Kinetics and mechanism of the oxidation of a ternary complex of cobalt(II) involving nitrilotriacetate and benzoate by periodate in acetate medium. Evidence for manganese(II) as a catalyst

Kinetics of the oxidation of [CoII(nta)(bz)(H2O)2]2- (nta = nitrilotriacetate and bz = benzoate) by periodate in acetate medium have been investigated spectrophotometrically at 580 nm under pseudo first order condition by taking large excess of [image omitted] over the 15.0-35.0C range at pH = 4.99 and I = 0.50 M. The kinetics in acetate medium obeyed the rate law: [image omitted] Also, the oxidation of [CoII(nta)(bz)(H2O)2]2- by periodate in the presence of Mn(II) as a catalyst was carried out. The rate of reaction increases as the concentration of Mn(II) increases. Initial cobalt(III) products were formed and slowly converted to final products, fitting an inner-sphere mechanism. The enthalpy and entropy of activation were measured using the transition state theory equation.