Selective Alcohol Oxidation by a Copper-TEMPO Catalyst: Mechanistic Insights by Simultaneously Coupled Operando EPR/UV-Vis/ATR-IR Spectroscopy
Dr. Jabor Rabeah1,*, Dr. Ursula Bentrup1,*, Prof. Dr. Reinhard Stößer2 and Prof. Dr. Angelika Brückner1,*
1.Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Str. 29a, 18059 Rostock (Germany)
2.Institut für Chemie-Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin-Adlershof (Germany)
Article first published online: 14 JUL 2015
DOI: 10.1002/anie.201504813
Abstract
The first coupled operando EPR/UV-Vis/ATR-IR spectroscopy setup
for mechanistic studies of gas-liquid phase reactions is presented and
exemplarily applied to the well-known copper/TEMPO-catalyzed
(TEMPO=(2,2,6,6-tetramethylpiperidin-1-yl)oxyl) oxidation of benzyl
alcohol. In contrast to previous proposals, no direct redox reaction
between TEMPO and CuI/CuII has been detected. Instead, the role of TEMPO is postulated to be the stabilization of a (bpy)(NMI)CuII-O2⋅−-TEMPO (bpy=2,2′-bipyridine, NMI=N-methylimidazole) intermediate formed by electron transfer from CuI to molecular O2.
All good things come in threes: Simultaneous operando
EPR/UV-vis/ATR-IR spectroscopy provides new mechanistic insights in
TEMPO-catalyzed aerobic alcohol oxidation.
TEMPO=(2,2,6,6-tetramethylpiperidin-1-yl)oxyl.
Visit Website
Visit Website
コメント