trans-Diaquabis(5-carboxy-1H-imidazole-4-carboxylato-kappa2N3,O4)cobalt(II) 4,4'-bipyridine solvate.

In the title compound, [Co(C(5)H(3)N(2)O(4))(2)(H(2)O)(2)].C(10)H(8)N(2), the Co atom is trans-coordinated by two pairs of N and O atoms from two monoanionic 4,5-dicarboxyimidazole ligands, and by two O atoms from two coordinated water molecules, in a distorted octahedral geometry. The 4,4'-bipyridine solvent molecule is not involved in coordination but is linked by an N-H...N hydrogen bond to the neutral [Co(C(5)H(3)N(2)O(4))(2)(H(2)O)(2)] molecule. Both molecules are located on inversion centers. The crystal packing is stabilized by N-H...N and O-H...O hydrogen bonds, which produce a three-dimensional hydrogen-bonded network. Offset pi-pi stacking interactions between the pyridine rings of adjacent 4,4'-bipyridine molecules were observed, with a face-to-face distance of 3.345 (1) angstroms.