Theoretical study of the hydrogen abstraction from vitamin-E analogues. The usefulness of DFT descriptors

The activation and reaction energies governing hydrogen atom transfer between α-tocopherol analogues and methylperoxyl radical were determined using the B3LYP/6-311++G(d,p) method. An a priori qualitative estimation of the charge transfer involved in the formation process of the two-fragment reaction between α-tocopherol-like molecules and the methylperoxyl radical was used as a predictive tool to determine antioxidant activity. Consistency between the energetic data and reactivity criterion was nicely reached indicating that the electronic nature of the substituents in the heterocyclic ring in α-tocopherol-like molecules strongly influences the activation and reaction energies.