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Spectroscopy
Volume 17, Issue 4, Pages 753-762
http://dx.doi.org/10.1155/2003/607917

Rationalisation of the activities of phenolic (vitamin E-type) antioxidants

Christopher J. Rhodes, Thuy T. Tran, Philip Denton, and Harry Morris

School of Pharmacy and Chemistry, Liverpool John Moores University, Byrom St., Liverpool, L3 3AF, UK

Copyright © 2003 Hindawi Publishing Corporation. 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

Using Transition-State Theory, experimental rate constants, determined over a range of temperatures, for reactions of vitamin E type antioxidants are analysed in terms of their enthalpies and entropies of activation. It is further shown that computational methods may be employed to calculate enthalpies and entropies, and hence Gibbs Free Energies, for the overall reactions. Within the Linear Free Energy Relationship (LFER) assumption, that the Gibbs Free Energy of activation is proportional to the overall Gibbs Free Energy change for the reaction, it is possible to rationalise, and even to predict, the relative contributions of enthalpy and entropy for reactions of interest, involving potential antioxidants.