Kinetics and Mechanism of Oxidation of Ethylenediamine and Related Compounds by Diperiodatoargentate (III) Ion

摘要

The oxidation of ethylenediamine by diperiodatoargentate (Ilt) ion has be-en stud- ied by stopped-flow spectrophotometry. Kinetics of this reaction involves two steps. The first step is the cornplexation of silver (111) with the substrate and is over in about 10 Ms. This is followed by a redox reaction in the second step that occurs intramolecularly from the substrate to the silver (111) center, The rate of reduction of silver (111) species by ethylenediamine, ethanolamine, and 1,2-ethanediol were observed to be 1.2 X 101, I I X 102, and 0 14 dml mol-I s 1, respectively, at 20'C. The reaction rate shows an inverse dependence on 110, I and JOH I in the low concentration range (!51 X 10-1 mot dm-1). At higher JOH-1 (>I X la 3 Mot dm 1) the rate of reaction starts increasing and attains a limiting value at very high JOH 1. The rate of deamination of ethylenediamine is enhanced by its comptexation with silver (111). The Involvement of lAg "(H2'06) (H,O),] and lAgl"(H,10,) (OH),12- are suggested as the reactive silver (111) species kinetically in mild basic and basic conditions, respectively. C) 2000 John Wiley & Sons, Inc Int j Chem Kinet 32: 286-293, 2000