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DFT Calculations of Isotropic Coupling Constants of Phenoxyl and Aroxyl Radicals

Wolf Bors ; Institut fur Strahlenbiologie, GSF Research Center, D-85764 Neuherberg, Germany
Christa Michel ; Institut fur Strahlenbiologie, GSF Research Center, D-85764 Neuherberg, Germany
Kurt Stettmaier ; Institut fur Strahlenbiologie, GSF Research Center, D-85764 Neuherberg, Germany
Snježana P. Kazazić ; Ruđer Bošković Institut, P. O. Box 180, HR-10002 Zagreb, Croatia
Leo Klasinc ; Ruđer Bošković Institut, P. O. Box 180, HR-10002 Zagreb, Croatia

Sažetak

Hybrid density-functional calculations were carried out to corroborate the identity of phenoxyl radicals observed by EPR spectroscopy after oxidation of selected mono- and polyphenols with horseradish peroxidase/hydrogen peroxide or after alkaline autoxidation. Whereas quantitative correlations of experimental and theoretical coupling constants were less satisfactory, we could confirm formation of a bi-radical after initial oxidation of 2,4,6-trimethylphenol, the mesomeric structures of gallate ester aroxyl radicals and identify the radical site of a model gallotannin, hamamelitannin.

Ključne riječi

epr spectroscopy; coupling constants measurement; DFT calculation; polyphenols; antioxidant activity; phenoxyl and aroxyl radicals by phenol oxidation

Hrčak ID:

131757

URI

https://hrcak.srce.hr/131757

Datum izdavanja:

4.11.2002.

Posjeta: 955 *