E.s.r. studies of ion association. Part 6.—A study of atom transfer between potassium-2,5-di-t-butyl p-benzosemiquinone and 2,5-di-t-butyl p-benzoquinone

Abstract

It is argued that the electron spin resonance spectrum of an ion-pair simultaneously undergoing intramolecular cation exchange between equivalent conformations and intermolecular atom transfer with neutral parent molecules may fortuitously show a binomial intensity distribution even though both exchange processes may be going at rates of the order required to produce linewidth effects. Experiments with potassium-2,5-di-t-butyl p-benzosemiquinone illustrate the phenomenon. At room temperature the rate constant for the reaction TBPBSQ-potassium + TBPBQ ⇌ TBPBQ + potassium-TBPBSQ is estimated to be 6.43 × 10⁷ M^–1 s^–1.