THERMAL-ANALYSIS OF COORDINATION-COMPOUNDS .3. THERMAL-DECOMPOSITION OF PLATINUM COMPLEXES CONTAINING TRIPHENYLPHOSPHINE, TRIPHENYLARSINE AND TRIPHENYLSTIBINE

Studies by thermogravimetric analysis (TG) and differential thermal an alysis (DTA) of the complexes [PtCl(2)L(2)] (L is PPh(3), AsPh(3), SbP h(3)), [PtL(n)] (n = 3, L is SbPh(3); n = 4, L is PPh(3), AsPh(3)); [( PtL(3))(2)N-2]; [(PtL(3))(2)C-2] and [Pt(CO)(2)L(2)] (L is SbPh(3)) ar e described. Analysis of the TG and DTA curves showed that Pt(II) comp lexes of the type [PtCl(2)L(2)] have a higher thermal stability than t he corresponding Pt(0) complexes of the type [PtL(n)], with the except ion of [Pt(SbPh(3))(3)], which is more stable than [PtCl2(SbPh(3))(2)] . Thermal stabilities of each of the complexes are compared with those of the others in the series. Mechanisms of thermal decomposition of c omplexes of the types [PtCl(2)L(2)] and [PtL(n)] are proposed. Residue s of the samples were characterized by chemical tests and IR spectrosc opy. The residue from the thermal decomposition of [PtCl(2)L(2)] (L is PPh(3), AsPh(3)) and [Pt(PPh(3))(4)] is metallic platinum. For [Pt(As Ph(3))(4)] the residue is a mixture of Pt and As, whereas for the comp lexes containing SbPh, the residues are mixtures of Pt and Sb. In thes e cases, the proportional contents of Pt and As or Pt and Sb correspon d to the stoichiometry of these elements in the respective complexes. The complexes {[Pt(SbPh(3))(3)]N-2(2)}, {[Pt(SbPh(3))(3)]C-2(2)} lose N-2 or the ethynediyl group at 130-150 degrees C and are transformed i nto [Pt(SbPh(3))(3)].