3D Covalent Organic Frameworks of Interlocking 1D Square Ribbons
Yuzhong Liu1, Christian S Diercks1, Yanhang Ma2
1Department of Chemistry, University of California-Berkeley; Materials Sciences Division, Lawrence Berkeley National Laboratory ; and Kavli Energy NanoSciences Institute , Berkeley , California 94720 , United States.
Journal of the American Chemical Society
|December 12, 2018
Summary
Researchers created a novel 3D woven covalent organic framework (COF-500) using interlocked 1D organic ribbons. This mechanically interlocked structure exhibits dynamic pore size changes in response to stimuli.
Area of Science:
- Materials Science
- Supramolecular Chemistry
- Nanotechnology
Background:
- Covalent Organic Frameworks (COFs) are crystalline porous polymers with tunable structures.
- Mechanical entanglement offers a new strategy for designing dynamic and responsive materials.
- Previous COFs often lack inherent dynamic capabilities for structural manipulation.
Purpose of the Study:
- To describe a new mode of mechanical entanglement in extended structures.
- To synthesize and characterize a 3D woven covalent organic framework (COF-500) with interlocked 1D ribbons.
- To investigate the dynamic behavior and responsiveness of the synthesized COF.
Main Methods:
- Synthesis of a metalated COF (COF-500-Cu) via imine condensation of aldehyde-functionalized Cu(PDB)2PO2Ph2 complexes and tetratopic ETTBA linkers.
- Demetalation of COF-500-Cu to yield the mechanically interlocked COF-500.
- Characterization using nitrogen adsorption and solid-state photoluminescence studies to probe structural dynamics.
Main Results:
- Successful synthesis of a crystalline porous metalated COF (COF-500-Cu) with pts topology.
- Demetalation revealed COF-500, where 1D square ribbons are held by mechanical interlocking, enabling collective movement.
- COF-500 demonstrated dynamic pore size changes, reversibly narrowing and reopening upon exposure to tetrahydrofuran vapor, while maintaining structural integrity.
Conclusions:
- A novel 3D woven covalent organic framework (COF-500) based on mechanically interlocked 1D ribbons has been developed.
- The material exhibits dynamic structural changes and reversible pore modulation due to mechanical entanglement.
- This work introduces a new paradigm for designing responsive materials through controlled mechanical interlocking.
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