Oxidation of Ru(III)‐Bound Thiocyanate with Peroxomonosulfate: Kinetic and Mechanistic Studies. Issue 3 (29th December 2015)

• Record Type: Journal Article
• Authors: Sarkar, Papiya; Chatterjee, Debabrata
• Is Part Of: International journal of chemical kinetics. Volume 48:Issue 3(2016)
• Page Start: 117
• Page End: 123
• Publication Date: 2015-12-29
• Subjects: Chemical kinetics -- Periodicals; 541.394
• DOI: 10.1002/kin.20976
• Languages: English
• ISSNs: 0538-8066

Abstract

ABSTRACT: The reaction of [Ru III (edta)(SCN)] 2− (edta 4− = ethylenediaminetetraacetate; SCN − = thiocyanate ion) with the peroxomonosulfate ion (HSO5 − ) has been studied by using stopped‐flow and rapid scan spectrophotometry as a function of [Ru III (edta)], [HSO5 − ], and temperature (15–30ºC) at constant pH 6.2 (phosphate buffer). Spectral analyses and kinetic data are suggestive of a pathway in which HSO5 − effects the oxidation of the coordinated SCN − by its direct attack at the S‐atom (of SCN − ) coordinated to the Ru III (edta). The high negative value of entropy of activation (Δ S ≠ = −90 ± 6 J mol −1 deg −1 ) is consistent with the values reported for the oxygen atom transfer process involving heterolytic cleavage of the O‐O bond in HSO5 − . Formation of SO4 2−, SO3 2−, and OCN − was identified as oxidation products in ESI‐MS experiments. A detailed mechanism in agreement with the spectral and kinetic data is presented.