Photoresponsive Dissipative Macrocycles Using Visible-Light-Switchable Azobenzenes

Angew Chem Int Ed Engl. 2022 Nov 25;61(48):e202212745. doi: 10.1002/anie.202212745. Epub 2022 Oct 26.

Abstract

Visible light can be used to shift dynamic covalent imine assemblies out of equilibrium. We studied a fluorinated azobenzene building block that reliably undergoes geometric isomerism upon irradiation. The building block was used in combination with two different amines, ethylenediamine and R,R-1,2-diaminocyclohexane, to create a library of imine macrocycles. Whereas the simple amine can be used to access a polymeric state and a defined bowl-shaped macrocycle, the chiral amine gives access to a rich network of macrocycles that undergo both isomerisation as well as interconversion between different macrocyclic species, thereby allowing for control over the number of monomers involved in the cyclo-oligomerization; 1 H- and 19 F-DOSY NMR, MALDI-MS measurements, and UV/Vis spectroscopy were used to study the processes.

Keywords: Dynamic Covalent Chemistry; Imines; Photochemistry; Self-Assembly; Supramolecular Chemistry.