Hydride affinities of arylcarbenium ions and iminium ions in dimethyl sulfoxide and acetonitrile

Free energy data for C-H heterolysis to carbenium ion and hydride in solution was obtained for a series of compounds using a new thermodynamic cycle based on gas-phase C-H bond dissociation enthalpy (BDE). The BDE of the H-R bond in the gas phase was used to calculate the Gibbs free energy for the homolytic cleavage of the bond in solution. Dimethyl sulfoxide and MeCN data for hydride transfer was also compared.