Synthesis, crystal structure, spectroscopy and magnetic properties of a dinuclear Cu II complex with 3,5-bis(2-pyridyl)pyrazole bridging ligand

Abstract

A dinuclear Cu II complex [Cu 2(bpp) 2(H 2O) 2](ClO 4) 2 ( 1) with 3,5-bis(2-pyridyl)pyrazole (Hbpp), has been synthesized and characterized by elemental analyses, thermal analysis, conductance, UV–vis and IR spectra. The crystal structure of 1, determined by X-ray diffraction technique, reveals that two centrosymmetric Cu II centers are bridged by a pair of tetradentate anionic bpp ligands, adopting a square-pyramidal environment with the water ligand occupying the axial site. An interesting feature of this structure is the formation of a two-dimensional supramolecular network through O–H⋯O hydrogen bonds between the water moieties of the cationic [Cu 2(bpp) 2(H 2O) 2] 2+ subunits and perchlorate anions. The magnetic properties of 1 have been investigated by variable-temperature magnetic susceptibility and EPR measurements. Very strong antiferromagnetic interaction between the Cu II centers (with H=− JS 1 S 2, J=−368.3 cm −1) has been observed, and the magneto-structural correlations was analyzed.