MATERIALS SCIENCE AND ENGINEERING C-MATERIALS FOR BIOLOGICAL APPLICATIONS, vol.98, pp.550-559, 2019 (SCI-Expanded)
The reactions of cobalt(II), nickel(II), zinc(II) chlorides and [Pd(DMSO)(2)Cl-2] with 2-acetyl-5-chloro-thiophene thiosemicarbazone (HL) leads to the formation of a series of new complexes: [CoCl2(S-HL)(2)], 1; [Ni(N,S-L)(2)], 2 [ZnCl2(S-HL)(2)], 3 and [PdCl2(N,S-HL)], 4. All the complexes have been characterized by elemental analysis, IR, LC-MS. H-1 and C-13 NMR spectroscopy have been performed for Zn(II) and Pd(II) complexes. The crystal structures of the complexes 1-3 have been determined by single-crystal X-ray diffraction methods. The compounds, (1) and (3), crystallized in the monoclinic crystal system with C2/c space group. In both complexes, the metal centers are fourcoordinated in a distorted tetrahedral configuration by two sulfur atoms from two thiosemicarbazone ligands and two Cl anions. The crystal structure of (2) consists of monomeric entities where the nickel(II) ion exhibit distorted square planar geometry. The coordination geometry around nickel ion is fourcoordinate with four atoms of the two chelating thiosemicarbazone ligands which are in cis position. The tau(4) value of 0.255 obtained from the tau(4) analysis of complex (2) shows that the fourcoordinate geometry around the central nickel ion is close to square planar. Complex (4) is mononuclear, the central ion is coordinated through the sulfur and the azomethine nitrogen atom of neutral ligand. The cytotoxic effects of all complexes were analyzed for three cancer cell lines, Caco-2, DLD-1, and SW620 compared to normal colon epithelial cell line, CCD18Co. Complex (4) is more active against DLD-1, SW620 and Caco-2 than CCD18Co. The efficiency of complex (4) is more effective in aggressive cancer cell lines. Therefore, it can be used as a new chemotherapeutic, especially in the treatment of resistant cancer types caused by long-term use of platinum-based drugs.