Halogen Bonding Heteroditopic Materials for Cooperative Sodium Iodide Binding and Extraction

A series of novel heteroditopic halogen bonding (XB) receptor functionalised silica based materials, containing mono‐ and bis‐iodotriazole benzo‐15‐crown‐5 groups are investigated for the cooperative binding and extraction of sodium halide ion‐pair species from aqueous solution. Characterisation of the XB materials by CHN elemental analysis, (13)C CP/MAS NMR and ATR‐FTIR spectroscopies confirms and quantifies the successful incorporation of the ion‐pair receptor frameworks to the silica material. ICP‐MS solid‐liquid extraction studies demonstrate the bidentate XB functionalised material is capable of NaI extraction from water. Importantly, cooperative XB‐mediated sodium halide ion‐pair binding is determined to be crucial to the material's extraction capabilities, impressively demonstrating a two‐fold enhancement in sodium iodide extraction efficiency relative to a heteroditopic hydrogen bonding receptor functionalised silica material analogue.