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From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
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A halogen-bonding bis-triazolium rotaxane for halide-selective anion recognition
Benjamin R Mullaney1, Benjamin E Partridge, Paul D Beer
1Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Mansfield Rd, Oxford, OX1 3TA (UK).
Chemistry (Weinheim an Der Bergstrasse, Germany)
|November 21, 2014
Summary
This study reveals that halogen-bonding bis-triazolium carbazole receptors exhibit superior halide-binding compared to hydrogen-bonding analogues. A novel rotaxane host demonstrates selective bromide recognition in aqueous mixtures.
Area of Science:
- Supramolecular Chemistry
- Organic Chemistry
- Host-Guest Chemistry
Background:
- Acyclic receptors based on bis-triazolium carbazole scaffolds are investigated for anion binding.
- Halogen-bonding interactions offer a promising avenue for selective anion recognition.
- Comparing halogen-bonding versus hydrogen-bonding motifs is crucial for receptor design.
Purpose of the Study:
- To systematically evaluate the anion-binding properties of acyclic halogen- and hydrogen-bonding bis-triazolium carbazole receptors.
- To synthesize and characterize a novel rotaxane host incorporating a bis-iodotriazolium carbazole axle.
- To assess the halide selectivity and binding affinity of the rotaxane host.
Main Methods:
- Synthesis of bis-triazolium carbazole receptors with halogen-bonding (iodine) and hydrogen-bonding functionalities.
- Preparation of a mixed halogen- and hydrogen-bonding rotaxane host.
- (1)H NMR titration experiments in competitive aqueous solvent mixtures to determine anion binding.
Main Results:
- Halogen-bonding bis-iodotriazolium carbazole receptors showed significantly higher halide-binding potency than their hydrogen-bonding counterparts.
- A mixed halogen- and hydrogen-bonding rotaxane host was successfully synthesized.
- The rotaxane host exhibited selective halide recognition, with a strong affinity for bromide ions.
Conclusions:
- Acyclic halogen-bonding receptors are highly effective for anion binding, outperforming hydrogen-bonding analogues.
- The designed rotaxane host demonstrates efficient and selective recognition of bromide anions.
- This work advances the development of sophisticated supramolecular hosts for anion sensing and separation.
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