Reactions and properties of some trimethyleneplatinum(IV) complexes: XI. Fission of the C3 moiety in reactions of platinacyclobutanes

The reactions of the platinacyclobutanes [X2PtCH2CHRCH2(1,10-phenanthroline)] (X  Cl, Br; R  H, CH3) with unsaturated compounds in methyl cyanide, dimethylformamide and dimethylsulphoxide at room temperature have been investigated. Tetracyanoethylene, and styrene and related olefins, promoted the fission of the C3 moiety giving ethylene (R  H) and both ethylene and propene (R  CH3). It is suggested that this gives support to the view that ionization of a halide occurs in these solvents of relatively high dielectric constant and that the five-coordinate positively charged platinacyclobutane species is in equilibrium with a platinum-carbene-olefin complex.