Structural characterization of a new polymeric Cu(II) complex with unexpected chlorinated pyrazole ligand

Abstract

A newcoordination polymer based on copper(II) and pyrazole (pzH) ligand, [CuCl2(ClpzH)2]n, has been obtained by a very easy synthesis and green reaction conditions using water as solvent. The compound was characterized by single crystal X-ray diffraction elemental analyses, infrared and UV-Vis spectroscopies. For the first time the C(2)-chlorination of the pyrazolyl ring keeping the protonation of the N(2)-H is reported. The polymeric crystal structure consists of a one dimensional infinite neutral chain inwhich the copper(II) atoms are six-coordinated in a slightly distorted octahedral geometry with two nitrogen and four chlorine atoms. In this structure, intermolecular interactions have been identified and studied. Extended structure analyses revealed a novel two-dimensional network supported by intermolecular N\H\Cl and C\H\Cl hydrogen bonds, in addition to the π-π stacking interactions.