Main group element oxides reactions with transition metal complexes

Some attempts which I had made in 1946 to obtain PtPh2 or [PtPhJ from the reaction of phenylmagnesium bromide with [ PtCl2(C2H4)2 2] in ether had yielded biphenyl as the only pure solid product, and this served to confirm in my mind the belief that transition metals had no normal organometallic chemistry. I decided then to concentrate on the platinum(II)-olefin complexes. The first question was whether the olefin-metal bond used the d electrons normally involved in the oxidation of platinum(II) to platinum(IV) (valence d electrons) to bind the olefin, as required by such structures as (I), or whether, as was then generally believed, they were olefin coordination compounds formed independently of the presence of d electrons, even by Main Group element ions. 

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