Simultaneous effect of nitrogen, trifluoromethyl and dimethylamino group on the radical trapping activity of diphenylamine: Aquantum chemical study

Abstract

To maximize the peroxyl radical trapping activity of diphenynlamine, the substituents such as N, NMe₂, and CF₃ are suggested to add to their phenolic rings. The reasonable combination of these substituents at the right position can reduce the bond strength of the N-H bond, but still keep the derivatives stable in air. By substituting N and CF₃ at the meta positions and NMe₂ at the para positions of both phenolic rings, the bond dissociation enthalpies of N-H calculated at B3P86/6-311G method are around 80.0 kcal/mol but ionization energies calculated at PM6 method are still high enough in the range of 187.9 to 189.0 kcal/mol, resulting in enhancing the radical trapping activity and preventing the one-electron oxidation. Potential energy surface of the reactions between CH₃OO radical with the selected diphenylamine derivatives was established via the hydrogen atom transfer process.