Synthesis, spectra and biomimetic properties of copper(II)-copper(II) and copper(II)-zinc(II) binuclear complexes with CuN5 chromophores.

X-band electron spin resonance (ESR) and UV-vis spectra of a homobinuclear (Bipy)2Cu-E-Im-Cu(Bipy)23 and a heterobinuclear (Bipy)2Cu-E-Im-Zn(Bipy)23 complexes, E-Im=2-ethylimidazolate ion have been described as possible models for superoxide dismutase (SOD). Magnetic moment and ESR spectral measurements of the homobinuclear complex have shown an antiferromagnetic exchange interaction. From pH-dependent ESR and UV-vis spectral measurements studies, these complexes have been found to be stable over 8.5-10.5 pH range. These complexes catalyze the dismutation of superoxide (O2-) at biological pH. All the observations indicate that these complexes act as good possible models for superoxide dismutase.