Kinetic and mechanism of the oxidation of chromium(III) complex with anthranil-N,N-diacetic acid by periodate ion in acidic aqueous solutions

摘要

The kinetics of oxidation of [Cr-III(atda)(H2O)(2)] (atda = anthranil-N,N-diacetato) complex by IO (4) (-) was studied spectrophotometrically in aqueous solutions with pH range 2.20-3.34, 0.30 M ionic strength and in 20.0-40.0A degrees C temperature range. The rate law of the reaction exhibited saturation kinetics. Values of the rate constant for the electron transfer process, the equilibrium constant for dissociation of [Cr-III (atda)(H2O)(2)] to [Cr-III (atda) (H2O)OH](+) + H+ and the pre-equilibrium formation constant were calculated. The thermodynamic activation parameters are reported. It is proposed that electron transfer proceeds through an inner-sphere mechanism via coordination of the I-VII to chromium(III).