Confinement of Water-Soluble Cationic Substrates in a Cationic Molecular Cage by Capping the Portals with Tripodal Anions.

The ability of a cationic coordination cage to encapsulate molecular guests is enhanced by non-covalent capping of the cage portals with tripodal anions. The capped cage provides new cation binding sites at the portals, which enable accommodation of cationic substrates within the cationic cage. In addition, non-covalent capping allows neutral guests in the cage to be exchanged for cationic ones on demand.