Convenient high-pressure syntheses of [PtX3(C2H4)]− (X = Cl, Br) salts with a variety of organic cations from PtX2

Reaction between PtX2 (X = Cl or Br) with an equimolar amount of the appropriate [Cat]+X− in toluene in an autoclave under 25 bars of C2H4 yields the corresponding [Cat][PtX3(C2H4)] in moderate to excellent isolated yields and high purity (X = Cl, Cat = nBu4P; X = Br, Cat = nBu4P, Ph4P, nBu4N). The same reaction does not yield any olefin complex if X = I and no reaction also occurs for the PtBr2 + KBr system in water, THF, acetone or toluene.