Hydrolytic reactions, organosilanes

Although organosilanes appear to react slowly (if at all) with water alone, in the presence of acids or bases (e.g., alkali metal hydroxides), reactions to give a silanol and H2 are rapid, with bases being particularly powerful catalysts. The evolution of H2 in this type of reaction may be used as both a qualitative and a quantitative test for Si-H bonds, and the mechanism of the acid and the base hydrolysis has been discussed in detail (30,31). This hydrolytic method is not very common for the preparation of silanols that are to be isolated, because both acids and bases catalyze the condensation of silanols to siloxanes, and therefore, only compounds containing large substituents are conveniently made in this way. If an anhydrous alkali metal salt is used, a metal siloxide may be isolated and subsequently hydrolyzed to give the silanol [Eq. (10)] (32). 

Organosilanes bearing a phosphine imide moiety have been synthesized from phosphine imide in ethyl ether and characterized crystallographically. In ether solution, a dynamic equilibrium exists between the chelated pentacoordinated and unchelated tetra-coordinated silicon moieties. Reaction of the pentacoordinated derivative with water gives [2-(diphenylphosphino)phenyl]diphenylsilanol accompanied by both reduction of the phosphine imide moiety and the hydrolytic oxidation of the Si-H moiety." °... 

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