Generation, entrapment, and spectroscopic characterization of radical cations of α,ω-diphenyl polyenes within the channels of pentasil zeolites

Vaidhyanathan Ramamurthy, Jonathan V. Caspar, David R. Corbin

Research output: Contribution to journalArticle

112 Citations (Scopus)

Abstract

Inclusion of all-trans-α,ω-diphenyl polyenes (trans-stilbene, 1,4-diphenyl-1,3-butadiene, 1,6-diphenyl-1,3,5-hexatriene, 1,8-diphenyl-1,3,5,7-octatetraene) in thermally activated Na-ZSM-5 zeolite leads to the rapid formation of cation radicals of the polyenes. These cation radicals are stabilized within the zeolite host and are conveniently studied by conventional spectroscopic techniques (ESR, UV-vis-NIR diffuse reflectance, emission) enabling us to determine for the first time the steady state fluorescence spectrum of the 1,6-diphenyl-1,3,5-hexatriene and 1,8-diphenyl-1,3,5,7-octatetraene cation radicals. Our method of generation and stabilization of organic cation radicals appears to be both general in scope and simple in practice. While the mechanism of oxidation remains unclear, it appears that the presence of aluminum in the zeolite is a requirement; as the Si/Al ratio decreases the extent of oxidation increases. Using a series of substituted stilbenes of known redox potential leads to an estimated redox potential of 1.65 ± 0.1 eV vs SCE for the zeolite-based oxidant.

Original languageEnglish
Pages (from-to)594-600
Number of pages7
JournalJournal of the American Chemical Society
Volume113
Issue number2
StatePublished - Jan 16 1991
Externally publishedYes

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Polyenes
Zeolites
Cations
Positive ions
Diphenylhexatriene
Stilbenes
Oxidation-Reduction
Oxidation
Aluminum
Butadiene
Oxidants
Paramagnetic resonance
Stabilization
Fluorescence
diphenyl
1,3,5,7-octatetraene

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

Generation, entrapment, and spectroscopic characterization of radical cations of α,ω-diphenyl polyenes within the channels of pentasil zeolites. / Ramamurthy, Vaidhyanathan; Caspar, Jonathan V.; Corbin, David R.

In: Journal of the American Chemical Society, Vol. 113, No. 2, 16.01.1991, p. 594-600.

Research output: Contribution to journalArticle

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