Electron transfer reactions of organic sulfoxides with photochemically generated ruthenium(III)–polypyridyl complexes

The electron transfer (ET) reaction of aryl methyl sulfoxides with ruthenium(III)–polypyridine complexes is sensitive to the change of substituent in the aryl moiety of ArS(O)CH3 and ligand of Ru(III) complex. The detection of sulfoxide radical cation as the transient by conventional flash photolysis confirms ET in the rate-controlling step. The successful application of Marcus cross relation of ET leads to the evaluation of self-exchange rate constant of ArS+(O)CH3/ArS(O)CH3 as 4.0×105 M−1 s−1 similar to organic sulfides. Comparison with the reactivity of iron(III)–polypyridyl complexes points out that both reactivity and ρ values are higher with Ru(III) complexes.