Probing the Reactivity of Hydroxyl Radicals toward Isolated Thymine Using Theoretical Calculations
Article first published online: 10 OCT 2013
Copyright © 2013 Wiley Periodicals, Inc.
International Journal of Quantum Chemistry
Volume 114, Issue 6, pages 367–374, 15 March 2014
How to Cite
How to cite this article: Int. J. Quantum Chem. 2014, 114, 367–374, DOI: 10.1002/qua.24567, , , .
- Issue published online: 5 FEB 2014
- Article first published online: 10 OCT 2013
- Manuscript Accepted: 16 SEP 2013
- Manuscript Revised: 30 AUG 2013
- Manuscript Received: 17 JUN 2013
- National Natural Science Foundation of China . Grant Number: 11025524 and 11161130520
- National Basic Research Program of China . Grant Number: 2010CB832903
- Natural Science Foundation of Guizhou Province of China . Grant Number: J20122141
- The Chinese Academy of Sciences (D.W.; Frontier of Novelty Program) . Grant Number: Y1515540U1
- DNA base;
- solvent effect
B3LYP and MP2 methods are used to study the hydroxylation and dehydrogenation of thymine at different sites in the presence of hydroxyl radicals (⋅OH). With a 6-311++G(d,p) level of description, the consistent results thermodynamically show that the relative free energy increases in the order of CM5 < N1 < C6 < N3 on the hydrogen abstraction. However, toward the hydroxylation, though the two methods give a similar trend that free energy barrier increases in the order of C6 < C5 < C4 < C2, they describe the reaction at C6 site in a different way: B3LYP calculation gives a barrierless pathway, whereas MP2 calculation gives a reactant complex with an energy of 19.5 kJ/mol and a pathway with a barrier energy of 64.9 kJ/mol. The calculated results are consistent with experimental data and the preference for the C5 site is due to the facility of ⋅OH in approaching the substrate. © 2013 Wiley Periodicals, Inc.