Abstract
One-electron oxidations of L-ascorbic acid and its analogs or derivatives were investigated by electron spin resonance (ESR). ESR spectra were obtained from compounds not substituted at 3-hydroxyl group. Two types of spectra were observed when Ti3+-H2O2 system was used as the oxidizing agent. On the basis of the comparison of the ESR spectra obtained from the compounds examined with one another and their pH-profile, the radical structures and hyperfine couplings were determined. One type of spectrum corresponds to an anion radical and the other corresponds to a neutral species. Variation in line width and the finding that only an anion radical was detected when oxidizing reagents other than Ti3+-H2O2 system was used, were interpreted in terms of the complex formation of radicals with metal ions coexisting in the reaction system.
