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Updated: Jul 1, 2025

Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization
Published on: November 29, 2018
Ambiphilicity of ring-expanded N-heterocyclic carbenes
François Vermersch1, Victor T Wang1, Mehdi Abdellaoui1
1UCSD-CNRS Joint Research Chemistry Laboratory (IRL 3555), Department of Chemistry and Biochemistry, University of California La Jolla San Diego California 92093-0358 USA rjazzar@ucsd.edu gbertrand@ucsd.edu.
Abstract:
N-heterocyclic carbenes, such as imidazole-2-ylidenes and imidazolin-2-ylidenes, the popular class of singlet carbenes introduced by Arduengo in 1991 have not been shown to be ambiphilic owing to the two σ-withdrawing, π-donating amino groups flanking the carbene centre. However, our experimental data suggest that ring-expanded N-heterocyclic carbenes (RE-NHCs), especially the seven and eight membered rings, are significantly ambiphilic. Our results also show that the steric environment in RE-NHCs can become a determining factor for controlling the E-H bond activation.
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