Estimation of bond dissociation Gibbs energies for carbon–halogen bonds in anion radicals of some aryl halides and substituted benzyl halides

Abstract

A thermochemical cycle incorporating the standard potential EoRX/RX˙–. of aryl halides and m- and p-substituted benzyl halides RX, the standard potential EoX˙–/X– of the halide ion X– and the bond dissociation Gibbs energy ΔGoBDE(RX) of RX is used to determine the bond dissociation Gibbs energy ΔGoBDE(RX˙–) of the carbon–halogen bond in some anion radicals RX˙–. The values of EoRX/RX˙– are not directly measurable for most benzylic substrates but can be approximated by the standard potentials for the corresponding compounds in which the CH2X group is replaced by an H atom. The calculations are compared with experimental results and similar calculations published recently.