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 RPCl2 1a–i [R = iPr: a; (Me3Si)2CH: b; R=1‐adamantly: c: R=tBu: d; R=Et2N: e; R=iPr2M: f] furnish bis(trichlorosilyl)‐phosphanes RP(SiCl3)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. 1H‐, 31P‐ and 29Si‐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.