Platinum complexes binuclear hydrides

A number of dppm complexes with hydride and methylene bridges have been referenced already in this chapter under the respective sections on hydrides and carbenes. These compounds will not be included again here. The binuclear platinum(I) chemistry of these complexes has also been developed. The complexes have a metal-metal bond between platinums, although this may be broken by formation of A-frame type molecules. This chemistry has been described in a series of papers, and the reaction types are outlined in Schemes 13 and 14, i28 .1438-1445 a similar chemistry will likely develop with the methylated ligand Me2PCH2PMe2.1450... 

Attempts have been made to mimic proposed steps in catalysis at a platinum metal surface using well-characterized binuclear platinum complexes. A series of such complexes, stabilized by bridging bis(diphenyl-phosphino)methane ligands, has been prepared and structurally characterized. Included are diplati-num(I) complexes with Pt-Pt bonds, complexes with bridging hydride, carbonyl or methylene groups, and binuclear methylplatinum complexes. Reactions of these complexes have been studied and new binuclear oxidative addition and reductive elimination reactions, and a new catalyst for the water gas shift reaction have been discovered. 

The great majority of platinum(I) complexes are binuclear with monofunctional or bifunctional bridging groups. However, there is also a series of unsupported dimers with the general structure shown in (12). These are generally stabilized by phosphine, carbonyl, and isocyanide ligands.17 Dimeric hydride complexes can have terminal or bridging hydrides and these are discussed above in Section 6.5.2.1.4. 

---