Photocatalytic Oxidation of α-C-H Bonds in Unsaturated Hydrocarbons through a Radical Pathway Induced by a Molecular Cocatalyst.

Autor: Zhao G; Laboratory of Industrial Chemistry, Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780, Bochum, Germany., Hu B; Laboratory of Industrial Chemistry, Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780, Bochum, Germany.; Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470, Mülheim an der Ruhr, Germany., Busser GW; Laboratory of Industrial Chemistry, Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780, Bochum, Germany., Peng B; Laboratory of Industrial Chemistry, Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780, Bochum, Germany.; Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470, Mülheim an der Ruhr, Germany., Muhler M; Laboratory of Industrial Chemistry, Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780, Bochum, Germany.; Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470, Mülheim an der Ruhr, Germany.
Jazyk: angličtina
Zdroj: ChemSusChem [ChemSusChem] 2019 Jun 21; Vol. 12 (12), pp. 2795-2801. Date of Electronic Publication: 2019 Jun 06.
DOI: 10.1002/cssc.201900394
Abstrakt: To improve the photocatalytic oxidation of α-C-H bonds in unsaturated hydrocarbons, N-hydroxyphthalimide (NHPI) was used as a molecular cocatalyst with CdS as the photoabsorber. Compared with previously reported photocatalysts involving solid cocatalysts, metal-free NHPI offers better sustainability in addition to the significantly enhanced performance as cocatalyst. The photogenerated holes were transferred into the more active phthalimide-N-oxyl radical (PINO) by reacting with NHPI. In this way, α-C-H bond oxidation was significantly improved through the activation by PINO; even for the sluggish toluene oxidation, the apparent quantum efficiency was as high as 36.5 %. The effects of substrates/NHPI concentration ratio, reaction temperature, and time as well as the reaction intermediates were comprehensively studied. It was possible to identify ketones/aldehydes as the primary products, and overoxidation was controlled by adjusting the substrates/NHPI concentration ratio and reaction time. Thus, the radical path induced by the NHPI-PINO redox pair is an efficient alternative to boost the sluggish photocatalytic oxidation of α-C-H bonds.
(© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)
Databáze: MEDLINE
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