Large Carbocyclic Cavities for the Selective Inclusion of Organic Guest Molecules in Aqueous Solution

The first host molecule without heteroatom in its skeleton, 1, is soluble in water as the anion; compared to heterocycles, it has the advantage of being chemically more stable and, via transformations of the side chains, more variable. Compounds of type 1 are complexing agents for quaternary ammonium salts and, if the carboxy groups can turn inward, for metal cations.