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Reaction force analysis of the effect of Mg(II) on the 1,3 intramolecular hydrogen transfer in thymine
Elizabeth Rincón1, Pablo Jaque, Alejandro Toro-Labbé
1QTC, Departamento de Química Física, Facultad de Química, Pontificia Universidad Católica de Chile, Casilla 306, Correo 22, Santiago, Chile.
Abstract:
The 1,3 intramolecular hydrogen transfer reaction in free thymine and in Mg(II)-thymine have been studied at the density functional theory level. The mechanism of intramolecular proton transfer in these systems emerges from the analysis of the reaction force profile along the reaction path; it is rationalized in terms of structural and electronic reorganizations that take place during the chemical transformation. Results show that the presence of Mg(II) monocoordinated to thymine activates the hydrogenic motion by inducing structural and electronic changes in the molecular backbone. In the metallic complex, it is found that the hydrogen transfer is followed by a relaxation process that facilitates the metal cation migration to form a bicoordinated complex.
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