Delocalization of free electron density through phenylene-ethynylene: Structural changes studied by time-resolved infrared spectroscopy

Dmitry E. Polyansky, Evgeny O. Danilov, Sergey V. Voskresensky, Michael A.J. Rodgers, Douglas C. Neckers

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We have studied the photochemistry of 1,4-bis(2-[4-tert-butylperoxycarbonylphenyl]ethynyl)benzene (1) and tert-butyl 4-(2-{4-[2-(4-phenyloxycarbonylphenyl)-1-ethynyl]phenyl}-1-ethynyl)peroxybenzoate (2). Excitation of 1 and 2 by a 355-nm laser pulse leads to the rapid formation of aroyloxyl radicals. An unpaired electron conjugated with the phenylene-ethynylene core is substantially delocalized over the π-system of the chromophore. The -CC- vibrational frequencies of these radicals are red-shifted relative to 1 and 2 as measured by time-resolved IR spectroscopy. This shift is attributed to the change in the triple bond character due to delocalization of the free electron.

Original languageEnglish
Pages (from-to)13452-13453
Number of pages2
JournalJournal of the American Chemical Society
Issue number39
Publication statusPublished - Oct 5 2005


ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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