New Complexes of organotin(IV) and organosilicon(IV) with 2-{(3,4-dimethoxybenzylidene)amino}-benzenethiol: Synthesis, spectral, theoretical, antibacterial, docking studies

Abstract

New series of dimethyl-, dibutyltin(IV), trimethylsilicon(IV), and phenylsilicon(IV) compounds with bidentate nitrogen and sulphur donor ligands have been synthesized with the 2-{(3,4-dimethoxybenzylidene)amino}-benzenethiol (LH), in molar ratios of 1:1 and 1:2. For structure elucidation, all produced compounds were characterized using IR, UV–vis, elemental analysis, conductance measurements, NMR (1H, 13C, 29Si, 119Sn) spectroscopy techniques. The 2-{(3,4-dimethoxybenzylidene)amino}-benzenethiol behaves as monofunctional bidentates, interacting with the tin and silicon atom via the thiolic-sulphur and azomethine-nitrogen atoms. Compound 1, 3, and 5 have a five-coordinated trigonal bipyramidal geometry surrounding the metal atoms, whereas Compound 2, 4, and 6 have deformed octahedral structures. The optimum geometrical parameters, including bond length, bond angles, HOMO, LUMO, electrophilicity index, chemical hardness, global softness, and mulliken atomic charges, were determined using density functional theory-based methods (DFT). The studied compounds and their ligands were simultaneously evaluated for antibacterial activity in-vitro and compared to streptomycin. The binding affinity of compound with bulky group and hydrogen bond acceptor groups is more in comparision of other compounds. The structure activity relationship revealed that compounds with bulky and hydrogen bond acceptor group will enhance the antibacterial activity agaisnt Staphylococcus aureus.