Transition metal complexes with thiosemicarbazide-based ligands. Part 36. Complexes of iron(III), nickel(II), cobalt(II) and copper(II) with 2-acetylpyridine S-methylisothiosemicarbazone

Abstract

The reaction of ethanolic solutions of 2-acetylpyridinc S-methylisothiosemicarbazone with different salts of iron(II, III), nickel(II), cobalt(II), and copper(II) gave mono(ligand), and in the case of iron and nickel also bis(ligand) complexes of different compositions, in which the ligand is coordinated either in the neutral, monoanionic, or mixed form. A bidentate coordination of the neutral and a tridentate coordination of the monoanionic form were postulated. The molar conductivities and IR spectra indicate that, in addition to the organic ligand, the acid anions are in some cases involved in the coordination. The bis(ligand) complexes have an octahedral geometry, whereas for the mono(ligand) complexes a tetra-or penta-coordination is supposed. Magnetic measurements showed that the title ligand, even in the presence of iodide, can stabilize the higher oxidation states of iron and copper.