American Chemical Society
ol5b01866_si_009.cif (15.58 kB)

Calix[4]pyrroles with Shortest Possible Strap: Exclusively Selective toward Fluoride Ion

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posted on 2015-09-04, 00:00 authored by Ritwik Samanta, B. Sathish Kumar, Pradeepta K. Panda
Four new calix[4]­pyrroles with the shortest possible strap so far through ortho-linking of the aromatic unit have been synthesized, including a naphthalene-derived fluorescent receptor. They show exclusive selectivity toward the fluoride ion as confirmed by 1H NMR, isothermal titration calorimetry, and fluorescence spectroscopic study. Anion affinity could also be modulated further via functionalization at the strap. Computational analysis displays calix[4]­pyrroles binding to fluoride ion in a very unusual 1,3-alternate conformation where the anion resides on the opposite side of the strap.