Poly[(μ-3,5-dinitro-2-oxidobenzoato)(μ-3-hydroxy-pyridine)copper(II)].

A new coordination polymer, [Cu(C(7)H(2)N(2)O(7))(C(5)H(5)NO)](n), exhibits a double-chain structure, in which 3,5-dinitro-2-oxidobenzoate and 3-hydroxy-pyridine both act as bridging ligands, -connecting adjacent copper(II) centers to form an infinite double-stranded chain. The asymmetric unit contains one Cu(II) ion, one 3,5-dinitro-2-oxidobenzoate ligand and a 3-hydroxy-pyridine ligand. Coordination by one N atom and three O atoms from two different 3,5-dinitro-2-oxidobenzoate ligands and a 3-hydroxy-pyridine ligand creates a square-planar Cu(II) center, which is augmented by a less tightly bonded fifth phenol O atom to form a square-pyramidal five-coordinate complex with an essentially planar base. The double-stranded chains are stabilized by intra-chain π-π inter-actions [the centroid-to-centroid distance between adjacent aromatic rings is 3.719 (7) Å], and further linked through O-H⋯O hydrogen bonds, forming a three-dimensional supra-molecular network.