1D polymeric copper(II) complexes containing bridging tridentate pyrazinato and terminal chloro or azido anions. Synthesis, spectral, structural and thermal study of [CuCl(pyrazinato)(H2O)]n and [Cu(N3)(pyrazinato)(H2O)]n complexes

Abstract

The polymeric complexes [CuCl(pyrazinato)(H2O)]n (1) and [Cu(N3)(pyrazinato)(H2O)]n (2) have been synthesized and characterized by spectroscopic methods and X-ray crystallography. The overall spectral results indicate that these complexes contain tridentate pyrazinato ligands, terminal chloride or azide groups and aqua molecules. In the structure of complex (1), each copper atom, which is chelated by O(1) and N(1) atoms of the pyrazinato anions, links Cl(1) atom, O(3) atom from an aqua molecule and the second nitrogen, N(2) from a pyrazinato group of a neighbouring unit giving rise to a 1D polymeric structure. The structure of complex (2), which is very similar to 1 features five coordinate copper(II) atom, N, N,O-tridentate pyrazinato ligand, terminal azido ligand, aqua molecule and 1D polymeric structure. There are different types of hydrogen bonds in both complexes. The thermal decomposition of complexes (1) and (2) was investigated thermogravimetrically in nitrogen atmosphere.