Nickel(II) and copper(II) complexes of allyl 2-(thiophen-2-ylmethylene) hydrazinecarbodithioate: synthesis, X-ray crystal structures, and theoretical study

We report allyl 2-(thiophen-2-ylmethylene)hydrazine-carbodithioate (HL) and its Ni(II) and Cu(II) complexes, [ML2]. The compounds were fully characterized by elemental analysis, IR, 1H-NMR, UV-Vis, and molar conductivity. The crystal structure analysis indicates that the metal is four-coordinate square planar and that a parallel stacking of the molecular planes is present in the crystals, with stacking distances of 3.642 and 3.676 A for the Ni(II) and Cu(II) complexes, respectively. Gas phase DFT computations indicate that the thione tautomeric form of the free ligand is more stable than the thiol form by 14.52 kJ mol–1. For HL and ML2, comparison between the computed and experimental data shows good agreement.