Theoretical Survey on Tautomerism of Thioguanine Tautomers by Polarisable Continuum Method (PCM)

Abstract

Computational calculations at B3LYP/CC-PVDZ level were employed in the study of tautomers of Thioguanine (TG) in the gas phase and selected solvents such as benzene , tetrahydrofuran (THF), methanol, Dimethyl sulfoxide (DMSO) and water using PCM model. All tautomers are optimized at this level. In addition, stability of the tautomers in different solvents shows interesting results. In the gas phase, benzene and THF, TG1 form is more stable than the other forms but in polarisable solvents (methanol, DMSO and water) TG5 is the most stabilized form. Variation of dipole moments and NBO charges on atoms in the solvents were studied.