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

•Five novel, azo-containing Schiff bases ligands were synthesized.•The molecular structures of the synthesized Ni(II) complexes were determined by the single crystal X-ray diffraction technique.•Molecular structures of the complexes are slightly distorted square-planar structures based on experimental studies.

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, 1H 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.

Graphical abstractFive novel azo-azomethine ligands with NN'OS coordination spheres were prepared and then the corresponding nickel(II) complexes were synthesized. The crystal structure analysis of nickel(II) complexes by using X-ray crystallography confirmed the complexes are slightly distorted square-planar structures.Figure optionsDownload full-size imageDownload as PowerPoint slide