Ultraviolet photoionization of the photosensitizers khellin and visnagin in aqueous solution and in micelles: One-photon ionization is a minor process

Sameh El-Gogary, Gottfried Grabner

    Veröffentlichungen: Beitrag in FachzeitschriftArtikelPeer Reviewed

    Abstract

    One-photon ionization, leading to formation of hydrated electrons and radical cations, has been proposed as a possible mechanism of action of some sensitizers in photobiology. In this contribution, we have investigated this proposal for the compounds khellin and visnagin, used in photomedical applications. Nanosecond transient absorption spectroscopy covering a wide range of laser pulse energies was employed to measure the formation of radical cations and hydrated electrons in aqueous solution and in cationic (CTAB) as well as anionic (SDS) micellar solutions. A model allowing for simultaneous one- and two-photon processes and fully accounting for the nonlinearity of the pulse energy dependence was used to simulate the data. The results did not support the hypothesis of a significant role of one-photon ionization, the upper limits of the quantum yields of radical cation formation being f <0.01 for visnagin and f <0.004 for khellin. ΠThe Royal Society of Chemistry and Owner Societies 2006.
    OriginalspracheEnglisch
    Seiten (von - bis)311-316
    Seitenumfang6
    FachzeitschriftPHOTOCHEMICAL & PHOTOBIOLOGICAL SCIENCES
    Jahrgang5
    Ausgabenummer3
    DOIs
    PublikationsstatusVeröffentlicht - 2006

    ÖFOS 2012

    • 106041 Strukturbiologie
    • 104021 Strukturchemie

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