Diaquabis(pyridine-2-carboxamide-kappa N-2(1),O-2)copper(II) squarate

Abstract

The title compound, [Cu(C6H6N2O)(2)(H2O)(2)](C4O4) [or Cu(pia)(2)(H2O)(2).Sq, where pia is picolinamide or pyridine-2-carboxyamide, and Sq is the squarate dianion, (C4O4)(2-)], has been synthesized and the crystal structure determination is reported. The Cu2+ cation, located on a centre of symmetry, is coordinated by two symmetry-related aqua ligands together with a pair of symmetry-related bidentate pia molecules and exhibits elongated octahedral trans-[CuN2O4] coordination geometry. The unligated Sq dianion also lies on a crystallographic inversion centre. The squarate O atoms link the Sq ions to the metal complex via O-H...O and O-H...N hydrogen bonds. Intermolecular pi-pi and C-H...pi interactions between the moieties also stabilize the crystal structure.