The effect of remote substituents in free radical addition reactions: New evidence for the penultimate unit effect

Michelle L. Coote, Thomas P. Davis, Leo Radom

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31 Citations (Scopus)


Ab initio molecular orbital calculations of the barrier for the addition of gamma-substituted propyl radicals to various alkenes indicate that substituents at the gamma position of a radical can significantly affect the barrier. This finding supports recent experimental evidence for an enthalpic penultimate unit effect in free-radical copolymerization. For the reactions studied in the present work, this penultimate unit effect is consistent with a significant polar contribution.

Original languageEnglish
Pages (from-to)91-96
Number of pages6
JournalJournal of Molecular Structure: THEOCHEM
Publication statusPublished - 2 Apr 1999
Externally publishedYes


  • Addition
  • Free radical
  • Gamma substituent effect
  • Penultimate unit effect
  • Polymerization

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