Mononuclear nickel(II) and copper(II) complexes with Schiff base ligands derived from 2,6-diformyl-4-methylphenol and S-methylisothiosemicarbazones

Four new square-planar Ni(II) and Cu(II) complexes with [N2O2] binding system were synthesized by metal-directed condensation of 2,6-diformyl-4-methylphenol with benzoyl or acetylacetone mono-S-methylisothiosemicarbazone. Only mononuclear “one-armed” complexes were obtained as a consequence of the different reactivity of the two carbonyl groups in the hydroxydialdehyde. The complexes were characterized by elemental analysis, EI MS and UV–Vis spectroscopy. The structural assignment was confirmed by X-ray diffraction analysis and NMR spectroscopy, for the Ni(II) complexes, and by ESR spectroscopy and magnetic measurements, for the Cu(II) complexes.