Proton transfer reactions of photogenerated cyanoaromatic-methylaromatic radical ion pairs†

Frederick D. Lewis*, James R. Petisce

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

46 Scopus citations

Abstract

The photochemical reactions of a number of cyanoaromatic (acceptor) and methylaromatic (donor) molecules have been investigated. These reactions can result in the formation of photosubstitution products or benzyl radical coupling products. A survey of our results and previously published data indicates that exergonic photostimulated electron transfer is a necessary but not sufficient condition for the observation of reaction products. The efficiency of proton transfer from the donor cation radical to the acceptor anion radical is determined by the kinetic acidity and basicity of the radical ion pair. Mechanistic evidence is presented which indicates that proton transfer requires diffusion apart and reencounter of the initially formed radical ion pair. Predominant radical pair combination is observed for anion radicals which yield electron-deficient free radicals upon protonation, whereas predominant cage escape and benzyl radical coupling is observed for anion radicals which yield electron-rich free radicals upon protonation.

Original languageEnglish (US)
Pages (from-to)6207-6217
Number of pages11
JournalTetrahedron
Volume42
Issue number22
DOIs
StatePublished - 1986

ASJC Scopus subject areas

  • Biochemistry
  • Drug Discovery
  • Organic Chemistry

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