New Schiff-base ligands containing thiophene terminals: Synthesis, characterization and biological activities

Schiffbase ligand C18H24N2S2 was synthesized in the reaction of aromatic aldehyde 4-methylthiophene-2-carbaldehyde with hexane-1,6-diamine. Also, C20H28N2S2 was obtained reacting 4-methylthiophene-2-carbaldehyde with octane-1,8-diamine. The ligands have been characterized by NMR (H-1, C-13), FT-IR and mass spectroscopy. The energies and the atomic configurations of the ligands have been optimized within Density Functional Theory. The NMR and FT-IR spectra of the compounds were calculated on their optimized molecular structures, and they were compared with their corresponding experimental NMR and FT-IR spectra. The antibacterial activities of synthesized compounds were investigated by using Broth Micro-Dilution method. They were effective on Staphylococcus aureus ATCC 25923 bacteria as much as the effect created by the antibiotic in the same dose. The cytotoxic effects the ligands were pronounced on the cancer cell lines while no harm of them was observed on the healthy cells. (C) 2021 Elsevier B.V. All rights reserved.