Selective Inclusion of Fluoride within the Cavity of a Two-Wall Bis-calix[4]pyrrole

Abstract

We report what to our knowledge is the smallest bis-calix[4]pyrrole ( 2 ). It proved capable of trapping fluoride anions exclusively relative to other anions (Cl –, Br –, SCN –, NO 3 –, H 2 PO 4 –, HSO 4 –, SO 4 2–, and HP 2 O 7 3–; tetrabutylammonium salts), as confirmed by 1 H NMR spectroscopy (CDCl 3 ), X-ray diffraction analysis, DFT calculations, and molecular dynamics simulations. The F – selectivity is ascribed to the small size of the cavity in 2 .