Arylperoxyl Radicals. Formation, Absorption Spectra, and Reactivity in Aqueous Alcohol Solutions

Article abstract of DOI:10.1021/j100001a041

Aryl radicals (phenyl, 4-biphenylyl, 2-naphthyl, 1-naphthyl, and 9-phenanthryl) were produced by the reaction of the corresponding aryl bromide with solvated electrons and reacted rapidly with oxygen to produce the arylperoxyl radicals.These radicals exhibit optical absorptions in the visible range, with λ_max at 470, 550, 575, 650, and 700 nm, respectively.Arylperoxyl radicals react with 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate ion) (ABTS), chlorpromazine, and 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox C) by one-electron oxidation.The rate constants k for these reactions, determined from the rate of formation of the one-electron oxidation products as a function of substrate concentration, vary between 4 * 10⁶ and 2 * 10⁹ L mol^-1 s^-1 and increase in the order phenyl-, 4-biphenylyl-, 2-naphthyl-, 2-naphthyl-, and 9-phenanthrylperoxyl, the same order as the absorption peaks of these radicals.Good correlation was found between log k and the energy of the absorption peak.