Formation of the platinum-olefin bond catalyzed by SnCl3-

Ethylene exchange in PtCl(C5H7O2)(π-C2H4)

“…Thus the systems studied by Cramer (3) have been discussed in terms of such an intermediate. It has also been used to provide an explanation of the catalytic effects of allyltriethylarsonium cation and trichlorostannate(I1) anion (13,14) in the formation of platinumolefin complexes. In the present case the entropy of activation suggests a highly ordered activated complex, which is not consistent with dissociation of a platinum-oxygen bond.…”

“…and isotopic labelling techniques (14). In many cases rapid exchange is reported, such that the proton resonance spectrum is effectively averaged and only lower limits to the exchange rate can be determined.…”

Transition metal-tin chemistry

“…Early interest in the use of tin(II) halides as cocatalysts was sparked by the discovery that solutions of chloroplatinic acid and stannous chloride quantitatively reduced ethylene and acetylene at room temperature and atmospheric pressure of hydrogen. 28,343,383,384 Tin:platinum ratios of at least 5:1, which were necessary for maximum rates, were shown to form 318,383,386 The high trans effect of the [SnCl3]~ligand is thought to be responsible for both of these results. Simple platinum salts under catalytic conditions frequently deposit colloidal metal.343 Tin(II) chloride prevents this reduction of platinum(II) to platinum metal presumably due to its high ^-acceptor ability, which removes electron density from platinum.…”