Halogen‐Bonding Heteroditopic [2]Catenanes for Recognition of Alkali Metal/Halide Ion Pairs. (20th December 2022)

• Record Type: Journal Article
• Authors: Tay, Hui Min; Tse, Yuen Cheong; Docker, Andrew; Gateley, Christian; Thompson, Amber L.; Kuhn, Heike; Zhang, Zongyao; Beer, Paul D.
• Is Part Of: Angewandte Chemie. Volume 135:Number 5(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-12-20
• Subjects: Halogen Bonding -- Heteroditopic Receptors -- Ion-Pair Recognition -- Mechanically Interlocked Molecules -- Solid–Liquid Extraction; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202214785
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: The first examples of halogen bonding (XB) heteroditopic homo[2]catenanes were prepared by discrete Na + template‐directed assembly of oligo(ethylene glycol) units derived from XB donor‐containing macrocycles and acyclic bis‐azide precursors, followed by a Cu I ‐mediated azide‐alkyne cycloaddition macrocyclisation reaction. Extensive 1 H NMR spectroscopic studies show the [2]catenane hosts exhibit positive cooperative ion‐pair recognition behaviour, wherein XB‐mediated halide recognition is enhanced by alkali metal cation pre‐complexation. Notably, subtle changes in the catenanes' oligo(ethylene glycol) chain length dramatically alters their ion‐binding affinity, stoichiometry, complexation mode, and conformational dynamics. Solution‐phase and single‐crystal X‐ray diffraction studies provide evidence for competing host‐separated and direct‐contact ion‐pair binding modes. We further demonstrate the [2]catenanes are capable of extracting solid alkali‐metal halide salts into organic media. Abstract : A series of halogen bonding heteroditopic [2]catenanes exhibit positive cooperative ion‐pair recognition behaviour, which has been exploited for the extraction of solid sodium or potassium halide salts into organic media. Changing the size of the component macrocycles dramatically influences the ion‐binding affinity, stoichiometry, and ion‐pair complexation mode of the [2]catenanes.