Spectral characterization and antimicrobial activity of some transition metal complexes of 2-(5-nitro-1H-benzimidazol-2-yl)-4-bromophenol

Abstract

ABSTRACT. MnCl₂, FeCl₃, Ru(DMSO)₄Cl₂, CoCl₂, NiCl₂, PdCl₂, CuCl₂, AgNO₃, CdCl₂ and HgCl₂ complexes of 2-(5-nitro-1H-benzimidazol-2-yl)-4-bromophenol (HL) were synthesized and characterized. The structures of the complexes were confirmed on the basis of elemental analysis, TGA, molar conductivity and magnetic moment measurements, FT-IR, far-IR, FT-Raman, UV-Visible, NMR and fluorescence spectroscopy. According to the analytical and spectral data, the ligand acted as bidentate, via the imine nitrogen and the phenolate oxygen atoms towards to the metal ions except the Ag(I). The complexes were screened for in vitro antibacterial activities against S. aureus, S. epidermidis, E. coli, K. pneumoniae, P. aeruginosa, P. mirabilis and for antifungal activity against C. albicans. Ciprofloxacin and fluconazole were used as reference for antibacterial and antifungal activities of the complexes, respectively. In most cases, the complexes tested showed considerable activity on S. aureus especially, which is a Gram positive bacterium. In addition, the Hg(II) and Ag(I) complexes were found to have superior activity toward all of the microorganisms whereas the Pd(II) and Cd(II) complexes showed considerably antimicrobial effect on S. aureus and C. albicans selectively.

KEY WORDS: Benzimidazole, Bromophenol, Transition metal complexes, Antibacterial, Antifungal

Bull. Chem. Soc. Ethiop. 2019, 33(3), 451-466.   

DOI: https://dx.doi.org/10.4314/bcse.v33i3.6