The letter describes a novel approach for immobilization of 2,2,6,6-tetramethylpiperidine-1-oxyl
(TEMPO) derivatives by cation-exchange reaction of TEMPO ammonium
salts in a commercially available saponite. The organic-inorganic
hybrid material is readily prepared and characterized by solid-state ¹H
NMR spectroscopy. The hybrid material can be used as recyclable
catalyst for oxidation of various alcohols. High catalytic activity
for up to 10 runs is obtained. Leaching of the nitroxide salt out
of the saponite occurs to a small extent. However, original high
activity of the hybrid material can be restored by simply reloading
the hybrid material with nitroxide salt by cation exchange.
alcohol oxidation - 2,2,6,6-tetramethylpiperidine-1-oxyl - TEMPO - catalyst immobilization
- catalysis - solid-state NMR spectroscopy