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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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Modulating Chalcogen Bonding and Halogen Bonding Sigma-Hole Donor Atom Potency and Selectivity for Halide Anion
Andrew Docker1, Charles H Guthrie1, Heike Kuhn1
1Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, UK.
Angewandte Chemie (International Ed. in English)
|July 23, 2021
Summary
New anion receptors with tunable electronic properties show enhanced binding affinity for anions. Modifications significantly increase potency, offering precise control over molecular recognition for halides.
Area of Science:
- Supramolecular Chemistry
- Organic Chemistry
- Materials Science
Background:
- Anion recognition is crucial in biological and chemical processes.
- Developing selective and potent anion receptors remains a challenge.
- Chalcogen bonds (ChB) and halogen bonds (XB) offer promising non-covalent interactions for receptor design.
Purpose of the Study:
- To design and synthesize novel acyclic anion receptors incorporating ChB and XB donors.
- To investigate the effect of electronic modulation on anion binding affinity and selectivity.
- To explore the potential of these receptors in sensing and separation applications.
Main Methods:
- Synthesis of a series of neutral 3,5-bis-triazole pyridine based receptors.
- Systematic variation of aryl substituents to modulate electronic properties.
- Anion binding studies using techniques like NMR titration and isothermal titration calorimetry.
- Linear free energy relationship analysis to correlate structure and binding.
Main Results:
- Receptors with electron-withdrawing perfluorophenyl groups showed significantly enhanced chloride anion affinity (up to 30-fold for ChB, 8-fold for XB).
- Tellurium-based ChB receptors demonstrated high sensitivity to electronic environments, with binding strength and selectivity tunable by aryl group modification.
- Enhanced selectivity for lighter halides was observed with increasing electron-withdrawing ability.
Conclusions:
- Electronic modulation of sigma-hole donor atoms is a powerful strategy for enhancing anion receptor potency.
- ChB and XB receptors based on the described scaffold offer tunable affinity and selectivity for halide anions.
- These findings open avenues for designing advanced materials for anion sensing and separation.
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