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Broadband-Light-Induced [2+2] Cycloaddition and Thermoinduced Cycloreversion-Powered Dynamic Molecular Crystals
Jiangbin Zhong1, Jingbo Sun1, Chao Chen1
1Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130021, P. R. China.
Angewandte Chemie (International Ed. in English)
|February 10, 2025
Summary
Dynamic molecular crystals harness visible light for mechanical work via [2+2] cycloaddition. This process stores energy in strained bonds, enabling reversible actuation triggered by heat, paving the way for solar-powered actuators.
Area of Science:
- Materials Science
- Photochemistry
- Crystallography
Background:
- Photomechanically responsive materials convert light to mechanical work.
- Molecular Solar Thermal Energy Storage (MOST) systems are explored for energy conversion.
- Photoinduced [2+2] cycloaddition in solids is underexplored for reversible actuation.
Purpose of the Study:
- To investigate broadband-light-induced [2+2] cycloaddition for energy storage and actuation in dynamic organic crystals.
- To demonstrate visible light as a trigger for energy storage and thermal energy release.
- To explore the potential of [2+2] cycloaddition for developing novel MOST architectures and crystal actuators.
Main Methods:
- Utilized a prototypical material, pyrenylvinylpyrylium tetrafluoroborate (1-PVPyL).
- Irradiated single crystals with UV, green, red, and broadband visible light to induce topochemical [2+2] cycloaddition.
- Observed crystal bending (actuation) and thermal cycloreversion for energy release.
Main Results:
- Demonstrated that 1-PVPyL undergoes [2+2] cycloaddition upon irradiation with visible light (532 nm, 620 nm, broadband).
- Observed single-crystal-to-single-crystal (SCSC) transformation leading to crystal bending.
- Showcased reversible actuation where stored energy is released via thermal cycloreversion.
Conclusions:
- Broadband visible light can induce [2+2] cycloaddition for energy storage and actuation in dynamic organic crystals.
- The [2+2] cycloaddition reaction offers potential for developing new MOST systems and visible-light-driven crystal actuators.
- This approach provides a versatile platform for harnessing solar energy for mechanical applications.
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