Applications of pillarenes, an emerging class of synthetic macrocycles

Synthetic macrocycles, a typical type of building block for molecular recognition and self-assembly, are crucial to supramolecular chemistry and materials science. Since 2008, a new generation of synthetic macrocyclic hosts, pillarenes and their abundant derivatives, which consist of hydroquinone units linked by methylene bridges at 2,5-positions, have been the focus of much research. Numerous studies on their host-guest properties and the fabrication of supramolecular assemblies have demonstrated that pillarenes and their derivatives possess many advantages that facilitate their applications in many research fields. Herein we summarize and classify the applications of pillarenes in terms of artificial transmembrane channels, controlled delivery systems, dispersion of carbon hybrid materials, extraction and absorption, liquid crystals, metal-organic frameworks, sensing and detection, stabilization of nanoparticles (Au/Ag/CdTe), and other typical biological applications. We also provide an overview of future developments in pillarene chemistry.