Carbon monoxide unsaturated metal clusters

Many transition metal cluster compounds are metal carbonyl derivatives. Many metal carbonyl derivatives lose carbon monoxide upon pyrolysis or photolysis. If these decomposition processes are controlled, a reactive coordinatively unsaturated metal carbonyl fragment which oligomerizes to a metal carbonyl cluster may be obtained, as exemplified by the following syntheses of metal carbonyl cluster compounds discussed later in this chapter, on pages 399, 396, and 375, respectively. 

Another example of orthometallation is the series of reactions shown in Fig. 2.65. The thermal treatment of the compound Os3(CO)n(PPh2R)(R = Ph or Me) induces loss of carbon monoxide providing cluster unsaturation which promotes in turn the activation of a C-H bond in the phosphine giving finally Os3(CO)9( 3-C6H4)(/i3-PR). The metallation of two carbon atoms observed in... 

Thermal Activation. As often discussed in previous sections, metal clusters, in general, undergo relatively easy thermal decomposition with carbon monoxide ejection. From these reactions highly reactive coordinately unsaturated derivatives which can be active catalysts arise. 

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