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 center dot 6H(2)O in ethanol. These receptors were characterized by elemental analyses, H-1 and C-13 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 1 H 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.