Water soluble cryptophanes showing unprecedented affinity for xenon: Candidates as NMR-based biosensors

The structural and dynamical behaviors of the cryptophanes bearing molecules as well as their interaction with xenon are studied by using [.sup.1.H] and [.sup.128.Xe] NMR. The host molecules are shown to exist in aqueous solution under different conformations in very slow exchange whereas the cryptophanes in such conformation are unable to complex xenon.