Effects of the Ionization in the Tautomerism of Uracil: A Reaction Electronic Flux Perspective

Lamsabhi, AM; Gutierrez-Oliva, S; Mó O.; Toro-Labbe, A; Yañez M.

Keywords: tautomerism, hydrogen transfer, uracil, electronic reaction flux, Density functional theory (DFT), acidity and basicity


The one-step tautomerization processes of uracil and its radical cation and radical anion have been investigated in the light of the reaction force and reaction electronic flux (REF) formalisms. The relative energies of the different tautomers as well as the corresponding tautomerization barriers have been obtained through the use of the G4 high-level ab initio method and by means of B3LYP/6-3111G(3df,2p)//B3LYP/6-3111G(d, p) calculations. Systematically, the enol radical cations are more stable in relative terms than the neutral, due to the higher ionization energy of the diketo forms with respect to the enolic ones. Conversely, the enol radical anions, with the only exception of the 2-keto-N1 anion, are found to be less stable than the neutral. The effects of the ionization are also sizable on the tautomerization barriers although this effect also depends on the particular tautomerization process. The reaction force analysis shows that all reactions are mainly activated through structural rearrangements that initiate the electronic activity. This electronic activity is monitored along the reaction coordinate through the REF that obeys a delicate balance between the acid and basic character of the atoms involved in the hydrogen transfer.

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Título según WOS: Effects of the Ionization in the Tautomerism of Uracil: A Reaction Electronic Flux Perspective
Título según SCOPUS: Effects of the ionization in the tautomerism of uracil: A reaction electronic flux perspective
Título de la Revista: Journal of Computational Chemistry
Volumen: 36
Número: 28
Editorial: John Wiley and Sons Inc.
Fecha de publicación: 2015
Página de inicio: 2135
Página final: 2145
Idioma: English