The complex photo-rearrangement of a heterocyclic N-oxide: Kinetics from picoseconds to minutes

Cordes, T., Regner, N., Heinz, B., Borysova, E., Ryseck, G. & Gilch, P., 2009, In : Journal of Photochemistry and Photobiology A: Chemistry. 206, 1, p. 10-17 8 p.

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  • Thorben Cordes
  • Nadja Regner
  • Björn Heinz
  • Elina Borysova
  • Gerald Ryseck
  • Peter Gilch
The photo-induced rearrangement of 2-benzoyl-3-phenylquinoxaline-1,4-dioxide yielding 1,3-dibenzoylbenzimidazolone (DBBI) is studied by time-resolved fluorescence, UV/vis absorption, and IR spectroscopy. This complex rearrangement occurs on time scales ranging from 0.1 ps up to minutes. Processes within the excited singlet state(s) (0.1–1 ps) are followed by a multi-phasic depletion of the fluorescent states (time constants of 1–200 ps). During that depletion both a triplet state and a precursor of the photo-product are populated. In absence of oxygen the triplet state decays in 8 µs. It does not participate in the formation of the photoproduct. A process with a time constant of 77 min terminates the product formation. It can be assigned to a hindered rotation of the benzoyl residues in DBBI.
Original languageEnglish
Pages (from-to)10-17
Number of pages8
JournalJournal of Photochemistry and Photobiology A: Chemistry
Issue number1
Publication statusPublished - 2009


  • IR spectroscopy, UV/vis spectroscopy, Fluorescence spectroscopy, Femtosecond spectroscopy, Heteroaromatic N-oxides

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