Synthesis, characterization and catecholase biomimetic activity of novel cobalt(II), copper(II), and iron(II) complexes bearing phenylene-bis-benzimidazole ligand

Transition metal complexes of Co(II), Cu(II), and Fe(II) bearing a rigid symmetrical 2,2′-(1,2-phenylene)bis(1H-benzimidazole) ligand, PhBIm2, were synthesized fully characterized by ESI-MS, FT-IR, 1H NMR (for paramagnetic species), UV–Vis spectroscopy microanalytical techniques. Besides the cobalt complex was subject X-ray structural analysis. The molecular crystal structure PhBIm2Co(II)Cl2 revealed center in pseudo-tetrahedral environment with not significant lengthening or compressing bonds PhBIm2 framework upon chelation ligand. All catalyze aerobic oxidation o-catechol to o-quinone under mild conditions. results show that rate depends on electronic stabilizing effect rather than steric hindrance Kinetic parameters (Vmax, kcat, KM) estimated mean Michaelis–Menten model Lineweaver–Burk plot. Catechol rates 2–4 are same order magnitudes mononuclear dinuclear Cu(II) imidazole-based ligands but lower observed for catecholase enzyme.