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

Abstract

The removal of molecular iodine (I2/I3-) from aqueous environments are of great importance due to their biological relevance and environmental concerns, particularly in nuclear waste management. In this work, we have demonstrated a hydrophobic tetrapodal receptor Se4Me-PF6, that exhibits iodine adsorption from an aqueous phase via chalcogen bonding (ChB) interaction. 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 DFT 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.