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Gauging Radical Stabilization with Carbenes.

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.

SUBMITTER: Breitwieser K

PROVIDER: S-EPMC9545232 | biostudies-literature | 2022 Sep

REPOSITORIES: biostudies-literature

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Gauging Radical Stabilization with Carbenes.

Breitwieser Kevin K Bahmann Hilke H Weiss Robert R Munz Dominik D

Angewandte Chemie (International ed. in English) 20220804 37

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 ...[more]

PMID: 35796423

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