Kinetics and mechanism of the oxygen-transfer reaction between bis-(diethyldithiocarbamato)dioxomolybdenum(VI) and triphenylphosphine

Abstract

The kinetics of the oxygen-transfer reaction from [MoO₂(S₂CNEt₂)₂] to PPh₃ in acetonitrile solution have been monitored using stopped-flow techniques at temperatures between 15 and 45 °C. The rate law d[Mo^IV]/dt=k₂[Mo^VI][PPh₃], with k₂(25 °C)= 1.1 ± 0.3 dm³ mol^–1 s^–1, describes the kinetic data obtained, with activation parameters at 25 °C of ΔH^‡= 8.4 ± 0.5 kcal mol^–1 and ΔS^‡=–30 ± 1.6 cal K^–1 mol^–1.