Supramolecular catalysis bonding

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. 

Supramolecular catalysis can involve passive effects such as the confining of two reactive molecules within a cavity and active effects where the catalyst interacts with the substrate via an active site. The active site may be metal-based as in other kinds of homogeneous catalyst based on transition metals or Lewis acids, or my involve interactions such as hydrogen bonding to bring about both polarisation of the reactants and their mutual spatial organisation. 

Aldehydes have been allylated with allyltributyltin, using supramolecular catalysis in acidic water at 60°C.196 Using j3-cyclodextrin as catalyst with all species at a 1 mmol level, high yields were obtained in a few hours. The catalyst, which can be recycled effectively, hydrogen bonds the aldehyde oxygen within the cavity. 

Margitfalvi et al. suggested that the catalytic systems Pt- and Pd-cinchona alkaloid-keto esters, are the first examples of a new class of heterogeneous catalytic reactions of supramolecular catalysis, where the prochiral group is part of a conjugated double bond system. 

The principles of supramolecular catalysis relate to enzyme catalysis, because weak chemical bonds involving well defined hydrogen bonds are essential. Lehnl formulated two main steps required for supramolecular reactivity and catalysis ... 

Ribaudo F, van Leeuwen PWNM, Reek JNH (2006) Supramolecular Dendritic Catalysis Noncovalent Catalyst Anchoring to Fimctionalized Dendrimers. 20 39-59 Richmond TG (1999) Metal Reagents for Activation and Functionalization of Carbon-Fluorine Bonds. 3 243-269... 

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