Superphanes: Old Yet New Binding–Agents for Highly Selective Recognition of Fluoride by Size–Sieving Effect

Superphanes, namely percyclophanes, have been widely investigated for the sake of their aesthetically pleasing structures with high symmetry, intriguing physical and chemical properties and synthetic challenges. Nonetheless, the host–guest chemistry of superphanes remains to be an unmet challenge. Herein, we delineate the design, preparation, characterization, and host–guest chemistry of an unprecedented superphane 15, which was evidenced by mass spectroscopy, NMR spectroscopy, X–ray crystallography, and DFT calculations. 15 features six bridges between two benzene planes, up to 18 C_sp–H hydrogen–bonding donors well–distributed around the near–closed inner cavity in three dimensions. These allow 15 to exhibit exclusive selectivity towards F^– against Cl^–, Br^–, I^–, N₃^–, SCN^–, NO₃^–, ClO₄^–, SO₄^2– and HP₂O₇^3– due to the size–sieving effect. This contribution opens up new opportunities for design and synthesis of new supramolecular hosts for anions of interest with high selectivity.