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

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–, NO3–, H2PO4–, HSO4–, SO4...