Spectral characterizations and antibacterial effect of 2-(5-R-1H-benzimidazol-2-YL)-4-methyl/bromo-phenols and some metal complexes

2-(5-H/Cl/Me/NO2-1H-benzimidazol-2-yl)-4-Me/Br-phenols (HL1–HL5) were synthesized. HL1 complexes with Cu(NO3)2, AgNO3, Zn(ClO4)2 and; HL4, HL5 complexes with Zn(ClO4)2 were prepared. The structures of the compounds were confirmed on the basis of elemental analysis, molar conductivity, magnetic moment, FT-IR, 1H- and 13C-NMR. Antibacterial activity of the ligands and the complexes were evaluated using the disk diffusion method in dimethyl sulfoxide (DMSO) as well as the minimal inhibitory concentration (MIC) dilution method, against nine bacteria, and the results were compared with penicillin–G and oxytetracycline. While HL1 ligand has considerable antibacterial activity on B. cereus only; it’s Ag(I) complex show antibacterial effect toward almost all the bacteria. It is highly interesting that HL5 and [Zn(HL5)(L5)]ClO4 exhibit considerable high antibacterial activity toward K. pneumoniae, B. cereus, S. epidermidis and B. subtilis. KEY WORDS: Benzimidazole, Phenol, Metal complexes, Antibacterial activity Bull. Chem. Soc. Ethiop. 2010, 24(3), 391-400.