Tris(triisopropylsilyl)silane and the generation of bis (triisopropylsilyl)silylene

Tris(triisopropylsilyl)silane (iPr(3)Si)(3)SiH has been synthesized and stu died by X-ray and neutron diffraction. It possesses an unusual structure in which the four silicon atoms are nearly coplanar, angle Si-Si-Si = 118.41( 5)degrees. The Si-H distance is found to have a normal value of 1.506(2) An gstrom. Thermal and room-temperature photochemical decomposition of (iPr(3) -Si)(3)SiH leads to the elimination of iPr(3)SiH and the generation of bis( triisopropylsilyl)silylene, [(iPr(3)Si)(2)Si:]. Reactions of(iPr(3)Si)(2)Si : include precedented insertions into H-Si bonds and addition to the pi-bon ds of olefins, alkynes, and dienes. Despite theoretical predictions of a tr iplet ground state for [(iPr(3)Si)(2)Si:], stereospecific addition to cis- and trans-2-butene was observed.