Novel vic-dioxime ligand containing calix[4]pyrrole moiety: synthesis, characterization, anion binding studies and complexation with Ni(II)

A new vic-dioxime functionalized calix[4]pyrrole was synthesized from anti-chloroglyoxime and 4-aminophenyl-calix[4]pyrrole at room temperature. The Ni(II) complex has been prepared by reacting the ligand with NiCl2·6H2O in ethanol. These receptors were characterized by elemental analyses, 1H and 13C NMR spectra, IR and mass spectra. Electrochemical properties of the ligand, and its Ni(II) complex were investigated in CH2Cl2 solution by cyclic voltammetry at 100 mV s−1 scan rate. Anion-binding studies were carried out using UV–Vis, and 1H NMR titrations, revealed that the Ni(II) complex exhibits selective recognition toward F− over other anions. The selectivity for F– among the halides is attributed mainly to the hydrogen-bond interaction of the receptor with F–. Receptor showed colour change from red to brown in the presence of tetrabutylammonium fluoride (TBAF) with 1:2 stoichiometry.