Synthesis, structure, electrochemical properties and superoxide radical scavenging activities of two thiocyanate copper(II) complexes with different pyridyl-benzoxazole ligands

Abstract

Reaction of 2-(2′-pyridyl)benzoxazole (2-PBO) or 2-(4′-pyridyl)benzoxazole (4-PBO) ligands with CuSCN afforded two thiocyanate copper (II) complexes, Cu(2-PBO) (SCN)2 (1) and Cu(4-PBO)2(SCN)2 (2), have been characterized by elemental analysis, UV–Vis, IR spectra and single-crystal X-ray diffraction. The structural analysis reveals that although the structures of complexes 1–2 are both four coordinated and show plane quadrilateral structure, the distorted of complex 1 is greater than 2. The cyclic voltammogram of complexes 1–2 represent quasi-reversible Cu2+/Cu+ pairs. The superoxide radical scavenging test in vitro showed that complex 1–2 had significant antioxidant activity on superoxide radicals, and the activity of complex 2 was higher than that of 1. This may be due to the structure of complex 2 being closer to the Cu, Zn-SOD.