Crystal structure of <i>catena</i>-poly[[[tetraaquacobalt(II)]-μ₂-1,5-dihydroxynaphthalene-2,6-dicarboxylato] dimethylformamide disolvate]

The asymmetric unit of the title compound, {[Co(C₁₂H₆O₆)(H₂O)₄]·2C₃H₇NO} _<i>n</i> or {[Co(H₂dondc)(H₂O)₄]·2DMF} _<i>n</i> , comprises half of a Co^II ion, half of a 1,5-di-hydroxy-naphthalene-2,6-di-carboxyl-ate dianion (H₂dondc^2-), two water mol-ecules and a di-methyl-formamide (DMF) mol-ecule. The Co^II ion, which is located on a crystallographic inversion center, exhibits a distorted six-coord-inated octa-hedral geometry with two oxygen atoms of the H₂dondc^2- ligand and four oxygen atoms of the water mol-ecules. The carboxyl-ate group is almost coplanar with the naphthalene moiety and shows monodentate coordination to the Co^II ion. The Co^II ions are bridged by the H₂dondc^2- ligand to form a one-dimensional chain. The hy-droxy groups of the ligand have intra-chain hydrogen bonding inter-actions with coordinated water mol-ecules. The coordinated water mol-ecules exhibit not only intra-chain hydrogen bonding inter-actions, but also inter-chain hydrogen-bonding inter-actions. The chains are connected by inter-chain hydrogen-bonding inter-actions and are arranged in parallel to form a two-dimensional network. The chains are further connected by inter-chain hydrogen-bonding inter-actions <i>via</i> the DMF mol-ecules and C-H⋯π inter-actions to give a three-dimensional network.