On the reaction of ground-state nitrogen atoms with bromomethyl radicals: A computational study

A computational study of the reaction of N(4S) with CH2Br radicals has been carried out. The reaction starts through the formation of a relatively stable intermediate which does not involve an energy barrier. The two most exothermic products are those resulting from the release of a bromine atom, H2C = N + Br and trans-HC = NH + Br. A kinetic study, within the framework of the statistical theories, shows that the most exothermic product, namely H2C = N + Br, is also the preferred product under kinetic control, whereas only minor fractions of HBrCN + H are predicted at all temperatures. Therefore, the mechanistic characteristics observed for the N(4S) + CH2Br reaction are very similar to the N(4S) + CH2Cl reaction, but quite different from those found in the case of N(4S) + CH2F, where the preferred channel corresponds to formation of HFCN through elimination of a hydrogen atom. The rate coefficient for the title reaction is estimated to be about 9 × 10−13 cm3 s−1 molecule−1 at 300 K, showing that should proceed with a high efficiency.