Syntheses, Structures and Cytotoxicity of Cu(II) Complexes with α‐Amino acid derived Benzamidines

Abstract

AbstractN‐(diethylthiocarbamoyl)benzimidoyl chloride reacts with methyl esters of glycine, L‐alanine, L‐valine under formation of pro‐ligands 1 which undergo de‐esterification in reactions with Cu(CH3COO)2 and finally form complexes 2 with the compositions of [{Cu(L‐gly)}4] (2 a), [{Cu(L‐ala)}∞] (2 b) and [{Cu(L‐val)}∞] (2 c). In all complexes, Cu(II) ion is coordinated by a dianion {L2−} via its (O,N,S) donor set and a bridging carboxylate O atom, and thus, adopts a distorted square‐planar coordination sphere. Treatment of complexes 2 with equimolar amounts of o‐phenanthroline results in the formation of square pyramidal ternary complexes with the compositions of [Cu(L)phen] (L=L‐gly, L‐ala, L‐val) (3). Antiproliferative effects of the compounds on MCF‐7 and Hep‐G2 cancer cells were studied. Generally, the ternary complexes 3 are more active than the complexes 2 and the pro‐ligands 1. In each series of compounds, the derivatives of L‐valine show higher cytotoxicity than those of L‐alanine and glycine.