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Mechanism of the quenching of *[Ru(bpy)3]2+ by peroxodisulfate and its application for photoinduced oxidation reactions

The earlier work (J. Phys. Chem., 1984, 88, 1840) from Bard’s laboratory has provided a model for the quenching of the excited state of [RuII(bpy)3]2+ by [S2O8]2- and was widely used since then for the analysis of photo-driven oxidation reactions. In our work we resolve several inconsistencies found for previously proposed model and explain the mechanism of the oxidative quenching of the *[RuII(bpy)3]2+ by peroxydisulfate in terms of the mechanism consistent with the formation of the precursor complex through the photo-excitation of the ground state ion pair in addition to bimolecular quenching pathway. The proposed model accurately describes experimental results for the quenching of *[Ru(bpy)3]2+ in a wide range of peroxydisulfate concentrations. The new model also resolves some discrepancies in observed KIP and kET compared to previously reported values based on the treatment proposed by Bard et. al. It also provides convenient guidance for accurate evaluation of photochemical parameters, such as quantum yields in photo-driven oxidation reactions which employ [Ru(bpy)3]2+/persulfate couple.

J. Phys Chem. A, 2013, 117, 10311–10319, DOI: 10.1021/jp407573d.