Solvent-free synthesis of nitrobenzyl Schiff bases: Characterization, antibacterial studies, density functional theory and molecular docking studies

Abstract Three (3) Schiff bases; (E)-1-(2-nitrophenyl)-N-(o-tolyl)methanimine (1), (E)-2-isopropyl-N-(2-nitrobenzylidene)aniline (2),(E)-2-((2-nitrobenzylidene)amino)phenol (3) were synthesized in solvent-free approach and characterized using 1H and 13C NMR, UV–visible, FT-IR, mass spectrometry and purity confirmed by elemental analysis. The structure of 1 was determined by single-crystal X-ray diffraction measurements. The compounds showed moderate antibacterial activities against E. coli, S. typhimurium and 2 selectively active against P. aeruginosa. DFT was used to determine the appropriate geometries and electronic properties at the atomic level. Molecular docking studies were used to complement the antibacterial activities to reveal the compound with the best binding affinity and the important residual interactions.