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C−H Bond Activation by an Imido Cobalt(III) and the Resulting Amido Cobalt(II) Complex
Author(s) -
Reckziegel Alexander,
Pietzonka Clemens,
Kraus Florian,
Werncke C. Gunnar
Publication year - 2020
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201914718
Subject(s) - cobalt , chemistry , nitrene , bond dissociation energy , catalysis , amide , photochemistry , amination , bond cleavage , dissociation (chemistry) , medicinal chemistry , crystallography , polymer chemistry , stereochemistry , inorganic chemistry , organic chemistry
The 3d‐metal mediated nitrene transfer is under intense scrutiny due to its potential as an atom economic and ecologically benign way for the directed amination of (un)functionalised C−H bonds. Here we present the isolation and characterisation of a rare, trigonal imido cobalt(III) complex, which bears a rather long cobalt–imido bond. It can cleanly cleave strong C−H bonds with a bond dissociation energy of up to 92 kcal mol −1 in an intermolecular fashion, unprecedented for imido cobalt complexes. This resulted in the amido cobalt(II) complex [Co(hmds) 2 (NH t Bu)] − . Kinetic studies on this reaction revealed an H atom transfer mechanism. Remarkably, the cobalt(II) amide itself is capable of mediating H atom abstraction or stepwise proton/electron transfer depending on the substrate. A cobalt‐mediated catalytic application for substrate dehydrogenation using an organo azide is presented.