Modeling the photoreduction of amines by the triplet nitromethane

Photoreduction of ammonia, methylavine and phenylamine by the triplet nitromethane has been investigated. Using uB3LYP/6-311g* method the geometry of the transition states, pre- and post-complexes was established. The mechanism of photoreduction is quite simple: it is the hydrogen atom abstraction. The N-H-bond of amine breaks and H-atom passes to the nitrocompound. This reaction yields two radicals. Calculated activation energy of the reaction between nitromethane and ammonia is of 3.17 kcal∙mol^-1. This one is much lower comparing to the reported earlier by us. The EOM-CCSD/cc-pVDZ method predicts activation energy of 2.57 kcal∙mol^-1. The next examined reaction is the reaction between the triplet nitromethane and methylamine. The mechanism is the same. Calculated activation energy is of 1.17 kcal∙mol^-1. Due to the methyl group presence it is the energy drop relatively to the first reaction. Some pictures of the electron density are included in the article. Comparing the radicals the phenylamine with nitromethane has been implemented. Calculated activation energy is of 1.51 kcal∙mol^-1. Hence phenyl group enhances the activation threshold of the proton abstraction. The reaction mechanism is the same hydrogen atom abstraction.