Synthesis of bifunctional receptor for fluoride and cadmium based on calix[4]arene with thiourea moieties

A new calix[4]arene thiourea derivative bearing a benzothiazolyl moiety (L) was synthetized and characterized by single crystal X-ray, NMR and ESI-TOF. The binding ability of the bifunctional receptor towards several ions was investigated in acetonitrile by means of UV-Visible and NMR spectroscopy. The UV-Vis studies of receptor L demonstrated a stoichiometry of 1:1 for all ions studied. Also, recognize selectively F- and Cd2+ with a detection limit of 97 and 37 mu M, respectively. Also, H-1 NMR titration of receptor L indicated that both thiourea bridge and phenolic hydroxyl functional groups played a critical role in the binding of F- and Cd2+ ions. H-1 NMR spectrum showed that receptor L has a flattened-cone conformation in solution that changes to a cone conformation in the presence of fluoride while cadmium maintained the initial conformation. (C) 2017 Elsevier B.V. All rights reserved.