Syntheses, spectral, thermal and structural characterization of copper(II) complexes of 2,3-pyrazinedicarboxylate with N , N ′-dimethylethylenediamine and 1,10-phenanthroline

Abstract

Two copper(II) complexes of 2,3-pyrazinedicarboxylate (pzdca) with N,N′-dimethylethylenediamine (dmen), [Cu2(pzdca)2(H2O)2(dmen)2] · 6H2O (1) and 1,10-phenanthroline (phen), [Cu(pzdca)(phen)2] · 5.5H2O (2), have been prepared and characterized by elemental analyses, IR, UV/vis, magnetic measurement and single crystal X-ray diffraction. The complexes crystallize in the monoclinic space group P21 /c and triclinic space group P 1, respectively. In both complexes the copper coordinates pyrazine nitrogen and carboxylate oxygen as a bidentate ligand. The coordination sphere around Cu(II) is completed by two N atoms from dmen and four N atoms from phen groups and one axial position occupied by the carboxyl O atom from the symmetry related molecule in 1. The coordination sphere should be described as a distorted octahedral and (5 + 1)-geometry in 1 and distorted octahedral geometry in 2. While 1 shows a first dimeric arrangement, 2 is a monomer. The thermal analyses show that 1 and 2 decompose completely in four and five step thermal processes at 20–600°C temperature intervals.