Ultrafast Photoinduced Electron Transfer in Viologen-Linked BODIPY Dyes

Authors

  • Dr. Denis Frath,

    1. Laboratoire de Chimie Organique et Spectroscopies Avancées, ICPEES, UMR 7515 au CNRS, Ecole Européene de Chimie, Polymère, et Matériaux, 25 rue Becquerel, 67087 Strasbourg Cedex (France), Fax: (+33) 3-68-85-26-89 http://icpees.unistra.fr/lcosa/
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  • Dr. James E. Yarnell,

    1. Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio, 43403 (USA)
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  • Dr. Gilles Ulrich,

    1. Laboratoire de Chimie Organique et Spectroscopies Avancées, ICPEES, UMR 7515 au CNRS, Ecole Européene de Chimie, Polymère, et Matériaux, 25 rue Becquerel, 67087 Strasbourg Cedex (France), Fax: (+33) 3-68-85-26-89 http://icpees.unistra.fr/lcosa/
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  • Prof. Felix N. Castellano,

    Corresponding author
    1. Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio, 43403 (USA)
    • Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio, 43403 (USA)
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  • Dr. Raymond Ziessel

    Corresponding author
    1. Laboratoire de Chimie Organique et Spectroscopies Avancées, ICPEES, UMR 7515 au CNRS, Ecole Européene de Chimie, Polymère, et Matériaux, 25 rue Becquerel, 67087 Strasbourg Cedex (France), Fax: (+33) 3-68-85-26-89 http://icpees.unistra.fr/lcosa/
    • Laboratoire de Chimie Organique et Spectroscopies Avancées, ICPEES, UMR 7515 au CNRS, Ecole Européene de Chimie, Polymère, et Matériaux, 25 rue Becquerel, 67087 Strasbourg Cedex (France), Fax: (+33) 3-68-85-26-89 http://icpees.unistra.fr/lcosa/
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Abstract

New boron-dipyrromethene (BODIPY) dyes linked to viologen are prepared and their photophysical and electrochemical properties are investigated. Both synthesized molecules have similar electronic absorption spectra with the absorption maximum localized at 517 and 501 nm for dye 1 and dye 2, respectively. They exhibit well-defined redox behavior, highlighting the presence of BODIPY and viologen subunits, with little perturbation of the redox potential of both subunits with respect to the parent compounds. Both dyes are heavily quenched by photoinduced electron transfer from the BODIPY to the viologen subunit. The transient absorption technique demonstrates that dye 2 forms the viologen radical within a timeframe of 7.1 ps, and that the charge-separated species has a lifetime of 59 ps. Sustained irradiation of dye 2 in the presence of a tertiary amine allows for the accumulation of BODIPY–methyl-4,4′-bipyridinium (BODIPY–MV+), as observed by its characteristic absorption at 396 and 603 nm. However, dye 2 does not generate catalytic amounts of hydrogen under standard conditions.

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