6H2O (0.1454 g, 0.5 mmol), H2O (12.0 ml) and NH4OH (0.1 ml) at a pH value of 9.28. The mixture was heated to 423 K for 2 days in a Teflon-lined autoclave with an internal volume of 23 ml followed by slow cooling at 6 K/h to room temperature. The title compound was obtained as orange crystals with a yield of 0.0284 g (7.7%, based on cobalt). Anal. found/calcd.: C, 58.11/58.06; N, 12.14/11.95; H, 3.46/3.44%.
The hydrogen atoms of benzene rings are placed in idealized positions and constrained to ride on their parent atoms, with C—H = 0.93 Å and Uiso(H) = 1.2 Ueq(C). The C12 and C13 atoms are disordered and were refined using a split model with occupancies of 0.68 (2) and 0.32 (2).
Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).
![[Figure 1]](./nc2159fig1thm.gif)
| Fig. 1. Crystal structure of the title compound with labeling and displacement ellipsoids drawn at the 50% probability level. [symmetry codes: (i) -x + 1,y,-z + 5/2; (ii) x,y - 1,z; (iii) -x + 1,y + 1,-z + 5/2; (iv) -x + 1/2,-y + 5/2,-z + 2.]. The H atoms are omitted for clarity. |
![[Figure 2]](./nc2159fig2thm.gif)
| Fig. 2. Crystal structure of the title compound in c-direction showing the layers. The H atoms and the disordered C atoms are not shown for clarity. |
| [Co(C7H4NO4)2(C10H8N2)2] | F(000) = 1444 |
| Mr = 703.52 | Dx = 1.491 Mg m−3 |
| Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
| Hall symbol: -C 2yc | Cell parameters from 6091 reflections |
| a = 18.2074 (15) Å | θ = 2.3–28.1° |
| b = 11.4717 (8) Å | µ = 0.61 mm−1 |
| c = 15.0543 (12) Å | T = 295 K |
| β = 94.661 (2)° | Columnar, pink |
| V = 3134.0 (4) Å3 | 0.40 × 0.25 × 0.15 mm |
| Z = 4 |
| Bruker APEXII CCD diffractometer | 3861 independent reflections |
| Radiation source: fine-focus sealed tube | 3389 reflections with I > 2σ(I) |
| graphite | Rint = 0.023 |
| Detector resolution: 8.3333 pixels mm-1 | θmax = 28.3°, θmin = 2.1° |
| φ and ω scans | h = −24→23 |
| Absorption correction: multi-scan (SADABS; Bruker, 2008) | k = −8→15 |
| Tmin = 0.792, Tmax = 0.914 | l = −19→20 |
| 13056 measured reflections |
| 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)] = 0.030 | Hydrogen site location: inferred from neighbouring sites |
| wR(F2) = 0.085 | H-atom parameters constrained |
| S = 1.03 | w = 1/[σ2(Fo2) + (0.0451P)2 + 1.8393P] where P = (Fo2 + 2Fc2)/3 |
| 3861 reflections | (Δ/σ)max = 0.002 |
| 243 parameters | Δρmax = 0.29 e Å−3 |
| 0 restraints | Δρmin = −0.25 e Å−3 |
| [Co(C7H4NO4)2(C10H8N2)2] | V = 3134.0 (4) Å3 |
| Mr = 703.52 | Z = 4 |
| Monoclinic, C2/c | Mo Kα radiation |
| a = 18.2074 (15) Å | µ = 0.61 mm−1 |
| b = 11.4717 (8) Å | T = 295 K |
| c = 15.0543 (12) Å | 0.40 × 0.25 × 0.15 mm |
| β = 94.661 (2)° |
| Bruker APEXII CCD diffractometer | 3861 independent reflections |
