The title polymeric compound {(C3H12N2)[Cu(C7H3NO4)2]- 3H2O}n or {(pnH2)[Cu(py-2,3-dc)2]3H2O}n (pn is propane- 1,3-diamine and py-2,3-dcH2 is pyridine-2,3-dicarboxylic acid), was synthesized by reaction of copper(II) chloride dihydrate with a proton-transfer compound, propane-1,3-diammonium pyridine-2,3-dicarboxylate or (pnH2)(py-2,3-dc), in aqueous solution. The anion is a six-coordinate complex (site symmetry 1), with a distorted octahedral geometry around CuII, consisting of two bidentate pyridine-2,3-dicarboxylate groups and two O atoms of bridging ligands from (py-2,3-dc)2 fragments, which are located in trans positions. The (pnH2)2+ cation is disordered over two sites by the center of inversion. Intermolecular hydrogen bonds, – [centroid–centroid distances of 3.539 (3) A ° ] and C—O stacking interactions [O Cg = 3.240 (5) A ° ; Cg is the center of the pyridine ring], connect the various components into a supramolecular structure.
