Some Platinum IV Compounds

Platinum(IV) has six valency electrons, and a regular octahedral configuration is to be expected in its compounds, as is indeed found to be the case 257). The need for six ligands while the oxidation state is only four leads to some very unusual structures. 

The complex (CII ePt emF (en = ethylencdiamine) contains the centro-symmetric cation [en(CH3)3Pt-en-Pt(CfI,-,)3en]2+, in which there is only one ethylencdiamine bridge methyl groups are arranged in cfs-posi-tions, and the platinum atoms are 7.79 A apart 249). 

In the related compound a-a -dipyridyl-acetylacetonato trimethyl platinum, which is monomeric, five of the coordination positions are taken up by the dipyridyl nitrogen atoms and the methyl groups. The sixth position is occupied by the central carbon atom of the acetylacetone, not by one of the oxygen atoms 242a). The oxygen atoms then remain uncoordinated, and the rest of the acetylacetone group is considerably distorted from the highly symmetrical form it normally has in complexes. This is the only 

This bonding to carbon atoms is again found in cyclopropane platinous chloride, which has recently been shown to contain a four-membered ring of three saturated carbon atoms and a platinum atom (la). The insolubility in noncoordinating media suggests that it is a polymer held together by 

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