Experimental and Theoretical Investigations of Some Tridentate Substituted Salicylaldimines

Five substituted tridentate salicylaldimines, (E)-2-((2-hydroxybenzylidene)amino)phenol, (E)-2-(((2-hydroxyphenyl)imino)methyl)-4-nitrophenol, (E)-4-chloro-2-(((2-hydroxyphenyl)imino)methyl)phenol, (E)-2-(((2-hydroxyphenyl)imino)methyl)-4-methoxyphenol, (E)-4-bromo-2-(((2-hydroxyphenyl)imino) methyl)-6-methoxyphenol were synthesized and characterized by elemental analysis, IR, UV and NMR (1H and 13C). Moreover, theoretical calculations using density functional theory were performed on the optimized structures of the salicylaldimines to augment the experimental data. The antibacterial potentials of the compounds were evaluated by agar-well diffusion method and the total antioxidant capacities determined by phosphomolybdenum assay. The result showed that the methoxy-substituted compound exhibited the highest antibacterial and antioxidant activities while the nitro-substituted compound exhibited the least activities. This implies that the electron donating group on the compound increases its antibacterial and antioxidant activities.