The N‐Bromo‐Hammick Intermediate
We report the characterization of bromopyridin-2-ylidene, the N-bromo-Hammick intermediate, isolated in solid neon at 4.4 K. Computations (B2PLYP, NEVPT2), IR, and UV/vis spectroscopy characterize this intermediate as a singlet carbene with a vacant σ*-type frontier orbital. This unusual electronic structure (σ<sup>2</sup>σ*<sup>0</sup>) allows the carbene to isomerize to its more stable pyridine tautomer via a planar transition state, avoiding the deviation from planarity seen in other singlet carbenes. The compound's reaction with molecular hydrogen faces a minor but prohibitive barrier (8.4 kcal mol<sup>-1</sup>) at the low temperatures of the experiment.
Authors
- J. Philipp Wagner (ORCID: https://orcid.org/0000-0002-1433-0292)
- Virinder Bhagat (ORCID: https://orcid.org/0000-0003-4146-308X)
Institutions
- University of Bremen (DE)
- University of Tübingen (DE)
Publication Details
- Journal
- Chemistry - A European Journal
- Published
- 2025-09-26
- DOI
- https://doi.org/10.1002/chem.202502434
- Primary Topic
- N-Heterocyclic Carbenes in Organic and Inorganic Chemistry
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- Deutsche Forschungsgemeinschaft
- Eberhard Karls Universität Tübingen
- Boehringer Ingelheim Stiftung