Phenylsilane, also known as silylbenzene, a colorless liquid, is one of the simplest organosilanes with the formula C₆ H₅ SiH₃. It is structurally related to

toluene Toluene (), also known as toluol (), is a substituted aromatic hydrocarbon. It is a colorless, water-insoluble liquid with the smell associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a methyl group (CH3) a ...

, with a silyl group replacing the methyl group. Both of these compounds have similar densities and boiling points due to these similarities. Phenylsilane is soluble in organic solvents.

Synthesis and reactions

Phenylsilane is produced in two steps from Si(OEt)₄. In the first step, phenylmagnesium bromide is added to form Ph−Si(OEt)₃ via a

Grignard reaction The Grignard reaction () is an organometallic chemical reaction in which alkyl, allyl, vinyl, or aryl-magnesium halides (Grignard reagent) is added to a carbonyl group in an aldehyde or ketone. This reaction is important for the formation of ...

. Reduction of the resulting Ph−Si(OEt)₃ product with LiAlH₄ affords phenylsilane. :Ph−MgBr + Si(OEt)₄ → Ph−Si(OEt)₃ + MgBr(OEt) :4 Ph−Si(OEt)₃ + 3 LiAlH₄ → 4 Ph−SiH₃ + 3 LiAl(OEt)₄

Uses

Phenylsilane can be used to reduce tertiary phosphine oxides to the corresponding tertiary

phosphine Phosphine (IUPAC name: phosphane) is a colorless, flammable, highly toxic compound with the chemical formula , classed as a pnictogen hydride. Pure phosphine is odorless, but technical grade samples have a highly unpleasant odor like rotting ...

. :P(CH₃)₃O + PhSiH₃ → P(CH₃)₃ + PhSiH₂OH The use of phenylsilane proceeds with retention of configuration at the phosphine. For example, cyclic chiral tertiary phosphine oxides can be reduced to cyclic tertiary phosphines. Phenylsilane combines with caesium fluoride to give the

ate complex In chemistry, an ate complex is a salt formed by the reaction of a Lewis acid with a Lewis base whereby the central atom (from the Lewis acid) increases its valence and gains a negative formal charge. (In this definition, the meaning of valence i ...

hSiFH₃sup>−. This species functions as a hydride donor, reducing 4-oxazolium salts to 4-

oxazoline Oxazoline is a five-membered heterocyclic organic compound with the formula . It is the parent of a family of compounds called oxazolines (emphasis on plural), which contain non-hydrogenic substituents on carbon and/or nitrogen. Oxazolines are the ...

References

{{reflist Carbosilanes Phenyl compounds