| Absorption correction: multi-scan (SADABS; Bruker, 2008) | 3389 reflections with I > 2σ(I) |
| Tmin = 0.792, Tmax = 0.914 | Rint = 0.023 |
| 13056 measured reflections | θmax = 28.3° |
| R[F2 > 2σ(F2)] = 0.030 | H-atom parameters constrained |
| wR(F2) = 0.085 | Δρmax = 0.29 e Å−3 |
| S = 1.03 | Δρmin = −0.25 e Å−3 |
| 3861 reflections | Absolute structure: ? |
| 243 parameters | Flack parameter: ? |
| 0 restraints | Rogers parameter: ? |
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) | |
| Co1 | 0.5000 | 1.191582 (19) | 1.2500 | 0.02382 (8) | |
| O1 | 0.57262 (6) | 1.18588 (9) | 1.15246 (7) | 0.0354 (2) | |
| O2 | 0.55038 (8) | 1.25715 (13) | 1.01478 (8) | 0.0558 (3) | |
| O3 | 0.81068 (14) | 1.0206 (2) | 0.83179 (16) | 0.1227 (9) | |
| O4 | 0.70904 (15) | 1.1028 (2) | 0.79153 (13) | 0.1102 (8) | |
| N1 | 0.5000 | 1.38167 (14) | 1.2500 | 0.0311 (3) | |
| N2 | 0.5000 | 0.99916 (13) | 1.2500 | 0.0300 (3) | |
| N3 | 0.40427 (7) | 1.19830 (9) | 1.15518 (8) | 0.0298 (2) | |
| N4 | 0.75458 (14) | 1.06877 (18) | 0.84869 (16) | 0.0765 (6) | |
| C1 | 0.58770 (8) | 1.20319 (12) | 1.07270 (10) | 0.0330 (3) | |
| C2 | 0.66071 (9) | 1.15062 (13) | 1.05012 (10) | 0.0347 (3) | |
| C3 | 0.67493 (10) | 1.13700 (14) | 0.96153 (11) | 0.0427 (4) | |
| H3A | 0.6406 | 1.1601 | 0.9158 | 0.051* | |
| C4 | 0.74128 (12) | 1.08841 (15) | 0.94287 (13) | 0.0517 (5) | |
| C5 | 0.79520 (11) | 1.05707 (17) | 1.00796 (16) | 0.0590 (5) | |
| H5A | 0.8399 | 1.0267 | 0.9930 | 0.071* | |
| C6 | 0.78115 (11) | 1.07189 (17) | 1.09553 (15) | 0.0548 (5) | |
| H6A | 0.8169 | 1.0522 | 1.1407 | 0.066* | |
| C7 | 0.71369 (9) | 1.11618 (14) | 1.11679 (12) | 0.0435 (4) | |
| H7A | 0.7039 | 1.1229 | 1.1762 | 0.052* | |
| C8 | 0.49826 (9) | 1.44210 (12) | 1.17370 (10) | 0.0359 (3) | |
| H8A | 0.4975 | 1.4011 | 1.1203 | 0.043* | |
| C9 | 0.49748 (9) | 1.56253 (12) | 1.17056 (10) | 0.0370 (3) | |
| H9A | 0.4953 | 1.6012 | 1.1161 | 0.044* | |
| C10 | 0.5000 | 1.62512 (16) | 1.2500 | 0.0317 (4) | |
| C11 | 0.5000 | 1.75431 (16) | 1.2500 | 0.0314 (4) | |
| C12 | 0.5282 (4) | 0.9374 (4) | 1.1858 (3) | 0.0383 (11) | 0.68 (2) |
| H12 | 0.5490 | 0.9779 | 1.1406 | 0.046* | 0.68 (2) |
| C13 | 0.5285 (4) | 0.8176 (4) | 1.1825 (3) | 0.0402 (11) | 0.68 (2) |
| H13 | 0.5477 | 0.7793 | 1.1351 | 0.048* | 0.68 (2) |
| C12' | 0.5517 (9) | 0.9382 (10) | 1.2151 (18) | 0.060 (4) | 0.32 (2) |
| H12' | 0.5890 | 0.9784 | 1.1896 | 0.071* | 0.32 (2) |
| C13' | 0.5538 (10) | 0.8169 (9) | 1.2143 (19) | 0.068 (5) | 0.32 (2) |
| H13' | 0.5920 | 0.7785 | 1.1892 | 0.082* | 0.32 (2) |
| C14 | 0.40078 (8) | 1.15400 (14) | 1.07344 (10) | 0.0362 (3) | |
| H14A | 0.4399 | 1.1087 | 1.0574 | 0.043* | |
| C15 | 0.34177 (8) | 1.17185 (14) | 1.01086 (10) | 0.0369 (3) | |
| H15A | 0.3422 | 1.1395 | 0.9543 | 0.044* | |
| C16 | 0.28195 (7) | 1.23815 (12) | 1.03276 (9) | 0.0281 (3) | |
