The preparation and properties of dimethylamino- and diethylaminosilane

Abstract

Dimethylaminosilane and diethylaminosilane have been prepared almost quantitatively from the reactions of iodosilane with dimethylamine and diethylamine. Physical properties, including infrared and mass spectra, are reported and discussed, and a new value for the heat of association of solid SiH₃NMe₂ is presented. Pyrolysis of these aminosilanes leads mainly to disproportionation about silicon. Both compounds behave as weak Lewis bases. With hydrogen chloride, the initial products at –96° are SiH₃NMe₂,2HCl and SiH₃NEt₂,3HCl; these adducts (which may be ionic in nature) decompose at higher temperatures to give chlorosilane and dialkylammonium chloride. With trimethylborane and SiH₃NEt₂, a weak 1 : 1 adduct is formed, whilst iodosilane affords the more robust adducts SiH₃NR₂,SiH₃l (R = Me, Et).