Water-soluble, dynamic hemicarcerands capsules that self-assemble in water from two cavitands and four diamines upon addition of a suitable, templating, guest molecule can be used as molecular reaction flasks (pictured). As a consequence of guest confinement, reactions carried out inside molecular capsules often proceed in a different manner compared to the bulk.

Ralf Warmuth and co-workers, Department of Chemistry and Chemical Biology, Rutgers, New Brunswick, USA, have developed a rational design concept for the multicomponent assembly of polycavitand nanocapsules by using dynamic covalent chemistry.
Photolysis of an “imprisoned” diazirine inside a hemicarcerand capsule yielded the Bredt olefin. It survives for days at room temperature protected from dimerization or reaction with solvent by the surrounding capsule.

• Assembly of Water-Soluble, Dynamic, Covalent, Container Molecules and Their Application in the Room-Temperature Stabilization of Protoadamantene,
  Z. Lin, J. Sun, B. Efremovska, R. Warmuth,
  Chem. Eur. J. 2012, 18.
  DOI:10.1002/chem.201200602