H proton intramolecular transformation in OH-OO-isoprene radicals

In this study, ab initio calculations have been performed to investigate the H proton intramolecular transformation in OH-OO -isoprene radicals. Geometry optimizations and transition states were performed using density functional theory at the UB3LYP/6–31+G∗∗ and M06-2X/6-311++G∗∗ level. It was found that the migration H atoms was all from the hydroxy-H in the predominant energetic route of 1-OH-2-OO -isoprene and 4-OH-3-OO -isoprene radicals with the energy barrier of 17.7 and 17.0 kcal/mol at the UB3LYP/6-31+G∗∗ level, respectively. The migration H atoms were all from the CH2 groups next to hydroxy of Z-1-OH-4-OO -isoprene and Z-4-OH-1-OO -isoprene radicals in the energetic predominant routes with the energy barrier of 14.9 and 25.9 kcal/mol at the UB3LYP/6-31+G∗∗ level, respectively, then the intermediates overcome 7.7 and 7.2 kcal/mol to react with O2 molecule to regenerate HO2. Graphical abstract

Source: Computational and Theoretical Chemistry - March 21, 2018 Category: Chemistry Source Type: research