Crown Ether Appended Amidopyrrole Clefts

Two new pyrrole amide–crown ether conjugates have been synthesised and their anion complexation properties studied in the absence and presence of stoichiometric quantities of sodium or caesium cations. Certain anions are sequestered by the metal cation in DMSO-d ⁶ (0.5% water), however, in one case a 4.7 fold increase in the fluoride affinity of the receptor was observed upon addition of caesium cations.