Different behavior of nitrenes and carbenes on photolysis and thermolysis: Formation of azirine, ylidic cumulene, and cyclic ketenimine and the rearrangement of 6-phenanthridylcarbene to 9-phenanthrylnitrene

David Kvaskoff, Pawel Bednarek, Lisa George, Sreekumar Pankajakshan, Curt Wentrup

Research output: Contribution to journalArticle

Abstract

Flash vacuum thermolysis (FVT) of 9-azidophenanthrene 8, 6-(5-tetrazolyl)phenanthridine 18, and [1,2,3]triazolo[l,5-f]phenanthridine 19 yields 9-cyanofluorene 12 as the principal product and 4-cyanofluorene as a minor product. In all cases, when the product is condensed at or below 77 K, the seven-membered ring ketenimine 24 is detectable by IR spectroscopy (1932 cm-1) up to 200 K. Photolysis of Ar matrix isolated 8 at λ = 308 or 313 nm generates at first the azirine 26, rapidly followed by the ylidic cumulene 27. The latter reverts to azirine 26 at λ > 405 nm, and the azirine reverts to the ylidic cumulene at 313 nm. Nitrene 9 is observed by ESR spectroscopy following FVT of either azide 8, tetrazole 18, or triazole 19 with Ar matrix isolation of the products. Nitrene 9 and carbene 21 are observed by ESR spectroscopy in the Ar matrix photolyses of azide 8 and triazole 19, respectively.

Original languageEnglish (US)
Pages (from-to)7947-7955
Number of pages9
JournalJournal of Organic Chemistry
Volume70
Issue number20
DOIs
StatePublished - Sep 20 2005

ASJC Scopus subject areas

  • Organic Chemistry

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