Mechanisms of the Dismutation of Superoxide Catalyzed by the Copper(II) Phenanthroline Complex and of the Oxidation of the Copper(I) Phenanthroline Complex by Oxygen in Aqueous Solution

Article abstract of DOI:10.1021/ja00363a012

By using the technique of pulse radiolysis to generate O2^-, it is demonstrated that copper 1,10-phenanthroline ((op)2Cu²⁺) is capable to catalytically dismutating O2^- with a turnover rate constant k_cat. = (5.1 +/- 0.9)*10⁸ M^-1 s^-1.The rate constants of the reduction of (op)2Cu²⁺ and of the oxidation of (op)2Cu⁺ by O2^- have been determined to be (1.93 +/- 0.07)*10⁹ and (2.95 +/- 0.3)*10⁸ M^-1 s^-1, respectively.The kinetic results of the oxidation of (op)2Cu⁺ by molecular oxygen in aqueous solution are interpreted by a mechanism that proceeds via a superoxide intermediate, and the rate constant k_-10 = (5.0 +/- 0.3)*10⁴ M^-1 s^-1 has been determined.The rate constant of the oxidation of (op)2Cu⁺ by H2O2 was measured to be k₂₂ = (937 +/- 20) M^-1 s^-1.