Hydroperoxyl Radicals (HOO. ): Vitamin E Regeneration and H-Bond Effects on the Hydrogen Atom Transfer

Jakub Cedrowski; Grzegorz Litwinienko; Andrea Baschieri; Riccardo Amorati

doi:10.1002/chem.201603722

Hydroperoxyl Radicals (HOO^. ): Vitamin E Regeneration and H-Bond Effects on the Hydrogen Atom Transfer

Chemistry. 2016 Nov 7;22(46):16441-16445. doi: 10.1002/chem.201603722. Epub 2016 Oct 6.

Authors

Jakub Cedrowski¹, Grzegorz Litwinienko², Andrea Baschieri³, Riccardo Amorati⁴

Affiliations

¹ Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093, Warsaw, Poland.
² Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093, Warsaw, Poland. litwin@chem.uw.edu.pl.
³ Department of Chemistry "G. Ciamician", University of Bologna, Via S. Giacomo 11, 40126, Bologna, Italy.
⁴ Department of Chemistry "G. Ciamician", University of Bologna, Via S. Giacomo 11, 40126, Bologna, Italy. riccardo.amorati@unibo.it.

PMID: 27709712
DOI: 10.1002/chem.201603722

Abstract

Hydroperoxyl (HOO^. ) and alkylperoxyl (ROO^. ) radicals show a different behavior in H-atom-transfer processes. Both radicals react with an analogue of α-tocopherol (TOH), but HOO^. , unlike ROO^. , is able to regenerate TOH by a fast H-atom transfer: TO^. +HOO^. →TOH+O₂ . The kinetic solvent effect on the H-atom transfer from TOH to HOO^. is much stronger than that observed for ROO^. because noncovalent interactions with polar solvents (Solv⋅⋅⋅HOO^. ) destabilize the transition state.

Keywords: hydrogen atom transfer; hydroperoxyl radicals; reactive oxygen species; solvent effects; tocopherol.