BOND-DISSOCIATION ENERGIES IN DMSO RELATED TO THE GAS-PHASE

Estimates have been made of the homolytic bond dissociation energies (BDEs) for (a) the benzylic or allylic H-C bonds in 14 hydrocarbons, (b) the acidic H-C bonds in 12 hydrocarbons containing one or more heteroatoms, and (c) the H-N bonds in five nitrogen acids as well as thiophenol and phenol. For the 18 compounds where literature gas-phase values were available, agreement to within +/- 2 kcal/mol was observed for all but three (Ph3CH, PhNH2, and PhOH). For Ph3CH and PhNH2, the literature values were shown to be in error. For the BDEs of the acidic H-A bonds in 17 compounds, error limits of +/- 2 kcal/mol, or better, were established from BDE estimates made for three or more derivatives in which remote substituents were placed on the benzene ring of the parent compound. In all, the BDEs of the acidic H-A bonds of 32 compounds have been established to +/- 2 kcal/mol or better.