Copper(II) and nickel(II) complexes with two new bis(thiosemicarbazone) ligands: Synthesis, characterization, X-ray crystal structures and their electrochemistry behavior

Abstract

Two new bis(thiosemicarbazone) ligands 2-[1-(2-{3-[2-({2-[(4-chloroanilino)carbothioyl]hydrazono}methyl)phenoxy]propoxy}phenyl)methylidene]-N1-(4-chlorophenyl)-1-hydrazinecarbothiamide (H2L1) and 2-[1-(2-{3-[2-({2-[(4-chloroanilino)carbothioyl]hydrazono}methyl)phenoxy]-2-hydroxypropoxy}phenyl)methylidene]-N1-(4-chlorophenyl)-1-hydrazinecarbothiamide (H3L2) were synthesized and characterized by FT-IR spectroscopy, 1H NMR spectroscopy and elemental analysis. Their nickel(II) and copper(II) complexes were prepared and characterized by UV–Vis spectroscopy, FT-IR spectroscopy, elemental analysis and single-crystal X-ray diffraction. Both ligands lose hydrazinic hydrogen atoms upon coordination and act as dianionic tetradentate donors. In [NiL1]·EtOH and [CuL1]·MeOH complexes metal centers are coordinated by two imine nitrogen atoms and two sulfur atoms with a distorted square planar coordination geometry. The geometrical distortion from square planar in the copper complex is greater than in the nickel complex. Cyclic voltammetry studies of Cu(II) and Ni(II) complexes in DMF show that all complexes able to stabilize low oxidation states of Cu(I) and Ni(I).