Hydrogen-atom transfer (HAT) initiated by intramolecular ligand-metal electron transfer
Hydrogen-atom transfer (HAT) is of key importance for several catalytic and biological processes, and provides an elegant access to C−H activation. In synthetic chemistry, a photoactivated metal complex is often employed to abstract an oxygen- or nitrogen-bound hydrogen, and the as-generated oxygen-...
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| Main Authors: | , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
2017
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| In: |
Chemistry - a European journal
Year: 2017, Volume: 23, Issue: 23, Pages: 5520-5528 |
| ISSN: | 1521-3765 |
| DOI: | 10.1002/chem.201605971 |
| Online Access: | Verlag, Volltext: http://dx.doi.org/10.1002/chem.201605971 Verlag, Volltext: https://onlinelibrary.wiley.com/doi/abs/10.1002/chem.201605971 
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| Author Notes: | Hendrik Herrmann, Elisabeth Kaifer, and Hans-Jörg Himmel |
| Summary: | Hydrogen-atom transfer (HAT) is of key importance for several catalytic and biological processes, and provides an elegant access to C−H activation. In synthetic chemistry, a photoactivated metal complex is often employed to abstract an oxygen- or nitrogen-bound hydrogen, and the as-generated oxygen- or nitrogen-centered radical is the hydrogen-atom acceptor for HAT. Here, we report the first examples for HAT processes initiated by one-electron oxidation of urea azines. A further novelty is that the HAT-initiating oxidation can be realized by intramolecular ligand-metal electron transfer in copper(II)-urea azine complexes. These complexes are first characterized in the solid state, in which they are stable. Electron-transfer-initiated HAT processes are observed upon dissolving the complexes in organic solvents, and the kinetics of these processes varies with the solvent polarity. The carbon-centered radicals formed by HAT can either be trapped with 2,2,6,6-tetramethylpiperidinyloxyl (TEMPO) or undergo radical recombination reactions with itself, yielding diamagnetic end-products. |
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| Item Description: | First published 20 February 2017 Gesehen am 08.06.2018 |
| Physical Description: | Online Resource |
| ISSN: | 1521-3765 |
| DOI: | 10.1002/chem.201605971 |