Electron-transfer reactions in [Ru(edta)(pyz)]–(edta = ethylenedinitrilotetraacetate, pyz = pyrazine)

Abstract

The kinetics of reduction of [Ru^III(edta)(pyz)]^–(edta = ethylenedinitrilotetraacetate, pyz = pyrazine) with L-ascorbic acid (H₂A) and catechol(H₂cat) was studied spectrophotometrically as a function of [H₂A] or [H₂cat], pH, ionic strength and temperature (25–45 ° C). The reduction was found to be first order in both the complex and reductant concentrations. The pH dependence of the process(for H₂A) was ascribed to the deprotonation of H₂A. Kinetic data and activation parameters are interpreted in terms of a mechanism involving outer-sphere electron transfer.