The production of class-II mixed-valence complexes in the redox reaction between dithiomalonamide and platinum(IV) or palladium(IV)
Due to its joint reducing and complexing properties, dithiomalonamide (HL) reacts with [PtX6]2– and [PdX6]2– ions to afford two types of complexes which, on the basis of microanalytical data, may be formulated as M(HL)X3 and M(HL)2X3 respectively. A detailed investigation of their behaviour in solution (1H, 13C, and 195Pt n.m.r.) and in the solid state (i.r., visible, x.p.s., and electrical conductivity measurements) has been performed. The experimental data show the two types of complexes to be mixed-valence compounds which are best formulated as [MII(HL)2][MIVX6] and [MII(HL)2][MIV(HL)2X2]X4 respectively. In these complexes, dithiomalonamide co-ordinates to palladium and platinum either via SN or S2 donation. They are recognised as semiconductors with electrical conductivities up to –10–4Ω–1 cm–1.