Abstract
The present study compared the interactions among Na +, K +, Mg2+ and Ca2+, thymine and its tautomers in the gas and solvent phase, an interaction dependent upon the electronic construction of the tautomers. Three types of cation interaction with thymine and its tautomers were observed. In the first one, the metal cations interacted with a lone pair of nitrogen or oxygen of the tautomers. In the second type, there was an interaction among the cations, nitrogen and oxygen at the same time; the last one was that of cations with the electron density of thymine π-system, where the cations were perpendicular to the ring of thymine. The interaction of metals cation with tautomers was studied in the gas and solvent phases; a comparison was then made between interactions in two phases. The interaction energy for all complexes indicated the stability of complexes, an energy which was higher in Ca2+ and Mg2+ compared with Na+ and K+. Concerning K+ and Na+, the stability of all complexes of tautomers was greater than that of thymine complexes; however, the stability of certain Ca2+ and Mg2+ complexes was lower than the complexes of thymine.
GRAPHICAL ABSTRACT
Disclosure statement
No potential conflict of interest was reported by the authors.