Comparative Study of Ni(II) Complexes with Dithiocarbazate- and Thiosemicarbazone-Based Ligands: Synthesis, Crystal Structures, and Anticancer Activity.

The present work reports a comparative study of thiosemicarbazone (H2L1) and dithiocarbazate (H2L2) ligands and their Ni(II) complexes; [Ni(L1)(PPh3)] (1); [Ni(L1)(Py)] (2); [Ni(L2)(PPh3)] (3); and [Ni(L2)(Py)] (4). All compounds were characterized by spectroscopy analysis; and the complexes were also characterized by single-crystal X-ray diffraction. The crystal structures of the complexes revealed a distorted square planar geometry with the Ni(II) atoms coordinated to a double-deprotonated and tridentate ligand molecule by the ONS donor system. The coordination sphere is completed by the incorporation of pyridine or triphenylphosphine coligands at the metal center. Biological assays were conducted against the cell lines breast cancer (MCF-7); cisplatin-resistant ovarian cancer (A2780cis); lung cancer (A549); and nontumoral lung (MRC-5). The results show that cytotoxicity was significantly enhanced upon complexation for complexes (2) and (4); whereas it was suppressed for complexes (1) and (3) against the A2780cis and A549 cell lines. Notably; complex (2) exhibited superior cytotoxicity compared to cisplatin against both MCF-7 and A2780cis.