Synthesis, chemical characterization, structural data and thermal behaviour of 3-methylpyridinium salts of 1,2-dithiooxalato-s,s′ complexes with formula (HB) 2[M(S 2C 2O 2) 2] (M = Ni II, Pd II and Pt II)

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Microcrystalline powders of three complexes of formula (HC 6H 7N) 2 [Ni(S 2C 2O 2) 2] ( 1), (HC 6H 7N) 2[Pd(S 2C 2O 2) 2] ( 2) and (HC 6H 7N) 2[Pt(S 2C 2O 2) 2] ( 3), were synthesized and characterized by elemental analysis. IR and UV-vis spectroscopies, thermal analysis (TG, DTG and DTA) and X-ray powder diffraction techniques. The IR and UV-vis spectra support the presence of the aromatic cation and the complex anion. The three compounds are isostructural, and crystallize in the monoclinic space group P2 1/ n with Z = 2. Thermal studies give evidence that the mechanism and the final solid products are strongly influenced by the atmospheric conditions. The final decomposition products were identified by elemental analysis and the X-ray powder diffraction technique. Thermal decomposition in argon-oxygen atmosphere, gave final residues identified as a mixture of nickel sulphides, oxides and sulphate for 1, metallic palladium and palladium(II) oxide for 2, and platinum(O) for 3. Thermal decompositions in the inert atmosphere yielded nickel(II) sulphide, a mixture of Pd/PdS, and metallic platinum, respectively.