γ-Radiation-Oxidation of Polycyclic Aromatic Hydrocarbons: Involvement of Singlet Oxygen

Article abstract of DOI:10.1021/ja00536a021

Oxidation of organic compounds in the presence of high-energy radiation is generally understood in terms of organic free-radical mechanisms.We investigated the chemistry of certain polycyclic aromatic hydrocarbons in oxygenated solutions submitted to γ-radiation from a cobalt-60 source in an effort t identifity and study other pathways in radiation-oxidation.Products obtained could be explained either through singlet oxygen (¹O2) production, through superoxide (O2^-.) production, or through a cation radical mediated reaction with O2.Quenching experiments clearly established singlet oxygen as the intermediate involved.The oxidation products varied markedly depending on the starting compound.This resulted because the primary endoperoxide adducts were subject to radiation-induced decomposition both by retrograde O2 expulsion and by breakdown to quinones.It was also found that certain common ¹O2 quenchers were ineffective in the radiation environment because of decomposition.