Free Cages and Encapsulation of Neutral Molecules

For the first time, the synthesis and characterization of a nanosized bis-cavitand hydrogen-bonded capsule 429, which is large euough to encapsulate two differeut guest molecules by Schane 3.87, are reported by J. Rebek, Jr. and cowotkers in [83] its size- and shape-selective binding has been used for exclusive encapsulation of the heteroguest pair benzene-para-xylene. 

Formation of the same social isomers by a-, P-, and y-picolines and toluene as co-guests by 

3 Encapsulation by Hydrogen-Bonded and Other Supramolecular Capsules 

The hydrogen-bonded eaging ligand 429 also encapsulates a series of W-protected amino acid 

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A cyclic trimer 409 (Scheme 5.1) has been obtained in [1] by condensation of Irialkoxy silane guest molecules encapsulated within the nanosized cavity of a self-assembled coordination capsule 488. If the free trimer 4W is a kinetic and short-lived product rapidly converting to the corresponding thermodynamically favored cyclic tetramer and other condensed products, its caged molecule is remarkably stable and remains intact over a long time at room temperature in both neutral aqueous solutions and acidic media (pH <1) [1]. 

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