Tris(triisopropylsilyl)silane (iPr
3Si)
3SiH has been synthesized and studied by X-ray andneutron diffraction. It possesses an unusual structure in which the four silicon atoms arenearly coplanar,
![](/images/entities/ang.gif)
Si-Si-Si = 118.41(5)
![](/images/entities/deg.gif)
. The Si-H distance is found to have a normalvalue of 1.506(2) Å. Thermal and room-temperature photochemical decomposition of (iPr
3Si)
3SiH leads to the elimination of iPr
3SiH and the generation of bis(triisopropylsilyl)silylene,[(iPr
3Si)
2Si:]. Reactions of (iPr
3Si)
2Si: include precedented insertions into H-Si bonds andaddition to the
![](/images/gifchars/pi.gif)
-bonds of olefins, alkynes, and dienes. Despite theoretical predictions of atriplet ground state for [(iPr
3Si)
2Si:], stereospecific addition to
cis- and
trans-2-butene wasobserved.