Dynamic Transformation between Covalent Organic Frameworks and Discrete Organic Cages
Zhen Shan1, Xiaowei Wu1, Bingqing Xu1
1Key Laboratory for Soft Chemistry and Functional Materials of Ministry of Education, School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu 210094, China.
Journal of the American Chemical Society
|December 9, 2020
Summary
Dynamic covalent chemistry enables structural transformation between covalent organic frameworks (COFs) and cages. Borate and imine bonds facilitate reversible COF-to-cage and cage-to-COF conversions, yielding stable porous materials.
Area of Science:
- Materials Science
- Organic Chemistry
- Supramolecular Chemistry
Background:
- Covalent organic frameworks (COFs) are crystalline porous polymers with diverse applications.
- Discrete molecular cages offer unique host-guest properties.
- Transformations between these two classes of materials remain challenging.
Purpose of the Study:
- To develop a novel strategy for interconverting COFs and cages.
- To utilize dynamic covalent chemistry (DCC) for controlled structural transformations.
- To explore the thermodynamic stability of resulting structures.
Main Methods:
- Employing dynamic covalent chemistry (DCC) via linker exchange reactions.
- Utilizing borate and imine bonds as reversible linkages.
- Conducting self-sorting experiments to determine thermodynamic products.
Main Results:
- Successfully demonstrated reversible transformations between COFs and cages for the first time.
- Achieved COF-to-cage transformation using borate linkages.
- Achieved cage-to-COF transformation using imine linkages.
- Identified borate cages and imine COFs as thermodynamically stable end products.
Conclusions:
- Established a DCC-induced linker exchange strategy for COF-cage interconversion.
- Bridged the gap between discrete molecular cages and polymeric COFs.
- Expanded the understanding of porous materials science and dynamic covalent chemistry.
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