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From Si(II) to Si(IV) and Back: Reversible Intramolecular Carbon-Carbon Bond Activation by an Acyclic Iminosilylene.

Daniel WendelAmelie PorzeltFabian A D HerzDebotra SarkarChristian JandlShigeyoshi InoueBernhard Rieger
Published in: Journal of the American Chemical Society (2017)
Reversibility is fundamental for transition metal catalysis, but equally for main group chemistry and especially low-valent silicon compounds, the interplay between oxidative addition and reductive elimination is key for a potential catalytic cycle. Herein, we report a highly reactive acyclic iminosilylsilylene 1, which readily performs an intramolecular insertion into a C═C bond of its aromatic ligand framework to give silacycloheptatriene (silepin) 2. UV-vis studies of this Si(IV) compound indicated a facile transformation back to Si(II) at elevated temperatures, further supported by density functional theory calculations and experimentally demonstrated by isolation of a silylene-borane adduct 3 following addition of B(C6F5)3. This tendency to undergo reductive elimination was exploited in the investigation of silepin 2 as a synthetic equivalent of silylene in the activation of small molecules. In fact, the first monomeric, four-coordinate silicon carbonate complex 4 was isolated and fully characterized in the reaction with carbon dioxide under mild conditions. Additionally, the exposure of 2 to ethylene or molecular hydrogen gave silirane 5 and Si(IV) dihydride 6, respectively.
Keyphrases
  • density functional theory
  • transition metal
  • room temperature
  • carbon dioxide
  • molecular dynamics
  • quantum dots
  • molecular dynamics simulations
  • highly efficient
  • electron transfer