Copper(I) complexes of N-(2/4 methoxy/2-chloro-4-nitro)phenyl-N′ (methoxycarbonyl)thiocarbamides as potential anticancer agents: Synthesis, crystal structure, in vitro cytotoxicity and DNA damage studies

Abstract

Synthesis and structural assignment of four trigonal planar copper(I) complexes (1a–4a) having the general formula [Cu(CH3OCONHCSNHR)2Cl] where R = 2-methoxyphenyl (1), 4-methoxyphenyl (2), 2-chloro 4-nitrophenyl (3) and 2-methoxy 4-nitrophenyl (4) have been described. The characterization were done by elemental, spectroscopic (FT-IR, 1H, 13C NMR, UV–Vis), TG analysis and single crystal X-ray studies of ligands 1, 3 and complex 2a. In the complex 2a the methoxycarbonyl groups adopt cis conformation with respect to chlorine atom and are nearly coplanar with the central plane in a trigonal planar geometry. Cyclic voltammogram of complexes 1a–4a displayed quasi-irreversible redox behaviour corresponding to Cu(I)/Cu(II) couple. In vitro cytotoxicity of the ligands and their copper(I) complexes screened against five human cancer cell lines revealed that complexes were two to three times more potent than the ligands against all the cell lines. DNA damage study of complexes against 2008, C13* (cervical cancer) and IGROV-1 (ovarian cancer) cell lines indicated that cytotoxicity exerted by them is mainly through perturbation of DNA structure.