Synthesis, characterization, and biological applications of zinc(ii) complexes of the methylthiosalicylate ligand

Abstract

A series of Zn(II) complexes, [Zn(MTS)₂(TMEDA)] (1), [Zn(MTS)₂(2,2′-bipy.)] (2), [Zn(MTS)₂(1,10-phen.)] (3) and [Zn(MTS)₂(4,4-bipy.)₂]_n (4), where MTS = methylthiosalicylate, TMEDA = tetramethyl ethylenediamine, bipy. = bipyridyl, and phen. = phenanthroline, have been synthesized and characterized by single crystal X-ray analysis and other spectroscopic techniques. The geometry of complex 3 is distorted square pyramidal around the Zn center, while complex 2 has distorted trigonal bipyramidal geometry. Complexes 1 and 4 show distorted tetrahedral geometry, of which complex 4 has a zig-zag polymeric structure. Due to differences in geometries, these Zn complexes are expected to exhibit differences in their biological activities. We have carried out studies on the DNA and protein binding, anticancer activity and cytotoxicity of these complexes. The anticancer activities were cell-line dependent; however, complex 4 was found to be the most active complex.