Based on their high magnetic properties, TurboBeads represent a promising substrate for semi-heterogeneous catalysts. In this paper, Wittmann et al. functionalized TurboBeads nanoparticles with a pyrene-tagged palladium NHC complex. This chemical group was shown to immobilize reversibly on the surface of the TurboBeads and the catch/release could be controlled by adjusting the reaction temperature. This catalyst catch-release concept was investigated in detail for the hydroxycarbonylation of aryl halides in water. 14 catalytical cycles utilizing the same material were shown and no effect on the velocity of the reactions could be observed.
Angew. Chem. Int. Ed. 2010 (link)
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