The oxo(phosphine)ruthenium(IV) complexes [Ru(bpy)[sub 2](O)PR[sub 3]](ClO[sub 4])[sub 2] (bpy = 2,2[prime]-bipyridine; PR[sub 3] = P(C[sub 6]H[sub 5])[sub 3], P(p-C[sub 6]H[sub 4]OCH[sub 3])[sub 3], P(p-C[sub 6]H[sub 4]CH[sub 3])[sub 3], P(p-C[sub 6]H[sub 4]F)[sub 3], P(C[sub 6]H[sub 5])(p-C[sub 6]H[sub 4]CF[sub 3])[sub 2], P(p-C[sub 6]H[sub 4]CF[sub 3])[sub 3]) cleanly oxidize sulfides to sulfoxides and in separate experiments oxidize sulfoxides to sulfones. The substrate oxidations are second order overall, first order in substrate concentration and first order in ruthenium concentration. Through the use of para-substituted thioanisoles and para-substituted methyl phenyl sulfoxides, linear free energy relationship analyses of the kinetics of substrate oxidations by [Ru(bpy)[sub 2](O)P(C[sub 6]H[sub 5])[sub 3]](ClO[sub 4])[sub 2] were conducted. For the oxidation of sulfides to sulfoxides, an excellent correlation (R[sup 2] = 0.99) was obtained between log (k[sub X]/k[sub H]) and the [sigma][sup [minus]] values for the substituents of para-substituted thioanisoles ([rho] = [minus]1.56). For the oxidation of sulfoxides to sulfones, a good correlation (R[sup 2] = 0.98) was obtained between log (k[sub X]/k[sub H]) and the [sigma][sup +] values for the substituents of para-substituted methyl phenyl sulfoxides ([rho] = [minus]0.42). 57 refs., 8 figs., 2 tabs.