Synthesis, structural characteristics and biological activities of complexes of Zn-II, Cd-II, Hg-II, Pd-II, and Pt-II with 2-acetylpyridine 4-methylthiosermcarbazone

Reaction of 2-acetylpyridine 4-methylthiosemicarbazone (H4ML) with halides of zinc(II), cadmium(II), and mercury(II) afforded complexes of the form [M (H4ML)X-2] [M = Zn-II (1-3), Cd-II (4-6) or Hg-II (7-9); X = Cl, Br, or I]. Reaction of H4ML with K2PdCl4 and K2PtCl4 gave compounds of the form [M(4M L)Cl] [M = Pd-II (10) or Pt-II (11)]. In all the new compounds, which were characterized by elemental analyses, conductance measurements, and electron ic, IR and H-1- and C-13-NMR spectroscopy, and by Cd-113-, Pt-195-, or Hg-1 99-NMR spectroscopy when relevant, the Ligand is N,N,S-tridentate, coordina ting to the metal centre through its pyridine and azomethine nitrogen atoms and its thiocarbonyl sulfur atom, as was confirmed by X-ray diffraction st udies in the cases of 4.2 DMSO, 5.2 DMSO, 6.2 DMSO, 7.2 DMSO, 10, and 11. I n in-vitro assays, only [Zn(H4ML)Cl-2] and [Zn(H4ML)Br-2] showed some sign of antifungal activity against Aspergillus niger or Paecilomyces variotii.