Table of Contents
Research Letters in Inorganic Chemistry
Volume 2009, Article ID 314672, 5 pages
http://dx.doi.org/10.1155/2009/314672
Research Letter

Kinetic and Mechanistic Studies on the Reaction of DL-Methionine with [ ( H 2 O ) ( t a p ) 2 R u O R u ( t a p ) 2 ( H 2 O ) ] 2 + in Aqueous Medium at Physiological pH

1Department of Chemistry, The University of Burdwan, Burdwan, West Bengal 713104, India
2Department of Pediatrics, Burdwan Medical College, Burdwan, West Bengal 713104, India

Received 10 December 2008; Accepted 4 January 2009

Academic Editor: Wolgang Linert

Copyright © 2009 Tandra Das et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The reaction has been studied spectrophotometrically; the reaction shows two steps, both of which are dependent on ligand concentration and show a limiting nature. An associative interchange mechanism is proposed. Kinetic and activation parameters ( k 1 1 0 3 s 1 and k 2 1 0 5 s 1 ) and ( Δ H 1 = 1 3 . 8 ± 1 . 3 k J m o l 1 , Δ S 1 = 2 5 0 ± 4 J K 1 m o l 1 , Δ H 2 = 5 5 . 5 3 ± 1 . 5 k J m o l 1 , and Δ S 2 = 1 4 3 ± 5 J K 1 m o l 1 ) have been calculated. From the temperature dependence of the outer sphere association equilibrium constant, thermodynamic parameters ( Δ H 1 = 1 6 . 6 ± 2 . 3 k J m o l 1 and Δ S 1 = 9 5 ± 7 J K 1 m o l 1 ; Δ H 2 = 2 9 . 4 ± 3 . 2 k J m o l 1 and Δ S 2 = 1 2 8 ± 1 0 J K 1 m o l 1 ) have also been calculated.