Diaquabis(2,2′-biimidazole)cobalt(II) 4,4′-dicarboxybiphenyl-3,3′-dicarboxylate

Abstract

In the title compound, [Co(C6H6N4)2(H2O)2](C16H8O8), the CoII cation and the organic anion occupy different crystallographic inversion centres and, as a consequence, the asymmetric unit comprises two half-mol­ecules. The benzene groups are coplanar. The four coordinating N atoms of the two bidentate biimidazole ligands define the equatorial plane of a slightly distorted octa­hedral CoO2N4 geometry, and the water O atoms lie in the axial coordination sites. Translational (a,) and inversion-related symmetry operations link the Co complex mol­ecules and the negatively charged carboxyl­ate anions via inter­molecular N—H⋯O and O—H⋯O hydrogen bonds into sheets parallel to (01). The coordinated water mol­ecules connect the sheets through O—H⋯O hydrogen bonds, forming a three-dimensional framework. In addition, two intra­molecular O—H⋯O hydrogen bonds are observed between the carboxyl and carboxyl­ate groups.