Tris silane with ammonia

Reaction of Cl3SiC6H2-2,4,6-Ph3 with ammonia affords the tris(amino)-silane compound (H2N)3SiC6H2-2,4,6-Ph3 in 71% yield [Eq. 9]." The X-ray crystal structure was the first for a species in which three NH2 groups were bound to one silicon atom. There is pyramidal geometry at the nitrogen atoms. The structural characterization of a series of such Si-NH2 compounds led to the conclusion that N — Si p-d 77-overlap was not significant in the Si-N bonding.99... 

JL olysilazanes have now been prepared by the catalyzed transamination of HSi[N(CH3)2]3 [tris(dimethylamino)silane, Tris], or its derivatives, with ammonia, primary amines, hydrazines, or diamines. Chlorosilane intermediates are not required in this process, because Tris is readily prepared in excellent yield via a new direct reaction of silicon with dimethylamine. 

Thus, mixtures of different metal alkylamides with comparable ( ) velocities of ammonolysis are reacted with ammonia to form polymetaUasilazanes. Using this approach, for instance, polyborosUazanes of any Si/B-ratio can be obtained via co-ammonolysis of definite amounts of tetrakis(methylamino) silane and tris(dimethylamino)borane [51-53]. 

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