Decomposition of allantoin in the presence of Cu(II) ions resulting in the formation of a coordination polymer containing oxalate species

A novel Cu(II) coordination polymer, [Cu(ox)(DMSO)2]n (1) (ox-oxalate dianion, DMSO-dimethyl sulphoxide) has been prepared in the reaction of copper nitrate dihydrate and allantoin (5-ureidohydantoin) in DMSO/water solution. Compound (1) crystallizes in the monoclinic, space group P121/c1 with a = 5.1785(7), b = 13.6311(18), c = 8.5386(12) Å, β = 107.524(12)°, V = 574,76(14) Å3, Z = 4, Dcal = 1779 mg/m3, R1 = 0.0449. The metal ion coordinates through four oxygen atoms belonging to two bidentate bridging oxalate ligands, and two oxygen atoms from two DMSO ligands forming an elongated octahedron. The crystal structure was confirmed by FT-IR and Uv–vis spectroscopic data.