Kinetics and mechanism of oxidation of triphenylphosphine with potassium hydrogen persulfate catalysed by aquapropylenediaminetetraacetatoruthenate(III) in water-dioxane medium

Abstract

The kinetics of oxygenation of [(PDTA)Ru^III(H₂O)]⁻ (complex 1) to [(PDTA)Ru^V(O)]⁻ (complex 2) by KHSO₅ was studied spectrophotometrically by monitoring the appearance of the characteristic oxo peak (393 nm, ε_max³⁹³=8200) at a fixed pH 6.0 and ionic strength 0.2 M (NaClO₄). The time course of the oxygen atom transfer from complex 2 to PPh₃ was investigated by following the disappearance of characteristic oxo-peak of the oxo-complex 2 as a function of PPh₃ concentration and temperature (30-50°C) at a fixed pH 6.0 and ionic strength of 0.2 M (NaClO₄). Activation parameters for both the oxygenation of complex 1 to complex 2 and oxygen atom transfer from complex 2 to PPh₃ were calculated and probable mechanisms for both reactions proposed.