Chalcogen Bond-Assisted Iodine Adsorption from Water by Hydrophobic Receptor Se₄Me-PF₆

The removal of molecular iodine (I₂/I₃ ^-) from aqueous environments is of great importance due to its biological relevance and environmental concerns, particularly in nuclear waste management. Herein, a hydrophobic tetrapodal receptor Se₄Me-PF₆, which exhibits iodine adsorption from an aqueous phase via chalcogen bonding (ChB) interaction, is demonstrated. In the solution phase, NMR studies reveal that Se₄Me-PF₆ selectively recognizes iodide (I^-) over other anions. On the other hand, in the solid state, selenoimidazolium building units of Se₄Me-PF₆ facilitate self-assembly into a porous 1D supramolecular ChB framework, enabling efficient iodine adsorption. Consequently, Se₄Me-PF₆ has propelled the rapid adsorption of iodine, with a high kinetic rate of 2.10 × 10^{- 3} g mg^{- 1} min^{- 1}, while maintaining its effectiveness under competitive environmental conditions, including pH variations and the presence of interfering anions. Mechanistic investigations using XPS and density functional theory studies indicate that iodine capture occurs via a combination of ChB interactions and electrostatic forces provided by the selenoimidazolium motifs. Importantly, Se₄Me-PF₆ demonstrates its potential as a stationary phase for column-based iodine removal, highlighting its applicability in real-world scenarios. Thus, these findings offer a promising approach for developing iodine adsorbent materials.