Gauging Radical Stabilization with Carbenes

Language
en
Document Type
Article
Issue Date
2022-11-23
First published
2022-09-05
Issue Year
2022
Authors
Breitwieser, Kevin
Bahmann, Hilke
Weiss, Robert
Munz, Dominik
Editor
Publisher
John Wiley & Sons, Inc.
Abstract

Abstract Carbenes, including N‐heterocyclic carbene (NHC) ligands, are used extensively to stabilize open‐shell transition metal complexes and organic radicals. Yet, it remains unknown, which carbene stabilizes a radical well and, thus, how to design radical‐stabilizing C‐donor ligands. With the large variety of C‐donor ligands experimentally investigated and their electronic properties established, we report herein their radical‐stabilizing effect. We show that radical stabilization can be understood by a captodative frontier orbital description involving π‐donation to‐ and π‐donation from the carbenes. This picture sheds a new perspective on NHC chemistry, where π‐donor effects usually are assumed to be negligible. Further, it allows for the intuitive prediction of the thermodynamic stability of covalent radicals of main group‐ and transition metal carbene complexes, and the quantification of redox non‐innocence.

Journal Title
Angewandte Chemie International Edition
Volume
61
Issue
37
Citation
Angewandte Chemie International Edition 61.37 (2022): e202206390. <https://onlinelibrary.wiley.com/doi/full/10.1002/anie.202206390>
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