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Halide-Controlled Extending-Shrinking Motion of a Covalent Cage
Anna B Aletti1, Ana Miljkovic2, Lucio Toma2
1School of Chemistry , Trinity College Dublin, The University of Dublin , 152-160 Pearse Street , Dublin 2 , Ireland.
The Journal of Organic Chemistry
|March 19, 2019
Summary
Flexible covalent cages exhibit controllable extending-shrinking motion in response to halide anions. This conformational change, driven by anion binding, allows for reversible switching between two distinct cage structures.
Area of Science:
- Supramolecular Chemistry
- Organic Chemistry
- Materials Science
Background:
- Covalent cages are molecular structures with potential applications in sensing and catalysis.
- Understanding the dynamic behavior of these cages is crucial for designing responsive materials.
Purpose of the Study:
- To demonstrate a covalent cage with a flexible framework capable of conformational changes.
- To investigate the role of halide anions in controlling the cage's structure and dynamics.
Main Methods:
- Synthesis and characterization of a novel flexible covalent cage.
- Experimental studies using halide anions (e.g., AgNO3/TBAC) to induce conformational changes.
- Computational investigations to analyze energy barriers and conformational pathways.
Main Results:
- The covalent cage exhibits a flattened conformation without halide anions, with a compressed cavity.
- Halide encapsulation induces a significant rearrangement, extending the cavity and staggering the platforms.
- The cage undergoes reversible conformational switching between shrunk and expanded states upon alternating chemical stimuli.
- Computational studies revealed low activation barriers for the conformational changes and quantified energy differences between states.
Conclusions:
- Flexible covalent cages can be dynamically controlled by halide anions.
- The observed extending-shrinking motion and reversible switching demonstrate the potential for stimuli-responsive molecular materials.
- Computational insights provide a deeper understanding of the mechanism governing the cage's conformational dynamics.
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