Hydroplatinum complexes

XLVII) 16). The mechanism proposed involves the intermediacy of a hydroplatinum complex, which leads to the final product via the elimination of methane (Eq. 61). The reaction between dicyanoacetylene and PtHCl(PEtg)2 or PtHCl(PPh3)a has been studied and the product... 

A reaction that may involve an electrophilic attack is the exchange of hydroplatinum complexes with water. This reaction has been studied for the isotopic exchange reaction of PtHCl(PEt3)2 with DgO, which is very slow in the absence of added acid (149). 

For the hydrogenation of ethylene and acetylene with chloroplatinic acid and stannous chloride as catalyst, a number of steps have been outlined which are characteristic of the mechanism 305). These steps are (1) competitive formation of a rr-ethyleneplatinum and a hydroplatinum complex (2) formation of the hydro-rr-ethyleneplatinum complex (3) rearrangement by insertion to form an ethylplatinum complex and (4) attack of the protonic hydrogen on the metal-carbon bond to form ethane and the catalyst. The reduction of acetylene to ethane proceeds via the intermediate formation of ethylene. 

In 1968, Glockling and Hooton proposed that the oxidative addition of HCl to [Pt(GeMe3)(diphos)(PEt3)]Cl gave the hydroplatinum(IV) complex (XIV) (161) ... 

The reaction is reversible. If a fluorinated olefin is used, it would be expected that the resulting fluoroalkyl compound would be readily obtained, since the greater strength of the metal-fluorocarbon bond as compared to the metal-hydrocarbon bond favors the insertion reaction 267). The reaction of hydroplatinum(II) complexes with fluoroolefins has been extensively studied. A surprising product from a number of these reactions is a fluorovinyl compound rather than the anticipated fluoroalkyl complex. In Fig. 4 are shown the reactions of PtHCl(PEt3)2 with a series of fluoroolefins to give PtCl(CF=CF2)(PEt3)2 (XXXIV)... 

The protonation of zero-valent platinum-acetylene complexes has been discussed by several workers, and a mechanism proposed involving insertion of the acetylene into a hydroplatinum bond 287). The reaction... 

---