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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.

The (super 1)H chemical shift variations are monitored under xenon pressures to determine the noble gas binding constant. The comparison to the exchange experienced by protein protons shows that the exchange between the open and closed conformations of wild-type bacteriophage T4 lysozome is not required for xenon binding.

The combination of different xenon-based NMR methods is used to investigate the hydrophobic cavity of lipid transfer protein from Nicotiana tabacum. The study of (super 129)Xe chemical shifts and relaxation times as a function of the noble gas or protein concentrations provides insight into the affinity of xenon to the protein.

The structural characterization of stable complexes of pentavalent uranyl synthesized from the reaction of the complex with the bulky amine-phenolate ligand potassium salt [K.sub.2](salan-[super]t[Bu.sub.2]) or the Schiff base ligand potassium salt [K.sub.2](salophen-[super]t[Bu.sun.2]) in pyridine is described. The presence of a back-bonding interaction in the pentavalent uranyl complexes possibly contributed significantly to the observed solution stability of the [U[O.sub.2](salan-[super]t[Bu.sub.2])(py)K] and [U[O.sub.2](salophen-[super]t[Bu.sub.2])(py)K] complexes with respect to disproportionation and hydrolysis.