Synthesis, characterization, and electrochemical study of some novel, azo-containing Schiff bases and their Ni(II) complexes

Five novel azo-azomethine ligands with NN'OS coordination spheres were prepared by reaction of methyl-2-{N-(2'-aminoethane)}-amino-1-cyclopentenedithiocarboxylate (Hcden) with (E)-2-hydroxy-5-(phenyldiazenyl)benzaldehyde and its substituted derivatives and then the corresponding nickel(II) complexes were synthesized. The structures of ligands and the complexes were characterized by elemental analyses, IR, UV-Vis, H-1 NMR spectroscopy and cyclic voltammetry. The structures of (methyl 2-(2-((E)-2-hydroxy-5((E)-p-tolyldiazenyl)benzyli deneamino)ethylamino)cyclopent-1-enecarbodithioato)nickel(II) and (methyl 2-(2-((E)-5-((E)-(4-chlorophenyl)diazenyl)-2-hydroxybenzylideneamino)ethylamino)cyclopent-1-enecarbodithioato)-nickel(II) have been determined by X-ray crystallography. The X-ray results confirm that the geometry of the complexes are slightly distorted square-planar structures. The nickel(II) ions coordinate to two nitrogen atoms from the imine moiety of the ligand, a sulfur atom from the methyl dithiocarboxylate moiety and a phenolic oxygen atom. (C) 2013 Elsevier Ltd. All rights reserved.