Design, synthesis, characterization and biological studies of copper(II) complexes with 2-aminobenzimidazole derivatives as biomimetic agents

Four novel copper(II) complexes of 2-aminobenzimidazole derivatives (obtained from the Knoevenagel condensation of acetylacetone (obtained from acetylacetone and halogen-substituted benzaldehydes) and 2-aminobenzimidazole) were synthesized. They were characterized using elemental analysis, molar conductance measurements, and fast atom bombardment mass, Fourier transform infrared, NMR, UV-visible and electron paramagnetic resonance spectroscopies. On the basis of the spectral studies, a distorted square planar geometry was assigned for all the complexes. The antibacterial screening of the ligands and their complexes revealed that all the complexes had higher activities than the free ligands. Superoxide dismutase and antioxidant activities of the copper complexes were also studied. The shifts in E-p, E-1/2, I-pc and I-pa values were explored for the interaction of the complexes with calf thymus DNA using the electrochemical technique.