Transition-Metal Encapsulation within Supramolecular Diphosphine Capsules

This review provides a detailed overview on the research carried out in self-assembled supramolecular capsules enabling encapsulation of transition metals within their inner space. The supramolecular assemblies discussed are based on cationic/anionic interactions between cone-shaped building blocks, derived from quaternary ammonium and sulfonated salts, which upon assembly give rise to closed cavitands. Furthermore, one or both of the ionic building blocks contain diphosphine groups located at the cavity core. Thus, upon chelation of a transition-metal ion to the phosphorus(III) donor atoms, the metal fragment lies positioned in the molecular container. In addition, metal coordination does not affect the overall structure of the supramolecular capsule.