Stabilization of a Reactive Cationic Species by Supramolecular Encapsulation

When encapsulated as a guest in the cavity of the tetrahedral cluster Na12[Ga4L6], the phosphonium cation [Me2C(OH)PEt3]+ (1), normally unstable in aqueous solution (see equilibrium (1)), can be observed in water. The host–guest complex Na12[Ga4L6⊂1] has been observed by 1H and 31P{1H} NMR spectroscopy as well as by mass spectrometry. This is a rare example of a self-assembled supramolecular cluster stabilizing a reactive species by encapsulation. L=multidentate ligand.