4-methylpyridinium salts of planar nickel(II), palladium(II) and platinum(II) 1,2-dithiooxalato-S,S′ complexes. Preparation chemical characterization and thermal behaviour

Abstract

Three salts of planar inorganic dithiooxalato complexes, (HB) 2[Ni(dto) 2] ( 1), (HB) 2[Pd(dto) 2] ( 2) and (HB) 2[Pt(dto) 2] ( 3), where HB + is 4-methylpyridinium and dto 2− is the 1,2-dithiooxalato- S,S′ ligand, were synthesized and characterized by elemental analysis, IR and UV-vis spectroscopies, thermal analysis (TG, DTG and DTA) and X-ray diffraction techniques. The IR and UV-vis spectra support the presence of the aromatic cation and the complex anions. The three compounds are isostructural and crystallize in the monoclinic space group P2 1/ n. 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. In an argon-oxygen atmosphere, the final residues were a mixture of nickel sulphides, oxides and sulphate for 1, metallic palladium and palladium(II) oxide for 2, and platinum(0) for 3. Thermal decompositions in the inert atmosphere yielded nickel(II) sulphide, a mixture of Pd/PdS and metallic platinum, respectively.