Chapter 8. Cucurbit[8]uril-based 2D and 3D Regular Porous Frameworks

For many years, studies on the generation of periodic or regular porosity and their properties and functions have been limited to insoluble solid-state materials. Self-assembly provides a straightforward strategy for the construction of water-soluble porous supramolecular organic frameworks (SOFs) from rationally designed rigid multitopic molecular components and cucurbit[8]uril (CB[8]). The process is driven hydrophobically by CB[8]-encapsulation-enhanced dimerization of the aromatic (CEBA) units that are appended to the multitopic molecules. By using this strategy, a variety of two-dimensional honeycomb-shaped, square, and rhombic SOFs have been constructed, some of which exhibit interesting absorption and sensing functions. From tetraphenylmethane- and [Ru(bipy)3]2+-derived precursors, three-dimensional diamondoid and cubic SOFs can also be generated. The diamondoid frameworks have been revealed to be open carriers for in situ loading and delivery of antitumor drugs, whereas [Ru(bipy)3]2+-cored frameworks are good porous photosensitizing materials for the enrichment of anionic polyoxometalate catalysts for new visible light–initiated reduction of proton to hydrogen gas. The progress well demonstrates the CB[8]-based CEBA strategy in constructing advanced water-soluble functional porous materials from symmetric preorganized aromatic precursors.