A new zinc(II) complex of 2-benzoimidazoledisulfide ligand: synthesis, X-ray crystallographic structure, investigation of CT-DNA and BSA interaction by spectroscopic techniques and molecular docking

This study reports a new zinc(II) complex based on 2-mercaptobenzimidazole ligand. It was synthesized and characterized by UV-visible and Fourier transform infrared spectroscopy. Analysis by X-ray diffraction crystal-lography showed that 2-benzoimidazoledisulfide coordinates to Zn(II) centre as a bidentate ligand via two azomethine nitrogen atoms and forms a seven-member ring. Cytotoxicity activity of this complex and the metal -based anticancer drug (carboplatin) against two human cancer cell lines, i.e. MCF-7 (breast) and HCT-116 (colon), was studied. Comparative activity of the compound against both cell lines was observed. Moreover, the interaction of [Zn(2-benzoimidazoledisulfide)2](NO3)2 with CT-DNA and BSA was extensively investigated by UV - Vis absorption spectroscopy and fluorescence technique to examine its potential for biological activity. DFT calculation of Zn(II) complex was performed to obtain the minimized structure. After that, molecular docking of the optimized structure with BSA and DNA was accomplished to get an insight about their interaction forces. The results of these investigations indicated that the Zn(II) complex interacts with CT-DNA and BSA through static fluorescence quenching. Additionally, these studies proposed the groove binding of the Zn(II) complex to CT-DNA. The results also supported that the hydrogen bonding and van der Waals interactions are the possible pathway for binding of the title complex with CT-DNA and BSA.