Synthesis, spectral characterization and biological studies of copper(II) complexes bearing azomethine thiourea ligands

Cytotoxic metal complexes have drawn significant attention from biochemists nowadays. These bioactive coordination compounds of potential ligands with biological functional groups and suitable metal ions have garnered considerable interest. In this study, hybrid azomethine thiourea ligands and their copper(II) complexes were prepared and studied using modern physicochemical techniques. The spectral data have shown that the coordination was carried out through N, N, O, and S atoms. One unpaired electron d9 configuration and the distorted square-planar environment were suggested for the synthetic copper(II) complexes. The electrochemical properties of the Schiff base thiourea copper(II) complexes were investigated. The antioxidant activities of all azomethine thiourea copper(II) complexes were identified by DPPH method using curcumin as a positive control. In vitro cytotoxic activity against human cancer cell lines, hepatocellular carcinoma (HepG-2) and human lung adenocarcinoma (A549) of the received copper(II) complexes was examined. The obtained results have indicated that [Cu(II)LCl] possessed the best cytotoxicity for HepG-2 and A549 with 50% inhibitory concentration (IC50) = 2.41 and 1.88 µg/ml, respectively.