Bond dissociation enthalpies of polyphenols: the importance of cooperative effects.
The hydrogen-oxygen bond dissociation energies of 3,5-di-tert-butylcatechol, 2,5-di-tert-pentylhydroquinone, propyl gallate, and octyl gallate, which represent model compounds of three important classes of naturally occurring antioxidants, have been measured by an EPR equilibration technique, and the factors determining their values have been clarified. The excellent antioxidant activity of the these polyphenols is largely due to the stabilization of the aroxyl radical due to the formation of an intramolecular hydrogen bond.
Lucarini
Marco
M
Dipartimento di Chimica Organica A. Mangini, Università di Bologna, Via S. Donato 15, I-40127 Bologna, Italy.
Mugnaini
Veronica
V
Pedulli
Gian Franco
GF
D004578:Electron Spin Resonance Spectroscopy; D005419:Flavonoids; D010636:Phenols / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D059808:Polyphenols; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics
D005419:Flavonoids; D010636:Phenols; D011108:Polymers; D059808:Polyphenols