Recent Advances of Photoresponsive Supramolecular Switches

Photoresponsive supramolecular switches refer to these host-guest systems that can be reversibly shifted between different states by light stimuli. Such photoswitchable systems feature the presence of non-covalent bonding interactions with light-responsive moieties (e. g., azobenzene and stilbene, spiropyran and diarylethene, coumarin and anthracene), and have been applied in a variety of fields, such as drug delivery, tissue engineering and smart materials with the advantage of being able to operate cleanly and remotely in a spatiotemporally-controlled fashion. Alternating UV/visible light irradiation can reversibly regulate the binding affinity or assembly/disassembly of the systems. This minireview summarizes recent progress (2016 and after) on the development of photoswitchable host-guest systems, including the structural designs of these molecular switches and their applications in solution and solid states. Better knowledge of them is essential for the understanding of host-guest phenomena, molecular machines, and also for the preparation of novel applied materials in the future.