In this paper, we show the reaction of a hydroxyl, phenyl and phenoxy radicals with DNA base pairs by the density functional theory (DFT) calculations. The in°uence of solvation on the mechanism is also presented by the same DFT calculations under the continuum solvation model. The results showed that hydroxyl, phenyl and phenoxy radicals increase the length of the nearest hydrogen bond of adjacent DNA base pair which is accompanied by decrease in the length of furthest hydrogen bond of DNA base pair. Also, hydroxyl, phenyl and phenoxy radicals in°uenced the dihedral angle between DNA base pairs. According to the results, hydrogen bond lengths between AT and GC base pairs in water solvent are longer than vacuum. All of presented radicals in°uenced the structure and geometry of AT and GC base pairs, but phenoxy radical showed more in°uence on geometry and electronic properties of DNA base pairs compared with the phenyl and hydroxyl radicals.