| C17 | 0.28502 (9) | 1.28120 (15) | 1.11918 (10) | 0.0386 (3) | |
| H17A | 0.2458 | 1.3239 | 1.1381 | 0.046* | |
| C18 | 0.34630 (9) | 1.26053 (15) | 1.17697 (10) | 0.0381 (3) | |
| H18A | 0.3474 | 1.2915 | 1.2341 | 0.046* |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| Co1 | 0.02889 (14) | 0.01737 (12) | 0.02410 (13) | 0.000 | −0.00451 (9) | 0.000 |
| O1 | 0.0408 (6) | 0.0355 (5) | 0.0300 (5) | −0.0014 (4) | 0.0041 (4) | 0.0005 (4) |
| O2 | 0.0581 (8) | 0.0690 (9) | 0.0398 (7) | 0.0156 (7) | 0.0004 (6) | 0.0141 (6) |
| O3 | 0.1288 (19) | 0.144 (2) | 0.1065 (16) | 0.0236 (16) | 0.0775 (15) | −0.0159 (14) |
| O4 | 0.137 (2) | 0.150 (2) | 0.0493 (10) | 0.0023 (16) | 0.0364 (12) | −0.0075 (12) |
| N1 | 0.0420 (9) | 0.0187 (7) | 0.0316 (8) | 0.000 | −0.0024 (7) | 0.000 |
| N2 | 0.0347 (8) | 0.0192 (7) | 0.0354 (9) | 0.000 | −0.0011 (7) | 0.000 |
| N3 | 0.0314 (6) | 0.0275 (6) | 0.0293 (6) | 0.0021 (4) | −0.0044 (5) | −0.0009 (4) |
| N4 | 0.0978 (16) | 0.0672 (12) | 0.0717 (13) | −0.0167 (11) | 0.0522 (13) | −0.0103 (10) |
| C1 | 0.0392 (7) | 0.0287 (7) | 0.0307 (7) | −0.0045 (6) | 0.0006 (6) | 0.0000 (5) |
| C2 | 0.0435 (8) | 0.0259 (6) | 0.0352 (7) | −0.0049 (6) | 0.0064 (6) | 0.0022 (6) |
| C3 | 0.0555 (10) | 0.0350 (8) | 0.0389 (8) | −0.0080 (7) | 0.0121 (7) | 0.0018 (6) |
| C4 | 0.0668 (12) | 0.0365 (8) | 0.0559 (11) | −0.0120 (8) | 0.0305 (9) | −0.0021 (7) |
| C5 | 0.0527 (11) | 0.0418 (9) | 0.0863 (15) | 0.0012 (8) | 0.0290 (11) | 0.0038 (10) |
| C6 | 0.0469 (10) | 0.0475 (10) | 0.0699 (13) | 0.0050 (8) | 0.0040 (9) | 0.0080 (9) |
| C7 | 0.0486 (9) | 0.0386 (8) | 0.0434 (9) | 0.0020 (7) | 0.0042 (7) | 0.0044 (7) |
| C8 | 0.0541 (9) | 0.0223 (6) | 0.0304 (7) | 0.0012 (6) | −0.0016 (6) | −0.0023 (5) |
| C9 | 0.0573 (9) | 0.0219 (6) | 0.0315 (7) | 0.0014 (6) | 0.0009 (6) | 0.0038 (5) |
| C10 | 0.0404 (10) | 0.0184 (8) | 0.0361 (10) | 0.000 | 0.0026 (8) | 0.000 |
| C11 | 0.0418 (10) | 0.0178 (8) | 0.0342 (10) | 0.000 | 0.0010 (8) | 0.000 |
| C12 | 0.058 (3) | 0.0214 (12) | 0.0374 (18) | −0.0007 (16) | 0.0131 (15) | 0.0017 (11) |
| C13 | 0.063 (3) | 0.0222 (13) | 0.0373 (18) | 0.0007 (16) | 0.0180 (15) | −0.0022 (11) |
| C12' | 0.052 (6) | 0.024 (3) | 0.107 (12) | −0.001 (4) | 0.035 (7) | 0.009 (6) |
| C13' | 0.062 (7) | 0.024 (3) | 0.126 (14) | 0.012 (4) | 0.050 (8) | 0.008 (6) |
| C14 | 0.0291 (7) | 0.0399 (8) | 0.0382 (8) | 0.0062 (6) | −0.0050 (6) | −0.0108 (6) |
| C15 | 0.0316 (7) | 0.0464 (8) | 0.0315 (7) | 0.0052 (6) | −0.0048 (6) | −0.0132 (6) |
| C16 | 0.0278 (6) | 0.0288 (6) | 0.0270 (6) | 0.0008 (5) | −0.0028 (5) | 0.0014 (5) |
| C17 | 0.0379 (8) | 0.0490 (9) | 0.0281 (7) | 0.0165 (7) | −0.0030 (6) | −0.0023 (6) |
| C18 | 0.0414 (8) | 0.0461 (8) | 0.0254 (7) | 0.0123 (7) | −0.0055 (6) | −0.0040 (6) |
