Photochemical Reactions of Arenecarbonitriles with Aliphatic Amines. 1. Effect of Arene Structure on Aminyl vs. α-Aminoalkyl Radical Formation

Frederick D Lewis*, Beth E. Zebrowski, Paul E. Correa

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

50 Scopus citations

Abstract

The photochemical reactions of several singlet arenecarbonitriles with aliphatic amines have been investigated. The reactions of 9-phenanthrenecarbonitrile with diethylamaine and its N-and α-C-deuterated derivatives result in exclusive N-H atom transfer to yield the diethylaminyl and 9-cyano-9,10-dihydrophenanthren-9-yl radicals in benzene solution. Increased solvent polarity results in the formation of both diethylaminyl and l-(ethylamino)ethyl radical. Similar results are obtained with 9-anthracenecarbonitrile. The competition between aminyl vs. α-aminoalkyl radical formation in this and other reactions is reviewed. Aminyl radical formation is characteristic of relatively nonpolar heteroexcimers in which hydrogen bonding may favor N-H transfer. Pure charge-transfer exciplexes, like alkoxyl radicals, yield predominantly the thermodynamically more stable α-aminoalkyl radical. The dominant reaction of the aminyl-phenanthren-9-yl radical pair in nonpolar solvent is combination to yield arene-amine adducts, which quantitatively lose HCN upon heating or chromatography. In contrast, the α-aminoalkyl-phenanthren-9-yl radical pairs formed in polar solvent disproportionate to yield reduced arene and oxidized amine, plausibly via radical pair electron transfer followed by proton transfer.

Original languageEnglish (US)
Pages (from-to)187-193
Number of pages7
JournalJournal of the American Chemical Society
Volume106
Issue number1
DOIs
StatePublished - Jan 1 1984

ASJC Scopus subject areas

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

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