Abstract:Cucurbiturils are a series of pumpkin-shaped macrocyles obtained from an acid-catalyzed condensation reaction of glycoluril and formaldehyde, they can bind with gases, small molecules and positive charged guests, and have been widely used in the fields of separation, catalysis, pharmaceutical, interlocked molecules, supramolecular architectures and etc. Recently, our group have synthysized a new class of Helianthus-like cucurbituril analogues (TD[n]) using the condensation of glycoluril-like propanediurea (2,4,6,8-tetraazabicyclo[3.3.1]nonane-3,7-dione, TD) or its derivatives with formaldehyde. Compared with glycoluril, substituents can be introduced more easily on the central methylene position of TD and have less influence upon the cucurbituril-forming cyclization. It should be noted that the value of n in cucurbituril family is reduced to 4 for the first time and TD[4] is of smaller cavity than ever. Moreover, some TD[4]s bind selectively to metal ions and some TD[5]s bind strongly with protonated amines in portal binding mode, and a series of TD[n]-based supramolcular polymers have consequently been set up, which would lay a solid foundation for their future applications in areas such as supramolecular chemistry.