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Zinc, Cadmium and Mercury Dithiocarboxylates: Synthesis, Characterization, Structure and Their Transformation to Metal Sulfide Nanoparticles

2007; Wiley; Volume: 2007; Issue: 11 Linguagem: Inglês

10.1002/ejic.200601059

1099-0682

G. Kedarnath, Vimal K. Jain, Shamik Ghoshal, G.K. Dey, C.A. Ellis, Edward R. T. Tiekink,

Chalcogenide Semiconductor Thin Films

Abstract Reactions of M(OAc) 2 · n H 2 O and M(OAc) 2 (tmeda) with dithiocarboxylic acids gave [M(S 2 CTol) 2 ] n ( 1 ) (M = Zn or Cd; Tol = C 6 H 4 Me‐4) and [M(S 2 CAr) 2 (tmeda)] ( 3 ) (M = Zn, Cd, Hg; Ar = Ph or Tol), respectively, in high yields as deep‐colored crystalline solids. The former are soluble in pyridine to give pyridine adducts [M(S 2 CTol) 2 (py)] ( 2 ). These complexes were characterized by elemental analysis, UV/Vis and NMR ( 1 H, 13 C) spectroscopy. The absorptions in the electronic spectra have been assigned to ligand‐to‐ligand charge‐transfer transitions. The crystal and molecular structures of the monomeric species [Zn(S 2 CTol) 2 (py)] ( 2 ), [Zn(S 2 CPh) 2 (tmeda)] ( 3a ), [Zn(S 2 CTol) 2 (tmeda)] ( 3b ) and [Cd(S 2 CTol) 2 (tmeda)] ( 3d ) have been established by X‐ray crystallography. In [Zn(S 2 CTol) 2 (py)], chelating dithiocarboxylate ligands and pyridine define a coordination geometry intermediate between square pyramidal and trigonal bipyramidal. In each of 3a and 3b , tetrahedral N 2 S 2 coordination geometries are found as the dithiocarboxylate ligands are effectively monodentate; evidence for the greater coordination potential is found for – S 2 CTol over – S 2 CPh. Chelating dithiocarboxylate ligands in [Cd(S 2 CTol) 2 (tmeda)] ( 3d ) lead to an octahedral geometry. Thermal behavior has been studied by thermogravimetric analysis. The [M(S 2 CAr) 2 (tmeda)] complexes underwent a three‐step decomposition. Pyrolysis in the temperature range 300–500 °C and solvothermal decomposition in ethylenediamine and hexadecylamine (HDA) gave metal sulfide nanoparticles. The MS (M = Zn, Cd, Hg) nanoparticles were characterized by XRD, EDAX, absorption/emission spectroscopy and electron microscopy (TEM). Solvothermal decomposition gave hexagonal phases of nanoparticles whereas heating in a furnace gave cubic ZnS and HgS, and hexagonal CdS. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)