water; dihydrogen peroxide in water addn. of 5 equiv. 30percent H2O2 to suspn. of Pt-complex (free of platinum black), heating to 70°C for 2 h (water-bath); standing overnight (room temp.), cooling in ice, collection (filtration), washing (water, EtOH, ether), drying (vac.); elem. anal.;

in water refluxing for 2 h; pptn. on cooling in ice, collection (filtration), washing (water, Me2CO), drying in air; elem. anal.;