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Updated: Aug 24, 2025
From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
Anti-Hofmeister Anion Selectivity via a Mechanical Bond Effect in Neutral Halogen-Bonding [2]Rotaxanes
Andrew Docker1, Yuen Cheong Tse1, Hui Min Tay1
1Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK.
Abstract:
Exceptionally strong halogen bonding (XB) donor-chloride interactions are exploited for the chloride anion template synthesis of neutral XB [2]rotaxane host systems which contain perfluoroaryl-functionalised axle components, including a remarkably potent novel 4,6-dinitro-1,3-bis-iodotriazole motif. Halide anion recognition properties in aqueous-organic media, determined via extensive 1 H NMR halide anion titration experiments, reveal the rotaxane host systems exhibit dramatically enhanced affinities for hydrophilic Cl- and Br- , but conversely diminished affinities for hydrophobic I- , relative to their non-interlocked axle counterparts. Crucially, this mechanical bond effect induces a binding selectivity which directly opposes Hofmeister bias. Free-energy analysis of this mechanical bond enhancement demonstrates anion recognition by neutral XB interlocked host systems as a rare and general strategy to engineer anti-Hofmeister bias anion selectivity in synthetic receptor design.
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