Synthesis and structural and electrochemical characterization of novel macrocyclic vic-dioxime ligand and its mononuclear transition and nontransition metal complexes

The reaction of N-(4-aminophenyl)aza-15-crown-5 (1) with anti-chlorophenylglyoxime (2) produces a novel azacrown ether containing vic-dioxime, N-(4-aminophenyl)aza-15-crown-5-phenylglyoxime (LH_2). LH_2 reacts with Ni(II), Cu(II), Co(II), Cd(II), and Zn(II) ions to yield the mononuclear transition and nontransition metal complexes [M(LH)_2] (M = Ni and Cu), [M(LH)_2(H_2O)_2] (M = Co), and [M(LH)(H_2O)(Cl)] (M = Cd and Zn). The structural features of LH_2 were studied using several techniques including elemental analysis, Fourier transform infrared spectroscopy (FT-IR), ultraviolet visible (UV-Vis), mass spectrometry (MS), 1-dimensional (1D) ^1H-NMR and ^{13}CNMR, distortionless enhancement by polarization transfer (DEPT) 2-dimensional (2D) heteronuclear single-quantum coherence (HSQC), and heteronuclear multiple-bond correlation (HMBC) techniques. The structures of the complexes were confirmed by elemental analyses and with the use of magnetic susceptibility measurements, MS, UV-Vis, FT-IR, ^1H-NMR, and ^{13}C-NMR techniques. The redox behaviors of the ligand and its complexes were verified with cyclic voltammetry (CV) at a glassy carbon (GC) electrode in 0.1 M tetrabutylammoniumtetrafluoroborate (TBATFB) in dimethyl sulfoxide (DMSO). -

Keywords: vic-Dioxime, azacrown ether, transition metal complexes, mass spectroscopy, cyclic voltammetry