Kinetics of formation of a pi-allyl palladium complex on the basis of 2-methyl-2-propanol

The kinetics of formation of a pi -allyl palladium complex by the reaction of 2-methyl-2-propanol with palladium(II) tetraaqua complex in perchloric a cid medium at alcohol, palladium(II), and perchloric acid concentrations of 0.05-1.1, (1.5-6) x 10(-3), and 0.15-0.56 M, respectively, were studied. T he reaction rate is directly related to acid concentration and does not dep end on the initial concentration of the complex [Pd(H2O)(4)](ClO4)(2); the dependence of the rate on alcohol concentration is described by the Michael is-Menten equation. The activation parameters E-ap(a) 96.1+/-4 kJ mol(-1) a nd DeltaS(not equal) 10.0+/-4 kJ mol(-1) K-1 (T 55 degreesC) were obtained. Addition of chloride ions considerably slows down the reaction but has no effect on the yield of the pi -allyl complex. A mechanism is proposed, invo lving 2-methylpropene formation.