Synthesis, characterization and biological activities study of metal complexes of 5,6-dimethylbenzimidazole with Co(II), Cu(II), Cd(II) and Hg(II)

Abstract

The present work aimed at the synthesis of cobalt(Ⅱ), copper(Ⅱ), cadmium(Ⅱ) and mercury(Ⅱ) complexes of 5,6-dimethylbenzimidazole by simple and straight forward methods. Several elemental, spectroscopic and thermal studies such as; solubility, melting point, elemental analysis, FTIR spectroscopy, UV–visible spectroscopy, magnetic susceptibility, conductivity test, TGA, DSC and XRD were carried out to characterize the synthesized complexes. Elemental analysis (C, H, N, M) data confirmed 1:2 metal to ligand ratio represented as [M(L)2Cl2]. UV–visible spectra and Magnetic susceptibility values suggested tetrahedral geometry of the synthesized metal complexes. The lattice types were predicted by XRD data and conductivity values indicated non-electrolytic nature of the complexes. TGA and DSC data demonstrated their thermal decomposition patterns as well as formation of corresponding metal oxides. Combining all the analytical results, the proposed empirical formulae of the complexes are [Co(C9H10N2)2Cl2], [Cu(C9H10N2)2Cl2], [Cd(C9H10N2)2Cl2] and [Hg(C9H10N2)2Cl2]. The synthesized complexes were also subjected to antimicrobial and cytotoxicity activity screening. Cd(II) and Hg(II) complexes showed activity against both gram positive and negative bacterial strains at relatively higher concentration. Most of the complexes were less or insensitive to bacterial and fungal strains at lower concentration. All of the synthesized complexes exhibited potential cytotoxic activity.