Dynamic covalent macrocycles, known for their reversible bond formation and adaptability, have presented challenges in achieving precise topological control. By leveraging photoswitches, this work demonstrated the light-controlled bidirectional transformation between macrocycles and linear structures. The photoswitchable dynamic covalent macrocycles have been successfully utilized to modulate metal ion recognition and mechanically interlocked molecules (MIMs), including rotaxanes and catenanes.

In a recent study published in Angewandte Chemie International Edition, the researcher group led by Prof. YOU Lei from Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences,  reported a novel platform for photoswitchable topological regulation of dynamic covalent macrocycles. The strategies and results should be appealing to endeavors in molecular recognition, dynamic assemblies, molecular machines, and intelligent materials.

Researchers established photoswitchable topological control of dynamic covalent macrocycles, achieved by introducing light-induced dynamic covalent reactions (DCRs). Enabling reversible transformations between dithioacetal-based macrocycles and their linear structures. Compared to previous approaches, this strategy represents a novel and precise mechanism for manipulating molecular topology.

The light-regulated molecular recognition of alkali metal ions, including Li^+, Na⁺, and K⁺ was realized. By altering the topology of the macrocycles, the tunable binding affinities and selective recognition was achieved. Unlike traditional host-guest systems, this process relied on topological transformation, marking a unique contribution to molecular recognition research.

This study extends the light-responsive system to the construction of (MIMs), such as rotaxanes and catenanes. Through light-induced macrocycle transformation, the researchers developed a controllable method for the assembly and disassembly of interlocked structures, demonstrating a significant advance in molecular machines and smart materials.

Photoswitchable topological regulation of dynamic macrocycles and their assemblies (Image by Prof. YOU Lei’s group)

Contact:
Prof. YOU Lei

Fujian Institute of Research on the Structure of Matter

Chinese Academy of Sciences

Email: lyou@fjirsm.ac.cn