Abstract
Melatonin is an excellent free radical scavenger, reacting with ferf-butoxyl and cumyloxyl radicals with rate constants of 3.4 × 107 and 6.7 × 107 M−1s−1, respectively. Reaction with benzophenone triplet occurs with a near-diffusion-controlled rate constant of 7.6 × 109 M−1s−1 in acetonitrile and probably involves charge transfer. When the radical pair formed by reaction of benzophenone triplet and melatonin is sequestered in a micelle, it is subject to extensive magnetic field effects that can be readily interpreted by the radical pair model.