New supramolecular compounds: the complexes of nickel(II), copper(II), cobalt(II), cadmium(II) and zinc(II) with anti- [N-(4-aminophenyl)aza-15-crown-5]-4-(phenoxy)phenylglyoxime ligand

A new vic-dioxime ligand (1), bearing pendant an azacrown ether moiety and its soluble mononuclear cadmium(II), zinc(II), nickel(II), copper(II) and cobalt(II) complexes were obtained with the metal: ligand ratios of 1: 2 and 1:1. The structures of the ligand and its complexes were verified using Fourier transform infrared (FT-IR), ultraviolet-visible (UV-Vis), mass spectrometry (MS), H-1 and C-13 NMR techniques. More detailed information about the structure of the 1 was provided by the two-dimensional (2D) heteronuclear single quantum coherence and heteronuclear multiple bond correlation techniques. The complexation properties of the ligand 1 were studied in the presence of different cations such as Pb2+, Zn2+, Cu2+, Cr3+, Hg2+, Zn2+, Fe3+ and Al3+ by UV-Vis spectroscopy and H-1 NMR titration methods. All experimental results indicated that the new ligand acts as a selective compound only for Hg+2 cation. The redox behaviour of the complexes, were investigated by cyclic voltammetry at the glassy carbon electrode in 0.1 M tetrabutylamoniumtetrafluoroborate in dimethyl sulfoxide.