Poly[[bis-{μ2-1,2-bis-[(1H-imidazol-1-yl)meth-yl]benzene}(μ4-9,10-dioxo-9,10-dihydro-anthracene-1,4,5,8-tetra-carbox-yl-ato)dicobalt(II)] dihydrate].

The title complex, {[Co2(C18H4O10)(C14H14N4)2]·2H2O} n was synthesized from CoCl2·6H2O, 9,10-dioxo-9,10-dihydro-anthracene-1,4,5,8-tetra-carb-oxy-lic acid (H4AQTC) and 1,2-bis-[(1H-imidazol-1-yl)meth-yl]benzene (o-bix) in water. The anthraquinone unit is located about a crystallographic center of inversion. Each asymmetric unit therefore contains one Co(II) atom and one o-bix ligand, as well as half an AQTC(4-) ligand and an additional solvent water mol-ecule. The Co(II) ions are tetra-hedrally surrounded by two O atoms from two AQTC(4-) anions and by two N atoms from two o-bix ligands, forming a two-dimensional coordination polymer. The solvent water mol-ecules are connected to the carboxyl-ate groups by O-H⋯O hydrogen bonds. Additional weak C-H⋯O hydrogen bonds are observed in the crystal structure.