Reactions of the Hydrated Electron with Pyrene in Lipid Bilayer Vesicles

Pyrene and some pyrene derivatives were solubilized in bilayer vesicles of lecithin and the rates of reaction with the hydrated electron investigated. The concentration of the vesicles was 1.3 · 10−7 M, that of pyrene 10−6–10−4 M. The rate constant decreases with increasing pyrene concentration. This effect is explained by the highly inhomogeneous distribution of the pyrene molecules in the solutions. Only those pyrene molecules are reactive that reside close to the outer surface of the vesicles. The anions of pyrene formed disappear in a second order process. It is concluded that the anions are rapidly detached from their vesicular carriers and react with each other in the aqueous phase. Fluorescence, light scattering and electron microscopic investigations were also carried out to obtain information about the properties of the vesicles used.