Catena-Poly[[triaqua-cadmium(II)]-μ-pyridine-2,3-dicarboxylato- κ3 N,O 2:O 3]

Abstract

The title polymeric compound, [Cd(C7H3NO4)(H2O)3] n or [Cd(py-2,3-dc)(H2O) 3] n , where py-2,3-dcH2 is pyridine-2,3-dicarboxylic acid, was obtained by the reaction of cadmium(II) nitrate hexa-hydrate with (pipzH2)(py-2,3-dc) as a proton-transfer compound in aqueous solution (pipz is piperazine). The mol-ecular structure shows that only the anionic fragment of the starting proton-transfer compound is present in the complex, while the (pipzH2) 2+ dication has been lost. Each (py-2,3-dc)2- ligand bridges two CdII atoms in two different coordination modes, i.e. one end acts as a monodentate and the other end as a bidentate ligand. The three remaining coordination sites on the metal center are occupied by water mol-ecules. The geometric arrangement of the six donor atoms around the Cd II atom is distorted octa-hedral. In the crystal structure, O - H⋯O and C - H⋯O hydrogen bonds play an important role in stabilizing the supra-molecular structure. © 2008 International Union of Crystallography.