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06:44
From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
69.3K
Lithium halide ion-pair recognition with halogen bonding and chalcogen bonding heteroditopic macrocycles
Yuen Cheong Tse1, Andrew Docker1, Zongyao Zhang1
1Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK. paul.beer@chem.ox.ac.uk.
Chemical Communications (Cambridge, England)
|April 20, 2021
Summary
Researchers developed new macrocyclic receptors for recognizing lithium halide ion-pairs. These receptors show selective binding, with potential applications in recovering lithium salts.
Area of Science:
- Supramolecular Chemistry
- Organic Chemistry
- Materials Science
Background:
- Halogen and chalcogen bonding are non-covalent interactions crucial for molecular recognition.
- Lithium halide (LiX) ion-pairs present challenges in selective binding and separation.
- Macrocyclic receptors offer tailored cavities for specific ion-pair complexation.
Purpose of the Study:
- To design and synthesize novel heteroditopic macrocyclic receptors incorporating phenanthroline units.
- To investigate the cooperative binding of lithium halide ion-pairs using halogen bonding and chalcogen bonding motifs.
- To evaluate the selectivity and affinity of these receptors for different lithium halides.
Main Methods:
- Synthesis of phenanthroline-based macrocycles with sigma-hole donor groups (iodo- and telluromethyl-triazoles).
- Quantitative 1H NMR ion-pair titration experiments in a mixed solvent system (CDCl3:CD3CN).
- Preliminary solid-liquid extraction experiments to assess practical application.
Main Results:
- Cooperative recognition of lithium halide ion-pairs was observed, with lithium cation binding enhancing halide anion recognition.
- The halogen bonding receptor showed exclusive binding of lithium chloride (LiCl).
- The chalcogen bonding receptor demonstrated selectivity for lithium iodide (LiI) over lithium bromide (LiBr).
Conclusions:
- Cooperative sigma-hole interactions in macrocyclic receptors enable selective ion-pair recognition.
- Tailoring sigma-hole donor motifs (halogen vs. chalcogen bonding) allows for distinct halide anion selectivity.
- These findings highlight a promising strategy for lithium salt recovery through advanced supramolecular chemistry.
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