Self‐Assembly of Organic Supramolecular Capsules

Abstract

The present contribution is aimed at illustrating to the reader the state of the art on the construction of artificial, finite supramolecular assemblies characterized in solution by capsular shape held together by means of weak intermolecular noncovalent forces in solution, except metal‐ligand coordination. These supramolecular assemblies provide cavities of correct size and shape where molecules of guests present in solution can be hosted if the available space is appropriately filled. Guests within the cavity are held for lifetimes ranging from milliseconds to hours, depending on the number and quality of weak intermolecular forces and the number of subunits that compose the capsule. The in–out process of exchange of guests influences their behavior profoundly, enabling a series of applications spanning from molecular recognition of one up to several guests at a time with creation of new forms of isomerism derived by guest–guest interactions to supramolecular catalysis, which is the ultimate goal of such kind of assemblies. A further intriguing aspect of self‐assembled capsules is chirality that can be implemented in the subunits, that forms the capsule, or that can be the result of a particular arrangement of achiral units. In the latter case, the presence of strong attractive forces between the subunits enables to template the formation of enantiomerically enriched capsules with enantiopure guests based on achiral units via the chiral memory effect.