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      Permanent link:
      https://www.ias.ac.in/article/fulltext/jcsc/104/02/0117-0131

    • Keywords

       

      Luminescence; TICT states; 4-(dialkylamino)pyrimidines; supersonic jet; electron transfer

    • Abstract

       

      The dual fluorescence (a andb) of 4-(dialkylamino)pyrimidines (4-DAAP) in solutions is explained in terms of the TICT state model. 4-DAAP form complexes with protic solvents: efficient radiationless depopulation is “switched on” by hydrogen bonding (HB). The photoinduced electron transfer is modified by HB or by coordination to the metal ion. In nitriles, two emitting states of 4-(N,N-dimethylamino)pyrimidine (I) and 4-(N,N-diethylamino)pyrimidine (II) reach equilibrium. In protic solvents, the fluorescencesa andb are not kinetically coupled: the different ground state complexes are responsible for each band. Jet-cooled 4-DAAP show only primary excited fluorescenceb. Microsolvation of pretwistedo-methylated compoundsIII andIV by small polar molecules, contrary to more planarI andII, gives rise to the long-wave (probably TICT) fluorescence.

    • Author Affiliations

       

      Jerzy Herbich1 2 Francisca Pérez Salgado1 Jerzy Karpiuk2

      1. Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44, Warsaw - 01-224, Poland
      2. Laboratory of Physical Chemistry, University of Amsterdam, Nieuwe Achtergracht 127, Amsterdam - 1018 WS, The Netherlands
    • Dates

       
  • Journal of Chemical Sciences | News

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