Crystal structure of catena-poly[aqua­bis­­(4-cyano­benzoato-κO)copper(II)]-μ-N,N-di­ethyl­nicotinamide-κ2N1:O]

The asymmetric unit of the title polymeric compound, [Cu(C8H4NO2)2(C10H14N2O)(H2O)]n, contains one CuII atom, one coordinating water mol­ecule, two 4-cyano­benzoate (CB) ligands and one coordinating N,N-di­ethyl­nicotinamide (DENA) mol­ecule. The DENA ligand acts as a bis-monodentate ligand, while the CB anions are monodentate. Two O atoms of the CB ligands, one O atom of the water mol­ecule and the pyridine N atom of the DENA ligand form a slightly distorted square-planar arrangement around the CuII atom which is completed to a square-pyramidal coordination by the apically placed O atom of the DENA ligand, with a Cu—O distance of 2.4303 (15) Å. In the two CB anions, the carboxyl­ate groups are twisted relative to the attached benzene rings by 2.19 (12) and 3.87 (15)°, while the benzene rings are oriented at a dihedral angle of 5.52 (8)°. The DENA ligands bridge adjacent Cu2+ ions, forming polymeric coordination chains running along the b axis. In the crystal, strong water–carboxyl­ate O—H⋯O hydrogen bonds link adjacent chains into layers parallel to (10-1) and weak C—H⋯O hydrogen bonds further stabilize the crystal structure. The cyano group C and N atoms of one of the CB ligands are disordered over two sets of sites with equal occupancies.