CNSL green catalyst of sulfone-based Schiff base ligand and its metal(II) complexes: Antibacterial, anticancer and molecular docking studies

Nowadays, the use of many organic solvents poses a serious threat to the atmosphere due to the release of toxic by-products. Therefore, the use of solvent-free green catalysts to solve this problem has brought about a significant change in the field of chemistry. Based on this, a Schiff base ligand is synthesized from the condensation of dapsone (4,4′-sulfonyldianiline) and 4-dimethylaminobenzaldehyde in the presence of green catalyst especially cashwnut shell liquid (CNSL) catalyst. Furthermore, metal(II) complexes Co(II), Ni(II), Cu(II) and Zn(II) were synthesized from a new Schiff base ligand. The composition of the Schiff base ligand and its metal(II) complexes was analyzed by various analytical techniques such as UV, IR, NMR (H¹ & C¹³), Mass spectra and SEM analysis. Schiff base ligand and its complexes were tested in vitro to evaluate their antimicrobial activity against Escherichia coli, Staphylococcus aureus and Candida albicans using a well diffusion method. Schiff base ligand and its complexes were found to exhibit significant antimicrobial activity against all tested bacterial species. The anticancer properties of the Schiff base ligand and its copper(II) complex are evaluated using MTT assay on the human breast cancer cell line MCF-7. Molecular docking study of Cu(II) complex with the target protein HER2 revealed good binding potential.