Correlated Ab Initio QuantumChemical Study of the Interaction of the Na, Mg2, Ca2, and Zn2⊉ with the Tautomers ofCytosine.

The interaction of the metal ions Na, Mg2, Ca2, and Zn2숫 cytosine havebeen reinvestigated at the density functional, Møller–Plesset,and coupled cluster levels of theory, including hitherto unstudiedtautomeric forms. It has been found that the interaction of the metalion has a varying and often significant effect on the stabilitiesof the various tautomers, in some cases making most stable rare tautomericforms. The results have been analyzed with respect to method and roleof ion in binding, and confirm that, as has been found for the basecytosine tautomers, B3LYP does not give energetics consistent withhighly accurate post-SCF methods for their interaction with thesemetal ions. [ABSTRACT FROM AUTHOR]