Metal-based Antimicrobial Agents: Synthesis, Characterization and Biological Studies of Mannich Base Derivatives of Benzimidazole and Their Metal Complexes

Abstract

Novel Mannich base derivatives of Benzimidazole were prepared through the condensation reaction of benzimidazole derivative with formaldehyde and primary and/ secondary amine. Zinc(II), copper(II), nickel(II) and cobalt(II) complexes of Mannich bases have also been synthesized. All the compounds were fully characterized by, elemental analyses, magnetic moment determination, molar conductivity measurement, thermogravimetric analysis, spectral and analytical data. Experimental results showed that metal complexes act as bi-dentate ligands towards divalent metal ions via azomethine-N and deprotonated-O while suggesting an octahedral geometry. All the compounds were screened for in-vitro antibacterial and antifungal activity against various bacterial and fungal strains. Almost all the compounds showed good potent activity against microorganisms. It was also seen that compounds with complexed form were more active as compared to un-complexed form. The prepared compounds were also screened for their cytotoxicity and results showed that only Ni(II) complexes exhibit some cytotoxicity while all other compounds were almost inactive.