Supramolecular Anchoring of Catalysts to Support

The question remains how large and diverse a ligand library should be to provide a catalyst for every substrate. We hope to answer this question in due course. 

The first examples of noncovalent anchoring of catalysts to soluble supports appeared in the literature in 2001. Concurrently, Mecking and ourselves were 

A rhodium catalyst based on the glycine-urea functionalized Xantphos ligand was subsequently used in combination vdth the same support material, as a catalyst for the hydroformylation of 1-octene. In eleven consecutive reactions the catalyst did not 

These noncovalently anchored catalysts in general exhibit a behavior similar to their covalently bound analogues, but can now be separated from the support after the reactions by a simple filtration step. So far, these immobilized systems have not been used in continuous flow reactors. 

Supramolecular chemistry also provides new tools for catalyst anchoring. We have shown that catalysts can be noncovalently attached to various soluble and insoluble supports, affording recyclable catalysts. Interestingly, the reversible nature of the noncovalent bond gives rise to new opportunities. In the first instance, we foresee an important role for supramolecular bidentate ligands in combinatorial catalysis - but as a consequence of the entirely new properties many new applications are envisioned. We look forward to new developments and results in this exciting emerging area of supramolecular catalysis. 

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