| Co1—O1 | 2.0553 (11) | C7—H7A | 0.9300 |
| Co1—O1i | 2.0553 (11) | C8—C9 | 1.3824 (19) |
| Co1—N3 | 2.1627 (12) | C8—H8A | 0.9300 |
| Co1—N3i | 2.1627 (12) | C9—C10 | 1.3925 (17) |
| Co1—N1 | 2.1807 (16) | C9—H9A | 0.9300 |
| Co1—N2 | 2.2074 (16) | C10—C9i | 1.3925 (17) |
| O1—C1 | 1.2689 (18) | C10—C11 | 1.482 (3) |
| O2—C1 | 1.2283 (19) | C11—C13'ii | 1.359 (12) |
| O3—N4 | 1.206 (3) | C11—C13'iii | 1.359 (11) |
| O4—N4 | 1.210 (3) | C11—C13iii | 1.384 (5) |
| N1—C8 | 1.3398 (16) | C11—C13ii | 1.384 (5) |
| N1—C8i | 1.3398 (16) | C12—C13 | 1.375 (7) |
| N2—C12' | 1.315 (12) | C12—H12 | 0.9300 |
| N2—C12'i | 1.315 (12) | C13—C11iv | 1.384 (5) |
| N2—C12i | 1.334 (5) | C13—H13 | 0.9300 |
| N2—C12 | 1.334 (5) | C12'—C13' | 1.392 (16) |
| N3—C14 | 1.3280 (18) | C12'—H12' | 0.9300 |
| N3—C18 | 1.3370 (19) | C13'—C11iv | 1.359 (11) |
| N4—C4 | 1.475 (3) | C13'—H13' | 0.9300 |
| C1—C2 | 1.523 (2) | C14—C15 | 1.385 (2) |
| C2—C3 | 1.388 (2) | C14—H14A | 0.9300 |
| C2—C7 | 1.392 (2) | C15—C16 | 1.390 (2) |
| C3—C4 | 1.380 (3) | C15—H15A | 0.9300 |
| C3—H3A | 0.9300 | C16—C17 | 1.388 (2) |
| C4—C5 | 1.377 (3) | C16—C16v | 1.488 (2) |
| C5—C6 | 1.374 (3) | C17—C18 | 1.379 (2) |
| C5—H5A | 0.9300 | C17—H17A | 0.9300 |
| C6—C7 | 1.390 (2) | C18—H18A | 0.9300 |
| C6—H6A | 0.9300 | ||
| O1—Co1—O1i | 176.35 (6) | C5—C6—H6A | 119.9 |
| O1—Co1—N3 | 93.46 (5) | C7—C6—H6A | 119.9 |
| O1i—Co1—N3 | 86.68 (5) | C2—C7—C6 | 120.74 (17) |
| O1—Co1—N3i | 86.67 (5) | C2—C7—H7A | 119.6 |
| O1i—Co1—N3i | 93.46 (5) | C6—C7—H7A | 119.6 |
| N3—Co1—N3i | 175.92 (6) | N1—C8—C9 | 123.08 (14) |
| O1—Co1—N1 | 91.82 (3) | N1—C8—H8A | 118.5 |
| O1i—Co1—N1 | 91.82 (3) | C9—C8—H8A | 118.5 |
| N3—Co1—N1 | 87.96 (3) | C8—C9—C10 | 119.11 (14) |
| N3i—Co1—N1 | 87.96 (3) | C8—C9—H9A | 120.4 |
| O1—Co1—N2 | 88.18 (3) | C10—C9—H9A | 120.4 |
| O1i—Co1—N2 | 88.18 (3) | C9—C10—C9i | 117.92 (17) |
| N3—Co1—N2 | 92.04 (3) | C9—C10—C11 | 121.04 (9) |
| N3i—Co1—N2 | 92.04 (3) | C9i—C10—C11 | 121.04 (9) |
| N1—Co1—N2 | 180.000 (1) | C13'ii—C11—C13'iii | 116.3 (9) |
| C1—O1—Co1 | 150.73 (10) | C13'ii—C11—C13iii | 109.8 (6) |
| C8—N1—C8i | 117.69 (17) | C13'iii—C11—C13ii | 109.8 (6) |
| C8—N1—Co1 | 121.16 (8) | C13iii—C11—C13ii | 116.7 (4) |
| C8i—N1—Co1 | 121.16 (8) | C13'ii—C11—C10 | 121.9 (4) |
| C12'—N2—C12'i | 115.7 (10) | C13'iii—C11—C10 | 121.9 (5) |
| C12'—N2—C12i | 109.7 (5) | C13iii—C11—C10 | 121.7 (2) |
| C12'i—N2—C12 | 109.7 (5) | C13ii—C11—C10 | 121.7 (2) |
| C12i—N2—C12 | 115.9 (4) | N2—C12—C13 | 124.0 (4) |
| C12'—N2—Co1 | 122.1 (5) | N2—C12—H12 | 118.0 |
| C12'i—N2—Co1 | 122.1 (5) | C13—C12—H12 | 118.0 |
| C12i—N2—Co1 | 122.1 (2) | C12—C13—C11iv | 119.7 (4) |
| C12—N2—Co1 | 122.1 (2) | C12—C13—H13 | 120.2 |
| C14—N3—C18 | 116.89 (12) | C11iv—C13—H13 | 120.2 |
| C14—N3—Co1 | 124.98 (10) | N2—C12'—C13' | 123.8 (10) |
