Ionic Liquid-Accelerated Growth of Covalent Organic Frameworks with Tunable Layer-Stacking
Lifeng Deng1, Sihao Zhu1, Qingyang Zou1
1Hunan Key Laboratory of Micro & Nano Materials Interface Science, Department College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, China.
Angewandte Chemie (International Ed. in English)
|June 28, 2024
Summary
Researchers developed a "key-cylinder lock mimic" strategy using ionic liquids (ILs) to control layer stacking in two-dimensional covalent organic frameworks (2D COFs). This method enables tunable stacking modes and faster synthesis of crystalline COF powders.
Area of Science:
- Materials Science
- Nanotechnology
- Supramolecular Chemistry
Background:
- Layer-stacking in 2D COFs dictates crucial properties like pore structure and functionality.
- Achieving controlled layer stacking without complex methods is a significant challenge in COF synthesis.
Purpose of the Study:
- To develop a facile strategy for tunable layer-stacking in 2D COFs.
- To investigate the role of ionic liquids (ILs) in controlling COF assembly.
Main Methods:
- A
- key-cylinder lock mimic
- strategy utilizing ionic liquids (ILs) was employed for 2D COF synthesis.
- Systematic variation of IL properties (polarity, molecular size) to influence COF stacking.
- Mechanistic studies to elucidate the role of ILs in directing layer assembly.
Main Results:
- Staggered (AB) stacking COFs were exclusively formed with ILs of symmetric polarity and matching molecular size.
- Eclipsed (AA) stacking COFs were obtained with other ILs, consistent with previous reports.
- A confined interlocking effect (CIE) involving IL anions and cations was identified as the mechanism for AB stacking.
- The strategy significantly accelerated the production rate of crystalline COF powders (e.g., 30 minutes for COF-TAPT-Tf@BmimTf2N) under mild conditions.
Conclusions:
- Ionic liquids are effective in tailoring the layer-stacking modes of 2D COFs.
- The
- key-cylinder lock mimic
- strategy offers a simple yet powerful approach to control COF structure.
- This work opens avenues for exploring stacking mode-dependent applications of 2D COFs.
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