“…The following results have been obtained at room temperature: k2 -1.2 X 1010 M^-s"1 and k3 =* 7.8 X 104 s-1 for benzophenone radical anion (BP*-) in water containing 2.5 M fert-butyl alcohol. 205 The rather high values k2 ~1010 M^-s"1 and k3 = 5 X 109-10u M^-s"1 indicate that the acid-base equilibrium is established very rapidly. Linear correlations have been found between the pK& of radicals and the Hammett and Taft constants,28 redox potentials of ketones, aldehydes, and quinones (for ketyl and semiquinone radicals),198,206 and the difference in the rr-electronic energies of the acid and basic forms of conjugated radicals.207 There is promise in the quantum-chemical calculation of radical affinity for proton (PA).…”