Catalysis by rhodium complexes

One of the most confusing problems in the hydrosilylation catalysis by rhodium complexes is the influence of molecular oxygen as a cocatalyst. This is a general phenomenon and also occurs in the presence of other transition metal complexes, such as platinum and ruthenium, particularly those with CO and phosphine ligands. The concerted mechanism of hydrosilylation processes catalyzed by Wilkinson catalyst involves predissociation of the phosphine from the complex. In this respect, molecular oxygen functions as a promoter since the dissociation of phosphine occurs more readily from [RhCl(02)(PPh3)3] than from the... 

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