Effect of tunable redox behavior of bis chelate substituted 1,10-phenantroline Cu(II) complexes on its reaction with superoxide anion in DMSO. Toward a simple criterion to identify a SOD-like mechanism.

In this work we report a series of Cu(II) complexes [Cu(N-N)2(X)]+, (N-N=substituted 1,10-phenanthroline derivatives and X=Cl- or NO3-), with tunable E1/2 for electrochemical reduction [CuII(N-N)2(X)]++1e-⇌[CuI(N-N)2]+X-. The disproportion of O2•- was explored in presence of the electro-generated species [CuI(N-N)2]+ using cyclic voltammetry in a non-aqueous media, arising a new simple method to propose a SOD-like mechanism, which can be used as a quick guide test for a compound, before being proven in biological assays. It was found that complexes with high negative half wave potential values (E1/2) for Cu(II)/Cu(I) couple shown a current increment for oxygen reduction, related to the capability of the disproportion of this reactive oxygen species.