Preparation of intermetallic phases of noble metals and tin by thermolysis of metal-organic coordination polymers

Intermetallic phases of noble metals (Ru, Rh, Pd, Os, Ir, Pt and Au) were prepared by controlled thermolysis of coordination polymers on the basis of cyanometallates and trimethyltin units (super-prussian blue derivatives). The thermal reaction was carried out under different atmospheres: oxidizing, inert and reducing, upto 1000 °C. Under oxidizing conditions, intimate mixtures of oxides (SnO2 with RuO2, Rh2O3, IrO2, Pt3O4, respectively) were obtained that could be reduced in a second step to the pure noble metals and intermetallic phases incorporating tin (Ru3Sn7, RhSn2, IrSn4, Ir5Sn7, IrSn2, PdSn2, Pd20Sn13, Pd3Sn2, PtSn, PtSn4, Au5Sn, AuSn were all detected). Under reducing conditions, mixtures of metals and intermetallic phases were obtained that could subsequently be oxidized by further thermal treatment to noble metals on SnO2. This offers a new synthetic pathway to such intermetallics and to noble metals on SnO2 supports.