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DOI: 10.1039/A903511G (Paper) Reference Section for: J. Chem. Soc., Perkin Trans. 2, 1999, 2133-2139

Kinetics and mechanism of the hydrogen peroxide oxidation of a pentafluorophenyl-substituted iron(III) porphyrin[hair space]†

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Ian D. Cunningham, Timothy N. Danks, Keith T. A. O’Connell and Peter W. Scott

Abstract

Kinetic analysis of the (F20TPP)FeCl-catalysed H2O2 oxidation of 3-hydroxy-2-(trans-4-tert-butylcyclohexyl)methylnaphtho-1,4-quinone is consistent with rapid reaction of the organic substrate with an oxoperferryl intermediate [(F20TPP˙+)FeIV[double bond, length half m-dash]O] formed in the first and rate-limiting step. A second-order rate constant for oxidation of the catalyst of 22 ± 5 dm3 mol–1 s–1 is found, a value lower than previously reported. In the absence of the organic substrate, H2O2 oxidises the catalyst to an oxoferryl species (F20TPP)FeIV[double bond, length half m-dash]O, probably via the oxoperferryl species. This oxoferryl compound is itself bleached by H2O2 with a second-order rate constant of 0.081 ± 0.004 dm3 mol–1 s–1 probably involving oxidation of the porphyrin ring.

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