Ni(II) complexes with [N3O] schiff base ligands bearing S-methylisothiosemicarbazide unit: design, synthesis and structure

Synthesis, structure and physico-chemical investigation of four new nickel(II) complexes with [N3O] chelate tetradentate ligands are described. They were obtained by template condensation of mono-S-methylisothiosernicarbazone of acetylacetone or 1-phenyl-butane-1,3-dione with bifunctional carbonyl compounds such as anthranil aldehyde or 4-amino-3-penten-2-one. Square-planar complexes were obtained as only products with good yield and were fully characterised by El MS, NNIR (H-1, C-13) spectroscopy, elemental analysis, and, in the case of three complexes, by X-ray investigation. A Cambridge Structural Database surveys on related square-planar Ni(II) complexes was also included, showing a small but significant correlation between Ni-O distances and O-Ni-N angles