Photoresponsive Dissipative Macrocycles Using Visible-Light-Switchable Azobenzenes
Esther Nieland1, Jona Voss1, Andreas Mix2
1Institut für Organische Chemie und Makromolekulare Chemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany.
Angewandte Chemie (International Ed. in English)
|September 27, 2022
Summary
Visible light triggers dynamic covalent imine assemblies. Researchers used a photoresponsive azobenzene building block to create diverse macrocycles, controlling their structure and assembly through light and amine choice.
Area of Science:
- Supramolecular Chemistry
- Organic Chemistry
- Photochemistry
Background:
- Dynamic covalent chemistry (DCvC) enables the construction of adaptive materials.
- Photoresponsive building blocks offer external control over molecular assembly.
- Azobenzene derivatives are well-established photoisomerizable units.
Purpose of the Study:
- To investigate the use of a fluorinated azobenzene building block in visible-light-driven dynamic covalent imine chemistry.
- To synthesize and characterize imine macrocycles using different amines and photoisomerization.
- To explore the control over macrocyclic structures and assembly states through light and chirality.
Main Methods:
- Synthesis of imine macrocycles using a fluorinated azobenzene and diamines (ethylenediamine, R,R-1,2-diaminocyclohexane).
- Photoisomerization studies using visible light irradiation.
- Structural characterization via 1H- and 19F-DOSY NMR, MALDI-MS, and UV/Vis spectroscopy.
Main Results:
- The azobenzene building block undergoes reliable geometric isomerism upon light irradiation.
- A simple amine yielded a polymeric state and a bowl-shaped macrocycle.
- A chiral amine led to a complex network of interconverting macrocycles with controlled cyclo-oligomerization.
Conclusions:
- Visible light can effectively control dynamic imine macrocycle formation and isomerism.
- Chirality plays a crucial role in directing the formation of diverse macrocyclic architectures.
- This work demonstrates a pathway for light-tunable supramolecular systems.
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