Radiochromatographic, conductometric and high-frequency titration studies on the thiourea complexes of palladium(II) and platinum(II)

Abstract

Palladium(II) and platinum(II) complexes of thiourea, MTuX 2, MTu 2X 2, MTu 4X 2 (X = Cl,Br,I) and MTu 4A 2 (A = ClO 4,BF 4,CF 3COO), were prepared. Palladium(II) iodide gives a Pd 3Tu 3I 4Cl 2 complex. The complexes PdTuX 2, PdTu 2X 2, PdTu 4X 2 (X = Cl,Br), PdTuA 2, PdTu 2A 2, PdTu 4A 2 (A = ClO 4, BF 4, CF 3COO), PdTu 3(BF 4) 2 and PtTuX 2, PtTu 2X 2, PtTu 4X 2 (X = Cl,Br,I) were identified by high-frequency titration in aqueous solution. Molar conductivities showed that MTuX 2 and MTu 2X 2 are non-electrolytes. In methanol, MTu 4A 2 (A = ClO 4,BF 4, CF 3COO) and PtTu 4X 2 (X = Cl,Br,I) complexes behave as uni-bivalent electrolytes, while PdTu 4X 2 (X = Cl,Br,I) complexes show a reduced conductivity. The conductivities of the halide and trifluoroacetate complexes are even lower in dimethylformamide and show a partial interaction of the anion with the complex. The elution of the complexes with ketones containing an aqueous solution of the sodium salt and with alcohols containing an aqueous solution of the free acid show that in both cases the only species which migrates in compact spots is the very stable (MTu 4] 2+ ion, with very high R F values in the ketone mixture and very low values in the alcohol mixtures.