Supramolecular barrels from amphiphilic rigid-flexible macrocycles.

Precise control of supramolecular objects requires the rational design of molecular components, because the information determining their specific assembly should be encoded in their molecular architecture. In this context, diverse self-assembling molecules including liquid crystals, dendrimers, block copolymers, hydrogen-bonded complexes and rigid macrocycles are being created as a means of manipulating supramolecular structure. Incorporation of a stiff rod-like building block into an amphiphilic molecular architecture leads to another class of self-assembling molecules. Aggregation of rod building blocks can generate various nanoscale objects including bundles, ribbons, tubules and vesicles, depending on the molecular structure and/or the presence of a selective solvent. We present here an unusual example of supramolecular barrels in the solid and in aqueous solution, based on the self-assembly of amphiphilic rigid-flexible macrocycles driven by non-covalent interactions. Preliminary experiments show that these amphiphilic macrocycles are membrane-active. The amphiphilic macrocycles might thus lead to an excellent model system for exploring biological processes in supramolecular materials.