STABILITIES OF SOME 2-(PARA-SUBSTITUTED-PHENYL)4,4,5,5-TETRAMETHYL-1,3-DIOXOLANES RELATIVE TO THEIR CONJUGATE DIOXOLENIUM IONS, RADICALS AND CARBANIONS AS DETERMINED BY THERMODYNAMICS FOR HYDRIDE AND ELECTRON-TRANSFER IN SOLUTION

A calorimetric method is described for the determination of the hydride affinities, Delta H-H-(R(+)) of seven dioxolenium ions from the title compounds and also tropylium, trityl and 9-phenyl xanthylium cations by hydride transfer to the carbocations from BH3CN-. Cyclic voltammetric methods yield free energies for reduction of the cations to the conjugate radicals and to the carbanions. The Delta H-H-(R(+)) values correlate well with the first reduction potentials of the cations.