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

Abstract

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.