A correlated ab initio quantum chemical study of the interaction of the Na+, Mg2+, Ca2+ and Zn2+ ions with the tautomers of cytosine in the presence of polar solvent

Abstract

The interactions of the metal ions Na⁺, Mg²⁺, Ca²⁺ and Zn²⁺ with cytosine have been investigated with inclusion of solvent effects. Computations have been performed at the density functional and Møller–Plesset levels of theory within the IEFPCM solvent model. It has been found that the inclusion of the solvent environment is essential for giving more biologically realistic results. Earlier gas-phase findings of the stabilisation of rare tautomeric forms by the metal ions have been reproduced, with the presence of the solvent further affecting the relative stabilities.