Unifying the solution thermochemistry of molecules, radicals, and ions

A general cycle was developed that defines the thermodynamics for all of the homolytic and heterolytic cleavage reactions of a hydrocarbon, R-R\u2019, in solution. Only seven experimental parameters were needed in order to define the energetics for all 11 of the possible cleavage reactions of R-R\u2019. These parameters were the oxidation and reduction potentials of R-R\u2019, R\u2019, and R\u201d and the homolytic, R-R\u2019, bond energy. The utility of this approach was demonstrated for the case where R was an arylmethyl group and R\u2019 was hydrogen. The oxidation and reduction potentials of the arylmethyl radicals were measured by modulation voltammetry in acetonitrile, and the homolytic C-H bond energies of the corresponding hydrocarbons were measured by photoacoustic calorimetry. The cycle was also extended to a case where R-R\u2019 was a radical rather than a closed-shell molecule.NRC publication: Ye