Carbon-carbon bond cleavage in radical anions of strained diphenylethane derivatives

Przemyslaw Maslak, Javier N. Narvaez, Thomas M. Vallombroso

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Fragmentation reactions of radical anions (mesolytic cleavages) of 1,1,2,2-tetraalkyl-1-(4′-nitrophenyl)-2-phenylethanes with varying degrees of steric strain have been studied in polar solvents. The rates and activation parameters obtained were compared to the corresponding values obtained for homolytic bond scissions in the neutrals. The free energies of activations for both types of reactions strongly depend on the strain present in the molecule. With the exception of the most crowded members of the series, nearly all of the strain is released in the transition state of homolytic reactions, and ca. 77% of it is relieved in the transition states of mesolysis. The mesolytic fragmentations have activation energies that are on average ca. 12.5 kcal/mol lower than the homolytic processes. The observed redox activation is shown to have thermodynamic origins.

Original languageEnglish (US)
Pages (from-to)X-12379
JournalJournal of the American Chemical Society
Volume117
Issue number50
StatePublished - Dec 20 1995

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Thermodynamics
Oxidation-Reduction
Anions
Negative ions
Carbon
Chemical activation
Derivatives
Free energy
Activation energy
Molecules
4-nitrophenyl

All Science Journal Classification (ASJC) codes

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

Cite this

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abstract = "Fragmentation reactions of radical anions (mesolytic cleavages) of 1,1,2,2-tetraalkyl-1-(4′-nitrophenyl)-2-phenylethanes with varying degrees of steric strain have been studied in polar solvents. The rates and activation parameters obtained were compared to the corresponding values obtained for homolytic bond scissions in the neutrals. The free energies of activations for both types of reactions strongly depend on the strain present in the molecule. With the exception of the most crowded members of the series, nearly all of the strain is released in the transition state of homolytic reactions, and ca. 77{\%} of it is relieved in the transition states of mesolysis. The mesolytic fragmentations have activation energies that are on average ca. 12.5 kcal/mol lower than the homolytic processes. The observed redox activation is shown to have thermodynamic origins.",
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Carbon-carbon bond cleavage in radical anions of strained diphenylethane derivatives. / Maslak, Przemyslaw; Narvaez, Javier N.; Vallombroso, Thomas M.

In: Journal of the American Chemical Society, Vol. 117, No. 50, 20.12.1995, p. X-12379.

Research output: Contribution to journalArticle

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