Reactions of Silicon–Silicon Bonds, VI . Reductive Trichloroslilylation Reactions Leading to Alkyl‐ and Dialkylaminobis(trichlorosilyl)phosphanes

Reactions of hexachlorodisilane and of trichlorosilane/triethylamine with alkyl‐and dialkylaminodichlorophosphanes RPCl 2 1a – i [R = i Pr: a ; (Me 3 Si) 2 CH: b ; R=1‐adamantly: c : R= t Bu: d ; R=Et 2 N: e ; R= i Pr 2 M: f ] furnish bis(trichlorosilyl)‐phosphanes RP(SiCl 3 ) 2 3a –f. However, when less bulky substituents are attached to the phosphorus atom, so that there is little steric crowding, the double reductive silylations leading from 1 to 3 are accompanied by side reactions and decomposition of 3 . Therefore, only 3b , 3c , 3d , and 3f wre isolated in a pure state. These compounds are more readily prepared by the; trichlorosilane/triethylamine method. 1 H‐, 31 P‐ and 29 Si‐Nmr spectra confirm their constitution. The structure of solid 3f , the first aminobis(trichlorosilyl)phosphane, was determined by X‐ray crystallography. 3f contains a phosphorus atom in a pyramidal environment surrounded by two silicon atoms and a planar nitrogen atom of the diisopropylamino group.