Chapter 7. Cucurbituril Containing Supramolecular Nanomaterials

Smart functional nanostructures that are adaptive and responsive to different external stimuli (light, heat, pH, competitive guests, redox etc.) could be assembled in aqueous milieus by making use of supramolecular chemistry, which basically relies on reversible noncovalent interactions, including hydrogen bonding, p–p stacking, van der Waals forces or hydrophobic interactions. Host–guest inclusion complex formation is particularly appealing as high selectivity between the host and guest molecules provides dynamic but strong interactions and offers a number of possibilities in the design of supramolecular nanostructures with desirable topological diversity and programmable functions for specific applications. The macrocycles most commonly used as host molecules are cyclodextrins, pillarenes, calixarenes and cucurbiturils, and they can accommodate guest molecules in their cavities on the basis of shape and size complementariness. Among them, cucurbit[n]urils (CB[n]) are a relatively new class of macrocycles with versatile recognition properties and an ability to accommodate different organic guest molecules in aqueous solution with exceptionally high binding constants.