Hexapodal Halogen-Bond Receptor for the Selective Liquid-Liquid Extraction of Iodide from Water

The continuous exploration of halogen-bond (XB) donor architectures unlocks vast opportunities in supramolecular chemistry. In this contribution, we report a newly designed hexapodal Hex-XB receptor by incorporating six XB donor sites integrated into a benzene platform. Hex-XB revels high selectivity toward iodide (I^-), with a large association constant of 3.3 × 10³ M^-1 in a competitive organo-aqueous medium. Most importantly, Hex-XB demonstrates quantitative iodide removal with an efficiency of ∼99.99% from 100% water via liquid-liquid extraction (LLE). Moreover, Hex-XB functions as an efficient triiodide (I₃^-) adsorbent, achieving an uptake capacity of up to 534.75 mg·g^-1 in water. Overall, this advanced receptor plays dual roles as a selective LLE─and adsorption─based extractant for iodide species (I^-, I₃^-) from pure water, opening a new avenue for the development of state-of-the-art multifunctional materials for water-contamination remediation.