Calix[4]arene based neutral receptor for dihydrogen phosphate anion

Abstract A series of novel calix[4]arene hydrazone and semicarbazone based neutral receptors have been synthesized and characterized by IR, UV–vis, and NMR spectroscopies. The preliminary UV–vis and 1 H NMR titration experiments revealed that 25,26,27,28-tetrapropoxycalix[4]arene tetra-semicarbazone can recognize H 2 PO 4 − through a 1:1 binding-stoichiometry in preference over other anions (Cl − , Br − , I − , HSO 4 − , ClO 4 − , and CH 3 COO − ).