trans-Stilbene-Amine Exciplexes. Behavior of the Exciplex, Solvent-Separated Radical Ion Pair, and Free Radical Ions

Walter Hub, Siegfried Schneider, Friedrich Doerr, Joe D. Oxman, Frederick D. Lewis

Research output: Contribution to journalArticlepeer-review

54 Scopus citations


The interaction of singlet trans-stilbene with several trialkylamines and diamines in acetonitrile solution has been investigated by a combination of steady-state measurements and time-resolved resonance Raman spectroscopy. Adduct formation between trans-stilbene and acyclic monoamines is proposed to occur via a short-lived exciplex (contact radical ion pair) intermediate, which is not quenched by ground-state amine. A solvent-separated radical ion pair is formed either directly from an encounter complex or via the exciplex and decays by intersystem crossing to yield triplet trans-stilbene, dissociation to yield free radical ions, or quenching by ground-state amine. Intersystem crossing is more rapid for the diamines vs. monoamines, resulting in a lower yield of free radical ions. Quenching of the solvent-separated radical ion pair by ground-state amine is subject to the same stereoelectronic effect as observed for exciplex quenching in nonpolar solvent. Free trans-stilbene anion radical decay is by recombination with amine cation radical and is independent of amine structure or concentration.

Original languageEnglish (US)
Pages (from-to)708-715
Number of pages8
JournalJournal of the American Chemical Society
Issue number3
StatePublished - Feb 1 1984

ASJC Scopus subject areas

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


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