Hemicryptophane as a supramolecular host for the selective recognition and potential removal of halogenated pollutants

Chloro- and fluorocarbon compounds are toxic environmental pollutants that pose serious risks to both human health and ecosystems, highlighting the need for their efficient detection and removal. Although macrocyclic hemicryptophane (Hm) systems are well known for their role in catalysis and energy-related applications, their potential as host materials for pollutant capture remains insufficiently explored. In this study, the sensing capability and selectivity of hemicryptophane macrocycles toward various freon-type molecules, including CCl₄, CF₃Cl, CH₃Cl, CH₂Cl₂, CF₃Br C₂F₆, and CF₄, are investigated using computational methods. The host-guest complexes are analyzed through interaction energy calculations, natural bond orbital (NBO) analysis, frontier molecular orbital (FMO) studies, and interaction region indicator (IRI) analysis. The results demonstrate that the central cavity of selected hemicryptophane platform provides a favorable binding site for the studied freon-type molecules. The calculated interaction energies confirm the thermodynamic stability of the resulting complexes, while the HOMO–LUMO energy gaps (E H–L) provide insight into their electronic stability and reactivity. Among the studied compounds, chlorinated species, particularly CCl₄, CCl₃F, and CHCl₃, show the strongest interactions with the Hm platform, with interaction energies of -128.32, -109.37, and -92.65 kJ mol⁻¹, respectively. These interactions are predominantly governed by non-covalent forces. Overall, this study suggests that hemicryptophane-based systems have strong potential as host materials for the capture and removal of hazardous chloro- and fluorocarbon pollutants.