Transient Phenomena in the Pulse Radiolysis of Retinyl Polyenes. 3. Radical Cations1,2

Article abstract of DOI:10.1021/j100269a038

Results are presented concerning transient absorption phenomena observed upon pulse radiolysis of several retinyl polyenes at submillimolar concentrations in acetone, n-hexane, and 1,2-dichloroethane under conditions favorable for radical cation formation.Oxygen insensitive, the polyene radical cations are characterized by intense absorption maxima (575-635 nm) with locations that show little or no dependence on functional groups.In acetone, they undergo decay predominantly by first-order kinetics with lifetimes 4-11 μs.The biomolecular rate constants for radical cation quenching by water, triethylamine, and bromide ion in acetone are in the ranges (0.8-2) X 10⁵, (0.3-2) X 10⁸, and (3-5) X 10¹⁰ M^-1 s^-1, respectively.