Anion receptors based on ureido-thiacalix[4]arenes

The regioselective ipso-nitration of tert-butylthiacalix[4]arene-tetrasulfone was used for the construction of thiacalixarene derivatives bearing one or two arylureido functions on the upper rim. The preorganization of ureido units using the thiacalix[4]arene moiety as a molecular scaffold leads to novel anion receptors with good complexation ability toward selected anions of various geometry (halides, carboxylates, HSO₄⁻, H₂PO₄⁻, NO₃⁻, CN⁻) in organic solvents.