SYNTHESES, CHEMICAL CHARACTERIZATION, AND THERMOCHEMISTRY OF PYRIDINIUM SALTS OF 1,2-DITHIOOXALATO-S,S' COMPLEXES OF NI(II), PD(II) AND PT(II)

Three complexes of formula (HB)(2)[M(dto)(2)] where HB+ is pyridinium, M is Ni(II), Pd(II) or Pt(II), and dto(2-) is 1,2-dithiooxalato-S,S' (hereafter abbreviated as NIDTPY, PDDTPY and PTDTPY, respectively) hav e been synthesized and characterized by elemental analysis, IR and UV- vis spectroscopies and X-ray diffraction techniques. Thermal decomposi tions of compounds have been studied by thermogravimetry (TG and DTG) and differential thermal analysis (DTA) under argon-oxygen and argon a tmospheres. The final decomposition products were identified by elemen tal analysis and the X-ray powder diffraction technique. Thermoanalyti cal data show that the surrounding atmosphere influences the course of the decomposition process, and the final products. In argon-oxygen at mosphere, the final residues were identified as a mixture of nickel su lphides, oxides and sulphate for the nickel compound, Pd(0) and PdO fo r the palladium compound, and platinum(0) for the platinum compound. T hermal decompositions in argon atmosphere yielded nickel(II) sulphide, a mixture of Pd/PdS, and metallic platinum, respectively.