Crystal structure of complexes of bivalent Co, Ni, and Cd with anions of benzoic and 2-(acetylamino)-5-nitrobenzoic acids

The structure of three complexes of bivalent metals (cobalt, nickel, and cadmium) with anions of benzoic (HL1) and 2-(acetylamino)-5-nitrobenzoic (HL2) acids, namely, [Co21 (H2O)2(μ-C4H4N2)]n (I), [NiL2(H2O)5]L2 · 2H2O (II), and [Cd(μ-L2)2(H2O)2]n · 2nH2O (III), is determined. In chainlike structure I, cobalt atoms are connected by bridging pyrazine molecules; structure II contains isolated complexes. In structure III, centrosymmetric (CdOCO)2 cycles and polymeric ribbons are formed due to the coordination of the carboxylate group of the L2 ligand to two cadmium atoms.