Isomeric adduct stability in the addition of atomic radicals to toluene: H, O(3P), F and Cl

Abstract

In recent work we have found that, in the case of the OH addition to toluene, ipso addition may be important. Moreover, quite different values were calculated for several of the EPR coupling constants of the different adduct isomers, suggesting that electron paramagnetic resonance measurements could provide decisive information on the selectivity of the OH radical addition reaction to toluene. In this work, the reaction of the atomic radicals, H, O(³P), F and Cl with toluene has been studied using ab initio theoretical methods to compare the stability of the isomeric adducts and to predict their expected hyperfine coupling constants. Ipso addition is found to be favored only for fluorine, although the ipso and ortho isomers have very similar energies for oxygen and chlorine. Ipso adducts are expected to contribute nonnegligibly in all cases.