Reactivity of Aliphatic and Aromatic Nitrocompounds in the Triplet State with Respect to Amines

Reactions of photochemical hydrogen transfer are modeled by means of quantum chemistry. Nitromethane and nitrobenzene in the triplet state in combination with ammonia, methylamine, or dimethylamine as hydrogen donors are studied. The structures of reaction complexes of the original materials, the transitional states and reaction products, the activation energies of the reactions, and changes in the standard enthalpies of the reactions are determined. The profiles of the potential energy surfaces of certain reactions are modeled. It is established that all profiles are very smooth, and the activation energies are low. The distribution of electron density in complexes is studied using Bader's theory of atoms in molecules. All complexes have a characteristic ring structure that can be considered a source of additional interaction during a reaction. It is suggested that such a structure is responsible for the low activation energies of the reaction.