Synthesis, characterization, and antibacterial effect of 4-methoxy-2-(5-H/Me/Cl/NO2-1H-benzimidazol-2-yl)-phenols and some transition metal complexes

Abstract

4-Methoxy-2-(5-H/methyl/chloro/nitro-1H-benzimidazol-2-yl)-phenol (HLX; X=1-4) ligands and HL1 complexes with Fe(NO3)(3), Cu(NO3)(2), AgNO3, and Zn(NO3)(2) were synthesized and characterized. The structures of the compounds were confirmed on the basis of elemental analysis, molar conductivity, magnetic moment, FT-IR, UV-visible, and H-1- and C-13-NMR. Antibacterial activity of the free ligands, their hydrochloride salts, and the complexes was evaluated using the disk diffusion method in dimethyl sulfoxide (DMSO) as well as the minimum inhibitory concentration (MIC) dilution method, against 9 bacteria, and the results were compared with penicillin-G and oxytetracycline. It was observed that HL1, [Ag(HL1)](NO3), and [Cu(L-1)(2)](H2O)(2) are effective on S. epidermidis, S. aureus, and B. subtilis (gram+) organisms compared with the other compounds. All compounds except HL4 and [Zn(L-1)(H2O)(2)]NO3 showed antibacterial activity on S. aureus.