Synthesis, characterization, photoluminescence and electrochemical studies of NiII, CuII, ZnII, CdII and PdII complexes of the bidentate S-hexyl-β-N-(2-thienyl)methylenedithiocarbazate ligand

Divalent metal complexes of empirical formulation [ML2] (where M(II) = Ni, Cu, Zn, Cd and Pd; L = anionic form of the 2-thiophenecarboxaldehyde Schiff base of S-hexyldithiocarbazate) have been synthesized and characterized by physico-chemical techniques. Magnetic and spectroscopic data give support to a square-planar coordination geometry for these complexes with the exception of the ZnII and CdII species. The single crystal structures of the [NiL2] and [CuL2] complexes have been determined by X-ray diffraction analysis. In both the structurally characterized complexes the uninegatively charged bidentate ligands coordinate the metal (II) ion via the azomethine nitrogen and the thiolate sulfur atoms in a trans-planar configuration. The electrochemical properties of the Cu(II) complex have been studied by cyclic voltammetry. The voltammogram shows quasi-reversible, one electron redox process. Metal-mediated fluorescence quenching is observed on complexation of HL with all metal ions.

In this study, the N,S-Schiff base ligand and various divalent metal complexes were prepared and characterized. Molecular structures of Cu(II) and Ni(II) complexes were determined by single crystal X-ray diffraction studies.Figure optionsDownload as PowerPoint slide