Kinetics of Electron Transfer from Cyclic Ketones to Ni(IV) Periodate Complex in Aqueous Alkaline Medium

Abstract

Abstract The kinetics of electron transfer from cyclic ketones (represented by (S)) to Ni(IV) periodate complexes has been studied in aqueous alkaline medium. The kinetics exhibit a pseudo-first-order disappearance of Ni(IV) periodate complexes when the [substrate] is present in excess. The pseudo-first-order rate constants, kobs, were linearly dependent on [S] and the order in [S] were found to be unity. The rate of the reaction increased with the increase in [OH−], however the rates were retarded with the increase in [periodate]. Salt and solvent effect studies indicate that the reaction is of ion-dipole type. A suitable mechanism involving slow adduct formation between enol and oxidant, and its decomposition in a fast step have been suggested. A rate law consistent with the proposed mechanism has also been derived. The products of oxidation were identified as corresponding decarboxylic acids.