Activation of molecular oxygen by a cobalt(II) tetra‐NHC complex

Jonas F. Schlagintweit, Philipp J. Altmann, Alexander D. Böth, Benjamin J. Hofmann, Christian Jandl, Clemens Kaußler, Linda Nguyen, Robert M. Reich, Alexander Pöthig, Fritz E. Kühn

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Abstract

The first dicobalt(III) μ2-peroxo N-heterocyclic carbene (NHC) complex is reported. It can be quantitatively generated from a cobalt(II) compound bearing a 16-membered macrocyclic tetra-NHC ligand via facile activation of dioxygen from air at ambient conditions. The reaction proceeds via an end-on superoxo intermediate as demonstrated by EPR studies and DFT. The peroxo moiety can be cleaved upon addition of acetic acid, yielding the corresponding CoIII acetate complex going along with H2O2 formation. In contrast, both CoII and CoIII complexes are also studied as catalysts to utilize air for olefin and alkane oxidation reactions; however, not resulting in product formation. The observations are rationalized by DFT-calculations, suggesting a nucleophilic nature of the dicobalt(III) μ2-peroxo complex. All isolated compounds are characterized by NMR, ESI-MS, elemental analysis, EPR and SC-XRD.
Original languageEnglish
Pages (from-to)1311-1315
Number of pages5
JournalChemistry – A European Journal
Volume27
Issue number4
Early online date30 Oct 2020
DOIs
Publication statusPublished - 18 Jan 2021

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