Understanding hydrogenation of the adenine‐thymine base pairs and their anions: A density functional study

Abstract The B3LYP/DZP++ approach has been used to investigate the properties of hydrogenated radicals and anions of adenine‐thymine (A‐T) base pairs. Our calculations show that the hydrogenated radicals and anions have relatively high stabilities compared with the single adenine and thymine base. The conformations and hydrogen‐bond interactions of A‐T base pairs have obviously changed once the hydrogen atoms attached to the A‐T base pairs and their anion. As for the hydrogenated A‐T radicals, all of them exhibit relatively high electron affinities and different hydrogenation properties with respect to their components. The process of the bond formations of (C6)‐H (adenine) and (C6)‐H (thymine) are the most favorable in energetics. The two hydrogenation channels have the reaction Gibbs free energies (ΔG°) of −51.8 and −54.2 kcal mol −1 , respectively. Also, the calculations on the basis of CPCM model imply that the solvent effect plays an important role in the electron attachment and hydrogenation reactions, and can stabilize the hydrogenated A‐T anions. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012