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Photo-Initiated Cobalt-Catalyzed Radical Olefin Hydrogenation |
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| Authors: | Sier Sang Tobias Unruh Dr Serhiy Demeshko Dr Luis I Domenianni Nicolaas P van Leest Dr Philipp Marquetand Dr Felix Schneck Dr Christian Würtele Felix J de Zwart Prof?Dr Bas de Bruin Prof?Dr?Dr?hc Leticia González Prof?Dr Peter Vöhringer Prof?Dr Sven Schneider |
| Institution: | 1. Universität Göttingen, Institut für Anorganische Chemie, Tammannstraße 4, 37077 Göttingen, Germany;2. Institut für Physikalische und Theoretische Chemie, Rheinische Friedrich-Wilhelms-Universität, Wegelerstrasse 12, 53117 Bonn, Germany;3. Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands;4. Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Straße 17, 1090 Vienna, Austria |
| Abstract: | Outer-sphere radical hydrogenation of olefins proceeds via stepwise hydrogen atom transfer (HAT) from transition metal hydride species to the substrate. Typical catalysts exhibit M?H bonds that are either too weak to efficiently activate H2 or too strong to reduce unactivated olefins. This contribution evaluates an alternative approach, that starts from a square-planar cobalt(II) hydride complex. Photoactivation results in Co?H bond homolysis. The three-coordinate cobalt(I) photoproduct binds H2 to give a dihydrogen complex, which is a strong hydrogen atom donor, enabling the stepwise hydrogenation of both styrenes and unactivated aliphatic olefins with H2 via HAT. |
| Keywords: | cobalt hydrogenation hydrogen atom transfer photochemistry transient absorption spectroscopy |