Bioactive O^N^O^ Schiff base appended homoleptic titanium(iv) complexes: DFT, BSA/CT-DNA interactions, molecular docking and antitumor activity against HeLa and A549 cell lines.

Abstract

Five new homoleptic derivatives of titanium(iv) have been developed and characterized by physicochemical techniques. Metal complexes, TiH2L1 [(C38H26N6O4)Ti], TiH2L2 [(C38H24F2N6O4)Ti], TiH2L3 [(C38H24Cl2N6O4)Ti], TiH2L4 [(C38H24Br2N6O4)Ti] and TiH2L5 [(C38H24N8O8)Ti], were obtained by treating Ti(OPri)4 with appropriate ONO ligands (H2L1-H2L5) in anhydrous THF as solvent. The electronic structures and properties of titanium(iv) complexes (TiH2L1-TiH2L5) and ligands (H2L1-H2L5) were examined by DFT studies. The stability of all synthesized derivatives was assessed by a UV-visible technique using 10% DMSO, GSH medium and n-octanol/water systems. The binding interactions of BSA and CT-DNA with respective titanium(iv) complexes were successfully evaluated by employing UV-visible absorption, fluorescence, circular dichroism (CD) techniques and docking studies. The in vitro cytotoxicity of TiH2L2, TiH2L3 and TiH2L4 complexes was assessed against HeLa (human epithelioid cervical cancer cells) and A549 (lung carcinoma) cell lines. The IC50 values of TiH2L2, TiH2L3 and TiH2L4 were observed to be 28.8, 14.7 and 31.2 μg mL-1 for the HeLa cell line and 38.2, 32.9 and 67.78 μg mL-1 for A549 cells, respectively. Complex TiH2L3 exhibited remarkably induced cell cycle arrest in the G1 phase and 77.99% ROS production selectivity in the HeLa cell line.