| C18—N3—Co1 | 117.84 (9) | N2—C12'—H12' | 118.1 |
| O3—N4—O4 | 122.7 (2) | C13'—C12'—H12' | 118.1 |
| O3—N4—C4 | 118.7 (3) | C11iv—C13'—C12' | 120.2 (9) |
| O4—N4—C4 | 118.5 (2) | C11iv—C13'—H13' | 119.9 |
| O2—C1—O1 | 126.93 (15) | C12'—C13'—H13' | 119.9 |
| O2—C1—C2 | 118.91 (14) | N3—C14—C15 | 123.34 (13) |
| O1—C1—C2 | 114.15 (13) | N3—C14—H14A | 118.3 |
| C3—C2—C7 | 119.26 (15) | C15—C14—H14A | 118.3 |
| C3—C2—C1 | 119.56 (14) | C14—C15—C16 | 119.93 (13) |
| C7—C2—C1 | 121.18 (14) | C14—C15—H15A | 120.0 |
| C4—C3—C2 | 118.41 (17) | C16—C15—H15A | 120.0 |
| C4—C3—H3A | 120.8 | C17—C16—C15 | 116.37 (12) |
| C2—C3—H3A | 120.8 | C17—C16—C16v | 121.74 (15) |
| C3—C4—C5 | 123.09 (18) | C15—C16—C16v | 121.89 (16) |
| C3—C4—N4 | 118.2 (2) | C18—C17—C16 | 119.94 (13) |
| C5—C4—N4 | 118.7 (2) | C18—C17—H17A | 120.0 |
| C6—C5—C4 | 118.21 (18) | C16—C17—H17A | 120.0 |
| C6—C5—H5A | 120.9 | N3—C18—C17 | 123.48 (14) |
| C4—C5—H5A | 120.9 | N3—C18—H18A | 118.3 |
| C5—C6—C7 | 120.21 (19) | C17—C18—H18A | 118.3 |
| Symmetry codes: (i) −x+1, y, −z+5/2; (ii) x, y+1, z; (iii) −x+1, y+1, −z+5/2; (iv) x, y−1, z; (v) −x+1/2, −y+5/2, −z+2. |
This research project was supported by the National Science Council of Taiwan (NSC97–2113-M-033–003-MY2) and by the project of the specific research fields of Chung Yuan Christian University, Taiwan, under grant CYCU-98-CR—CH.
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Brandenburg, K. (2009). DIAMOND. Crystal Impact GbR, Bonn, Germany.
Bruker (2008). SADABS, APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.
Kitagawa, S., Kitaura, R. & Noro, S. (2004). Angew. Chem. Int. Ed. 43, 2334–2375.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.
The synthesis of coordination polymers has been a subject of intense research owing to their interesting structural chemistry and potential applications. A large number of these compounds have been synthesized by the reactions of metal salts and organic dicarboxyl acids or bipyridines (Kitagawa et al. 2004). As a further study in this field, the structure of the title compound is reported.
The asymmetric unit of the title compound consists of one CoII atom, one 3-nitrobenzoate anion and two half 4,4'-bipyridine ligands (Figure 1). The octahedral metal ions are coordinated by four nitrogen atoms of two pairs of crystallographically independent 4,4'-bipyridine ligands and two oxygen atoms of two symmetry related 3-nitro benzoate anions. The Co—O bond length is 2.0557 (13) Å and the average Co—N distance amount to 2.1836 (19) Å. The metal centers are linked via the 4,4'-bipyridine ligands into layers and the anions are only terminal bonded to the CoII atoms (Figure 2). Thus, this structure is different from the analogous nickel compound with the same ligands (Biradha et al. 1999).