New zinc(II) N4 tetradentate Schiff base complex: A potential cytotoxic metallodrug and simple precursor for the preparation of ZnO nanoparticles.

A novel Schiff base Zn(II) complex using a tetradentate Schiff base ligand was synthesized and characterized. The results of cytotoxicity assay revealed that the prepared complex induced cytotoxicity in a breast cancer cell line. Thus, the binding of the Zn(II) complex to human serum albumin (HSA) was investigated using spectroscopic and molecular docking methods. The fluorescence data showed that the Zn(II) complex quenched protein fluorescence by a static quenching mechanism. The binding constant (K), number of binding sites (n), and thermodynamic parameters were calculated and showed that the Zn(II) complex binds to HSA through hydrogen bond and Vander Waals interactions with one binding site. Protein-ligand docking analysis confirmed that the Zn(II) complex binds to residues located in the subdomain IIA of HSA. This Zn(II) complex was used for the preparation of ZnO nanoparticles, and their photocatalytic activities were examined via photocatalytic degradation of ethidium bromide (EBr) in the absence of UV-vis irradiation. The results showed that these nanoparticles are promising materials for photocatalytic degradation.