Development of a Sub-group of the Cucurbituril Family, Hemicucurbiturils: Synthesis and Supramolecular Chemistry

As a sub-group of the cucurbituril family, hemicucurbiturils have become increasingly prominent as a new platform in host-guest chemistry. Their flexible structures, due to only one methylene chain bridging the urea moieties, endow them with different properties to those of cucurbiturils, such as solubility in common organic solvents, accommodation of anions in their cavities, and so on. In this review, we survey the synthesis of hemicucurbiturils and their derivatives involving cyclohexylhemicucurbiturils, bambusurils, and biotinurils, as well as their supramolecular properties of host-guest interactions, molecular recognitions, and supramolecular catalysis. The review aimed to achieve a comprehensive understanding of the new class of macrocylic compounds for both investigators already engaged in this research field and those interested in gaining insight into these macrocycles.