Synthesis, DNA binding and antibacterial activity of metal(II) complexes of a benzimidazole Schiff base

Abstract

The benzimidazole derivative (E)-2-((4-(1H-benzo[d]imidazol-2-yl)phenylimino)methyl)-4-bromo phenol and the corresponding Zn(II), Ni(II), Cu(II), and Pd(II) complexes were prepared. The synthesized ligand and complexes were fully characterized and the ligand structure confirmed by single crystal X-ray diffraction analysis. The ability of this compound and its complexes to bind to DNA was first investigated with DNA thermal denaturation experiments, in general showing weak interactions. Additionally, UV–Vis absorption spectroscopy was used to assess the binding to DNA and the corresponding binding constants (Kb) were calculated suggesting an intercalative mode of binding for the benzimidazole ligand. All compounds were screened for their antibacterial activity and the Ni(II) complex showed promising results against all bacterial strains (Gram positive and Gram negative) while the rest of the compounds showed activity against selective strains.