THERMODYNAMICS FOR C-H BOND-BREAKING OF SOME AMPHIHYDRIC COMPOUNDS BY TRANSFER OF PROTONS, HYDRIDE IONS, H-ATOMS AND ELECTRONS

Carbenium ions, radicals, and carbanions can be generated by transfer of a hydride ion, hydrogen atom or proton from a R-H bond to an appropriate Lewis acid, radical or base. When all three of these reactive species are stable enough to be generated in solution a compound is referred to as ''amphihydric'' (e.g., triphenylmethane). Energetics for R-H cleavage in these ways are the most generally useful criteria for the stabilities of R(+), R(.), and R(-). In addition, their stabilities relative to each other can be established by electron transfer if redox potentials are reversible. Stabilities of R(+), R(.) and R(-) for several series of amphihydric compounds (e.g., 9-arylxanthenes, 2-aryl-1,3 dithianes) are reported as determined by the four methods referred to above. Relationships between these normally unrelated properties will be discussed.