BOND DISSOCIATION ENTHALPY OF PHENOLIC ANTIOXIDANTS
 
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Pol. J. Food Nutr. Sci. 2003;53(Special issue 2s):129–135
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ABSTRACT
Homolytic bond dissociation enthalpies (BDEs) for O-H bonds in selected phenols have been theoreti cally calculated using density functional theory at the B3LYP/6-311G(d,p) and B3LYP/pp-cpTZ levels of theory. It was found that the B3LYP method is generally reliable for the prediction of absolute BDEs. This method works well for the prediction of substituent effects on BDEs. The deviations from experimental values are generally within 2-3 kcal/mol. The stability of phenoxyl radicals is largely affected by substituents and by internal hydrogen bonding. It was shown that, in particular, electron-donating substituents have large stabilizing effects on phenoxyl radicals. The application of the method for the prediction of the BDEs in polyhydroxyphenols is illustrated and discussed.
ISSN:1230-0322