The Tris(pentafluoroethyl)silanide Anion

Abstract

Tris(pentafluoroethyl)silane, which is conveniently accessible by the treatment of Si(C₂ F₅ )₃ X (X=Cl, Br) with Bu₃ SnH, was successfully employed for hydrosilylation reactions. In the presence of a palladium catalyst, hydrosilylation of phenylacetylene with Si(C₂ F₅ )₃ H affords the product of an α-addition whereas the reaction of trimethylsilylacetylene with the silane leads to the β-trans product. Tris(pentafluoroethyl)silane can be deprotonated by sterically demanding bases such as lithium diisopropylamide at low temperatures to give the corresponding silanide ion. The addition of crown ethers or cryptands to this highly reactive species enabled the isolation and characterization of salt-like tris(pentafluoroethyl)silanide at room temperature.

Keywords: fluorine; hydrosilylation; perfluoroalkyl compounds; silanes; silanides.