Alkaline Hydrolysis of Triphenylsilane in Acetonitrile. A Comment on the Structure of the Transition State

Abstract

Previously, the influence of water on the kinetics(') and on the Arrhenius parameters (,) of the base catalysed hydrolysis of triphenylsilane in ACN(,) was investigated. The medium effect upon the activation energy was examined and the values for the transfer Gibbs function of the activated state were compared with the transfer parameters related to OH-. Therefrom, it was concluded that the structure of the activated state, in the rate determining step [lbl, was much more related to the reaction products than to the pentacovalent complex arising in equilibrium [la], which is its main constituent. According to Leffler and Hammond(3), the molar Gibbs function for XC can be formulated as a linear combination of the molar free energies of reactants and products, i.e. 6,Gxr = a 6,Gp t (1-a) 6&, where 8, refers to the transfer from the reference medium to the mixture. So,-301 -