1. Field of the Invention
This invention relates to reaction of beta platinum chloride with gaseous ammonia to yield metallic platinum or useful addition complexes characterized by the formula PtCl.sub.2 .multidot. X NH.sub.3 where X is greater than zero up to about 2.
2. Description of the Prior Art
It has been reported by W. Peters In Z. Anorg. Chem. 77 (1912) p. 137 et seq. that PtCl.sub.2, prepared from thermally decomposing chloroplatininc acid, reacts with gaseous ammonia to produce a compound PtCl.sub.2 .multidot. 5NH.sub.3. In carrying out such reaction, Peters exposed anhydrous PtCl.sub.2 to ammonia very slowly and maintained the solid at approximately room temperature by regulating the flow of ammonia. The material prepared by Peters is distinct from the compounds described herein. Insofar as is known, the reduction of beta platinum chloride with gaseous ammonia to yield metallic platinum, which offers a convenient method for synthesis of supported platinum metal catalysts, has not been reported.
Crystalline platinum compounds having the empirical formulae Pt(NH.sub.3)Cl.sub.2 and cis and trans Pt(NH.sub.3).sub.2 Cl.sub.2 have been respectively reported by Kerr et al. Inorg. Chem., 13 2294 (1974) and Watt et al. Journal of Electrochem. Soc. 110, 716 (1963). The compounds described herein formed by the direct reaction of beta platinum chloride and ammonia gas characterized by the same empirical formulas but different crystalline structure or the absence of crystallinity, e.g., amorphous solids, have not been reported.