A theoretical investigation of the energy and structure of ion–molecule pairs in polar solvents. Part 2. Methanediazonium cation in water

Abstract

MO theory at the CNDO/2 level of approximation was used to investigate the dissociation process of methane-diazonium ion in vacuo and in water. The dissociation in vacuo has also been studied by means of ab initio calculations. CH₃N₂⁺ in solution dissociates without formation of intermediates, unlike C₆H₅N₂⁺, which forms stable ion–molecule pairs. For both ion–molecules the dissociation energy is drastically reduced on going from gas phase to solution. Ab initio calculations for methanediazonium ion, in which polarization functions are included in the basis set, show that the open structure is still significantly more stable than the bridged ones.