Metal-ligated pillararene materials: From chemosensors to multidimensional self-assembled architectures

Combination of pillararenes and metal ligated self-assembled materials has appealed much attention due to their significant enrichment of current hybrid materials with various physicochemical properties and functions. The introduction of pillararene cavity would contribute a large choice of different sized and shaped nanopores to mesoporous metal ligated materials, leading to the construction of multiple porous systems and spatially limited microenvironment inside. Additionally, electron-rich pillararene cavity is tunable, granting metal ligated pillararene materials with the possibility of differentiating diverse guest molecules. In this review, we thoroughly describe pillararene-based metal ligated materials by focusing on (1) the role of pillararenes as the ligands, e.g., the primary and secondary ligands, (2) the relationship between metal cations and pillararene-based systems, (3) the construction of advanced self-assembled materials such as vesicles, supramolecular polymers, mechanically-interlocked molecules, metal–organic frameworks, and metal–organic gels, and (4) their applications to e.g., detection and removal of heavy metal ions and organic dyes, sensor array, catalysis, as well as drug delivery and biomedicine. Major characterization methods and perspectives of future research directions are also included to make this review more readable and helpful for different researchers in this area.