A theoretical investigation on the energy and structure of ion–molecule pairs in polar solvents. Part 1. Benzenediazonium cation in water
Molecular-orbital theory at the CNDO/2 level of approximation has been used to investigate the stability and structure of ion–molecule pairs in polar solvents. Benzenediazonium cation in water was chosen as a model system. The energy of the solute–solvent supermolecule was calculated as a function of the phenyl–nitrogen distance and the position of the water molecule in the first shell of solvation. The results are in favour of the existence of stable ion–molecule pairs and strongly support the mechanism which has been proposed for the dediazoniation of 2,4,6-trimethylbenzenediazonium ion in 2,2,2-trifluoroethanol on the basis of kinetic data.