Structural studies of metal complexes of 2-pyridineformamide N(4)-methylthiosemicarbazone

Abstract

Reduction of 2-cyanopyridine by sodium in dry methanol in the presence of N(4)-methylthiosemicarbazide produces 2-pyridineformamide N(4)-methylthiosemicarbazone, HAm4M. In the crystals of [Ni(HAm4M) 2](ClO 4) 2·2H 2O, [Zn(Am4M)OAc] 2 and [Cd(HAm4M)Cl 2]·DMSO the major ligand coordinates via its pyridyl nitrogen, imine nitrogen and sulfur atoms, the last of which forms a thione in the neutral ligand HAm4M and a thiolato group in (Am4M) −. Both the acetato ligands in [Zn(Am4M)OAc] 2 are bis-monodentate bridges, which is unique among acetato-bridged binuclear complexes of thiosemicarbazones of this type. As in the complexes of other 2-pyridineformamide thiosemicarbazones, hydrogen bonds play an important role in these compounds. As well as by X-ray diffractometry, the new compounds were characterized by elemental analysis, FAB mass spectrometry and IR spectroscopy; in the case of the nickel(II) complex, by electronic spectroscopy and by molar conductivity and magnetic susceptibility measurements; and in the case of the zinc(II) and cadmium(II) complexes, by NMR spectroscopy ( 1H, 13C and, for Cd(II), 113Cd).