Silyl hydride group

Both disilazanes A and B, which are readily prepared and isolated, may be cocondensed with other polymeric polysilazanes. By cocondensation, the controlled introduction of either (or both) vinyl and silyl hydride groups can be accomplished readily. In turn, these groups provide a convenient cross-linking mechanism for these polymers via platinum catalysis or thermal inducement of hydrosilation. This method eliminates the need for cross-linking via hydrolysis or oxidation, which introduces undesirable oxygen bonds. Other advantages will be treated in a later section. 

The product is a white resin that is soluble in hexane and can be cross-linked by further condensation or through reactions involving vinyl and silyl hydride groups. 

The strong catalytic effect of amines in silylation with silyl hydrides of some protic substrates, like alcohols, phenols, and carboxylic acids, is well known (for review, see Ref. 316). In this case, the amine is not likely to ionize the silicon-leaving group bond. General base catalysis has been... 

Although it is now almost fifty years since Speier and his colleagues first announced the chloroplatinic acid-catalyzed hydrosilation of olefins, we are still far from complete control of the chemistry. A particular problem is the suppression of double bond migration. A solution of this problem will require a more detailed understanding of the factors affecting the relative rates of P-hydride elimination from an alkyl group and of the reductive elimination of Si-H from a platinum silyl hydride complex. Another factor which is poorly understood is suppression of the irreversible reduction of the platinum catalyst to Pt° metal. Both of these problems can greatly increase costs of production of certain products. 

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