A new method to study antioxidant capability: hydrogen transfer from phenols to a prefluorescent nitroxide.
[reaction: see text]. Rate constants for hydrogen abstraction from phenols by a prefluorescent-TEMPO probe are reported. The nitroxide is employed as a potential model of peroxyl radicals. The probe works by nitroxide suppression of the fluorescence of the chromophore. The fluorescence is restored when the nitroxide abstracts a hydrogen atom to produce the diamagnetic hydroxylamine. The phenols studied in this project exhibited rate constants between 0.003 and 0.2 M(-1) s(-1). A deuterium isotope effect of 10 for TROLOX confirms that the mechanism is dominated by hydrogen transfer.
Department of Chemistry, University of Ottawa, Ottawa, Canada K1N 6N5.
Carolina
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Aliaga
Alexis
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Aspée
J C
JC
Scaiano