Umpolung in a Pair of Cobalt(III) Terminal Imido/Imidyl Complexes

Mao W, Fehn D, Heinemann FW, Scheurer A, Van Gastel M, Jannuzzi SA, Debeer S, Munz D, Meyer K (2022)

Publication Type: Journal article

Publication year: 2022

Journal

DOI: 10.1002/anie.202206848

Abstract

Reaction of the Co^I complex [(TIMMN^mes)Co^I](PF6) (1) (TIMMN^mes=tris-[2-(3-mesityl-imidazolin-2-ylidene)-methyl]amine) with mesityl azide yields the Co^III imide [(TIMMN^mes)Co^III(NMes)](PF6) (2). Oxidation of 2 with [FeCp2](PF6) provides access to a rare Co^III imidyl [(TIMMN^mes)Co(NMes)](PF6)2 (3). Single-crystal X-ray diffractometry and EPR spectroscopy confirm the molecular structure of 3 and its S= (Formula presented.) ground state. ENDOR, X-ray absorption spectroscopy and computational analyses indicate a ligand-based oxidation; thus, an imidyl-radical electronic structure for 3. Migratory insertion of one ancillary NHC to the imido ligand in 2 gives the Co^I N-heterocyclic imine (4) within 12 h. Conversely, it takes merely 0.5 h for 3 to transform to the Co^II congener (5). The migratory insertion in 2 occurs via a nucleophilic attack of the imido ligand at the NHC to give 4, whereas in 3, a nucleophilic attack of the NHC at the electrophilic imidyl ligand yields 5. The reactivity shunt upon oxidation of 2 to 3 confirms an umpolung of the imido ligand.

Authors with CRIS profile

Involved external institutions

Max-Planck-Institut für Kohlenforschung (MPI KoFo) / Max Planck Institute for Coal Research Germany (DE) Max-Planck-Institut für Chemische Energiekonversion (MPI CEC) / Max-Planck-Institute for Chemical Energy Conversion Germany (DE)

How to cite

APA:

Mao, W., Fehn, D., Heinemann, F.W., Scheurer, A., Van Gastel, M., Jannuzzi, S.A.,... Meyer, K. (2022). Umpolung in a Pair of Cobalt(III) Terminal Imido/Imidyl Complexes. Angewandte Chemie International Edition. https://doi.org/10.1002/anie.202206848

MLA:

Mao, Weiqing, et al. "Umpolung in a Pair of Cobalt(III) Terminal Imido/Imidyl Complexes." Angewandte Chemie International Edition (2022).

BibTeX: Download