Construction of Covalent Organic Frameworks with Crown Ether Struts
Shuhao An1, Qing Xu2, Zhihui Ni3
1School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai, 200237, P. R. China.
Angewandte Chemie (International Ed. in English)
|February 18, 2021
Summary
New covalent organic frameworks (COFs) incorporate flexible crown ethers into their backbones, achieving high surface areas and crystallinity for effective alkali metal ion separation, particularly K+ and Cs+.
Area of Science:
- Materials Science
- Supramolecular Chemistry
- Separation Science
Background:
- Crown ethers are macrocyclic molecules with flexible structures, rarely used in covalent organic frameworks (COFs).
- Constructing COFs with high crystallinity and surface area using flexible units like crown ethers presents a significant challenge.
Purpose of the Study:
- To synthesize novel covalent organic frameworks (COFs) utilizing crown ethers as backbone components.
- To investigate the application of these crown ether-based COFs in alkali metal ion separation.
Main Methods:
- Synthesis of two new COFs incorporating 18-crown-6 and 24-crown-8 units as backbones.
- Characterization of COF properties including surface area, crystallinity, and chemical stability.
- Evaluation of alkali metal ion (K+, Cs+) binding capabilities.
Main Results:
- Both synthesized COFs exhibited high surface areas, good crystallinity, and excellent chemical stability.
- The COFs demonstrated remarkable binding affinity for K+ and Cs+ ions, attributed to the size-fit effect of the crown ether units.
- Successful integration of crown ethers as backbone units in COF construction was achieved.
Conclusions:
- Flexible crown ether units can be effectively integrated as backbones in COFs, overcoming previous fabrication challenges.
- Crown ether-based COFs show significant potential for selective alkali metal ion separation.
- This research highlights the value of crown ethers in designing advanced COFs for separation applications.
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