Effect of the Solvent and Substituent on Tautomeric Preferences of Amine-Adenine Tautomers.

Adenine is one of the basic molecules of life; it is also an important building block in the synthesis of new pharmaceuticals, electrochemical (bio)sensors, or self-assembling molecular materials. Therefore, it is important to know the effects of the solvent and substituent on the electronic structure of adenine tautomers and their stability. The four most stable adenine amino tautomers (9H, 7H, 3H, and 1H), modified by substitution (C2- or C8-) of electron-withdrawing NO and electron-donating NH groups, are studied theoretically in the gas phase and in solvents of different polarities (1 ≤ ε < 109).