Highly soluble Ni(II) vic-dioxime complexes containing branched thioether with alkyl chains of different lengths: synthesis and characterization

vic-Dioxime ligands (LH₂) containing branched alkylthioether chains of different length have been prepared from (E,E)-dichloroglyoxime and corresponding thiol derivatives. Mononuclear Ni(II) complexes (5a–5c) were synthesized in ethanol by reacting NiCl₂ · 6H₂O with new ligands (4a–4c) in the presence of KOH. Branched alkylthioether moieties appended at the periphery of the oxime provide solubility for the vic-dioxime complexes in common organic solvents. The compounds have been characterized by elemental analyses, FT-IR and UV-Vis spectroscopy, ¹H- and ¹³C-NMR, and ESI-Mass spectrometry. While 5a and 5b are solid at room temperature, 5c is obtained as an orange viscous liquid. The thermal stabilities of the complexes were determined by thermogravimetric analysis.