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Covalent Post-assembly Modification Triggers Structural Transformations of Borromean Rings.
Wen-Xi Gao1, Hui-Jun Feng1, Yue-Jian Lin1
1Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, State Key Laboratory of Molecular Engineering of Polymers, Department of Chemistry , Fudan University , Shanghai 200433 , P. R. China.
Journal of the American Chemical Society
|May 24, 2019
Summary
Researchers demonstrate novel supramolecular transformation cascades using ligand exchange and Diels-Alder reactions. These reactions enable controlled linking, unlinking, and modification of Borromean rings (BRs) through triggered topological changes.
Area of Science:
- Supramolecular Chemistry
- Organic Chemistry
- Materials Science
Background:
- Borromean rings (BRs) are complex interlocked structures with unique topological properties.
- Controlling the assembly and disassembly of supramolecular architectures is crucial for developing advanced materials.
Purpose of the Study:
- To develop a new family of template-free, tetrazine-edged Borromean rings (BRs).
- To investigate concentration-dependent linking and unlinking mechanisms for these BRs.
- To explore supramolecular structural transformations using inverse electron-demand Diels-Alder (IEDDA) reactions for post-assembly modification.
Main Methods:
- Ligand exchange reactions for BR construction.
- Observation of concentration-dependent linking and unlinking of BRs.
- Inverse electron-demand Diels-Alder (IEDDA) reactions for triggered transformations.
Main Results:
- Successfully synthesized template-free, tetrazine-edged BRs.
- Demonstrated concentration-dependent control over BR linking and unlinking.
- Achieved post-assembly modification of Borromean precursors via IEDDA reactions.
- Observed controlled topological transformations, including unlinking, induced by steric changes from IEDDA reactions.
Conclusions:
- Supramolecular transformation cascades offer a versatile platform for constructing and manipulating complex architectures.
- IEDDA reactions provide a powerful tool for triggering topological changes and post-assembly modifications in Borromean ring systems.
- The developed system allows for precise control over supramolecular topology through external stimuli.
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