Reversible Homolysis of a Carbon-Carbon σ-Bond Enabled by Complexation-Induced Bond-Weakening

Suhong Kim, Pan Pan Chen, K. N. Houk, Robert R. Knowles

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


A case study of catalytic carbon-carbon σ-bond homolysis is presented. The coordination of a redox-active Lewis acid catalyst reduces the bond-dissociation free energies of adjacent carbon-carbon σ-bonds, and this complexation-induced bond-weakening is used to effect reversible carbon-carbon bond homolysis. Stereochemical isomerization of 1,2-disubstituted cyclopropanes was investigated as a model reaction with a ruthenium (III/II) redox couple adopted for bond weakening. Results from our mechanistic investigation into the stereospecificity of the isomerization reaction are consistent with selective complexation-induced carbon-carbon bond homolysis. The ΔG‡ of catalyzed and uncatalyzed reactions were estimated to be 14.4 and 40.0 kcal/mol, respectively with the computational method, (U)PBE0-D3/def2-TZVPP-SMD(toluene)//(U)B3LYP-D3/def2-SVP. We report this work as the first catalytic example where the complexation-induced bond-weakening effect is quantified through transition state analysis.

Original languageEnglish (US)
Pages (from-to)15488-15496
Number of pages9
JournalJournal of the American Chemical Society
Issue number34
StatePublished - Aug 31 2022

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • Biochemistry
  • Catalysis
  • Colloid and Surface Chemistry


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