Kinetics of oxidation of glycine and related substrates by diperiodatoargentate (III)

The reactions of diperiodatoargentate(III) with glycine and related compounds have been examined. The monoperiodatosilver(III) species acts as an active oxidant in comparison to that of diperiodatosilver(III) species. These reactions consist of three kinetically distinguishable steps-induction period, complexation and oxidation. Complexation of these substrates takes place with a second order rate constant of (0.2-1.6)x10(4) dm(3) mol(-1) s(-1) whereas the redox process occurs at a rate of (0.3-6.0)x 10(2) dm(3) mol(-1) s(-1) except in case of cysteine with which these processes occurred by an order of magnitude faster. The rate of electron transfer from carboxylic acids to the silver(III) complex is observed to be several order of magnitude smaller in comparison to that of amino acids. Both the rate of complexation and electron transfer are influenced by the structure of the substrates. The aquated silver(III) species is found to be more reactive in comparison to the hydroxylated silver(III) species. (C) 1999 Elsevier Science Ltd. All rights reserved.