Thermodynamic fitness of an RuIII(EDTA)/RuV=O(EDTA) couple in the oxygen atom transfer reactions

Taqui Khan, M. M. ; Prakash Rao, A. ; Samad, S. A. ; Chatterjee, Debabrata ; Bhatt, S. D. ; Merchant, R. R. (1990) Thermodynamic fitness of an RuIII(EDTA)/RuV=O(EDTA) couple in the oxygen atom transfer reactions Proceedings of the Indian Academy of Sciences - Chemical Sciences, 102 (3). pp. 231-237. ISSN 0253-4134

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Official URL: http://www.ias.ac.in/j_archive/chemsci/102/4/231-2...

Related URL: http://dx.doi.org/10.1007/BF02841937

Abstract

The complex [RuIII(EDTA-H)(H2O)]1 (EDTA-H = protonated ethylenediaminetetraacetic acid) catalyzes the epoxidation of cyclohexene and the oxidation of PPh3 to OPPh3 with molecular oxygen or NaOC1 as the oxidant. In both the cases, the active catalytic species is the [Ruv=O(EDTA)] ion 2̲ characterized by elemental analyses, UV-vis, infrared spectra and cyclic voltammograms. When oxygen is used as an oxidant in the reaction, oxidation of the substrates proceeds through a μ-peroxo-Ru(IV) intermediate [RusiIV(EDTA)(S)]2 O2−23̲ (S=olefin, PPh3) which undergoes a fast homolytic cleavage of the O-O bond to form [Ruv=O(EDTA)(S)]4̲ and a rate determining transfer of O atom to S to form SO and1. The cleavage of the O-O bond in 3 and O-atom transfer to S proceed in a concerted step. With NaOCl as an oxidant (excess), oxidation of 1̲ to 2̲ proceeds through a unimolecular decomposition of the [RuIII(EDTA)(OCl)]2− intermediate. The transfer of the O-atom from 2̲ to S proceeds by an associative (Ia) pathway involving a concerted cleavage of the Ru=O bond and formation of an SO bond. The free energy (ΔG) values for various steps are computed and the thermodynamic fitness of 2̲ as an oxidant discussed.

Item Type:Article
Source:Copyright of this article belongs to Indian Academy of Sciences.
Keywords:Thermodynamic Fitness; RuIII(EDTA)/Ruv=O(EDTA) Couple; Oxygen Atom Transfer Reactions
ID Code:57803
Deposited On:30 Aug 2011 10:30
Last Modified:18 May 2016 09:04

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