Photoswitchable macrocycles: Recent development of azobenzene, diarylethene, (Stiff-)stilbene or dihydroazulene-based photoswitchable macrocycles, for which conformation, dynamic, photo or thermal isomerization can be controlled by multiple photoswitching units, coordination-driven self-assembly, anion/cation binding or pH modulation, is reviewed, along with applications in encapsulation and release, in the reversible modulation of chemical, biological, electronic, fluorescent and chiroptical properties by light.

Abstract

Thanks to supramolecular interactions of macrocyclic compounds with their guest ions or molecules, macrocycles have found wide applications in molecular and chiral recognition, separation, transportation, molecular machines, and so on. Photoswitchable macrocycles are especially appealing and attracting more and more interest because the embedded molecular photoswitch enables dynamic control of molecular shape, conformation, and different properties by light, a non-invasive, remote and highly tunable stimulus. With available photochromic compounds, various photoswitchable macrocycles have been developed. In this review paper, we describe the recently reported photoswitchable macrocyclic compounds, with a focus on the control of the macrocyclic structure, dynamic, photo or thermal isomerization, as well as their applications on encapsulation and release of ionic or aromatic species, on the reversible modulation of chemical, biological, electronic, fluorescent and chiroptical properties by light.