Chloro-olefine Complexes of Platinum

ALTHOUGH the reactions of fluoro-olefines with transition metal complexes have yielded very stable fluoro-olefine and fluorocarbon complexes 1–3 analogous reactions with chloro-olefines have hitherto resulted in chlorination to form metal chlorine bonds 4–6 . We find, however, that on refluxing a benzene solution of Pt(PPh 3 ) 4 (ref. 7) with tetrachloroethylene the complex (Ph 3 P) 2 PtC 2 Cl 4 is formed in high yield as white air stable crystals with a melting point of 278° C dec. This would seem to be the first example of a perchloro-olefine transition metal complex. The reaction of Pt(PPh 3 ) 4 with a number of halogeno-olefines, for example, tetrafluoroethylene, trichloroethy-lene, trans -dichloroethylene, 1,1,1-trifluoro-2,3,3-trichloro-2-propene, appears to be a general reaction for the preparation of complexes of the type (Ph 3 P) 2 Pt olefine. The complexes prepared in this work and the recently described tetracyanoethylene 8 complex are considerably more stable than the olefine complexes of this type which were originally prepared with trans -stilbene, trans 4,4, dinitrostilbene and acenaphthylene 9 .