Conformational Chirality of Single-Crystal Covalent Organic Frameworks
Zhipeng Zhou1, Guohong Cai1, Zeyue Zhang1
1College of Chemistry and Molecular Engineering, Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, China.
Journal of the American Chemical Society
|November 29, 2024
Summary
Researchers developed a new method to create highly crystalline chiral covalent organic frameworks (COFs) by modifying their conformation. This breakthrough enhances their stability and tunable optical properties for advanced applications.
Area of Science:
- Materials Science
- Polymer Chemistry
- Crystallography
Background:
- Chiral organic polymers often exhibit limited crystallinity due to chiral units, hindering applications.
- Chiral covalent organic frameworks (COFs) face a similar challenge, balancing chirality and crystallization.
Purpose of the Study:
- To develop a general strategy for producing highly crystalline conformational chiral COFs.
- To demonstrate controllable stereochemistry and enhanced properties in these novel materials.
Main Methods:
- Breaking the meso conformation of achiral COFs to induce chirality.
- Utilizing chiral amino-acid derivative templates during synthesis.
- Characterizing thermodynamic and dynamic stability, and optical properties.
Main Results:
- Successfully produced a series of conformational chiral COFs with high crystallinity.
- Demonstrated excellent thermodynamic (200 °C annealing) and dynamic stability.
- Achieved tunable circular dichroism signals across UV-IR wavelengths with significant absorption dissymmetry (up to 300% change, max g_abs = 0.012).
Conclusions:
- The strategy enables the production of crystalline chiral COFs with controlled stereochemistry.
- Enhanced stability and tunable optical properties open new avenues for applications.
- This work provides a pathway for advancing crystalline chiral materials research.
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