Reactions of Hydrogen Peroxide with Metal Complexes. 5.¹ Mechanism of the Peroxo Complex Formation of (Nitrilotriacetato)dioxovanadate(V) As Studied by a High-Pressure Stopped-Flow Technique

A high-pressure stopped-flow apparatus has been exploited which enables us to follow reactions with a half-life longer than 0.1 s under pressure up to 1600 kg cm^-2. The rate for the formation of the peroxo complex of (nitrilotriacetato)dioxovanadate(V) (VO₂(nta)^2-) is expressed as d[VO(O₂)(nta)^2-]/dt = (k₁ + k₂[H⁺])[VO₂(nta)^2-] [H₂O₂], where k₁ = 7.05 m^-1 s^-1, k₂ = 1.46 X 104 m^-2 s^-1 at 25 °C and I = 1.05 m at atmospheric pressure and the volumes of activation for the k₁ and k₂ paths are -3.4 ± 0.5 and 1.5 ± 0.5 cm³ mol^-1, respectively. An associative mechanism is most probably operative.