Tris(trimethylsilyl)phosphine is the
organophosphorus compound
Organophosphorus compounds are organic compounds containing phosphorus. They are used primarily in pest control as an alternative to chlorinated hydrocarbons that persist in the environment. Some organophosphorus compounds are highly effective in ...
with the formula P(SiMe
3)
3 (Me =
methyl
In organic chemistry, a methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms, having chemical formula . In formulas, the group is often abbreviated as Me. This hydrocarbon group occurs in many ...
). It is a colorless liquid that ignites in air and hydrolyses readily.
Synthesis
Tris(trimethylsilyl)phosphine is prepared by treating trimethylsilyl chloride,
white phosphorus
Elemental phosphorus can exist in several allotropes, the most common of which are white and red solids. Solid violet and black allotropes are also known. Gaseous phosphorus exists as diphosphorus and atomic phosphorus.
White phosphorus
White ...
, and sodium-potassium alloy:
:1/4 P
4 + 3 Me
3SiCl + 3 K → P(SiMe
3)
3 + 3 KCl
Several other methods exist.
[
]
Reactions
The compound hydrolyzes to give 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(SiMe3)3 + 3 H2O → PH3 + 3 HOSiMe3
Treatment of certain acyl chloride
In organic chemistry, an acyl chloride (or acid chloride) is an organic compound with the functional group . Their formula is usually written , where R is a side chain. They are reactive derivatives of carboxylic acids (). A specific example o ...
s with tris(trimethylsilyl)phosphine gives phosphaalkyne
In chemistry, a phosphaalkyne (IUPAC name: alkylidynephosphane) is an organophosphorus compound containing a triple bond between phosphorus and carbon with the general formula R-C≡P. Phosphaalkynes are the heavier congeners of nitriles, though, ...
s, one example being tert-butylphosphaacetylene.
:
Reaction with potassium tert-butoxide
Potassium ''tert''-butoxide is the chemical compound with the formula K+(CH3)3CO−. This colourless solid is a strong base (pKa of conjugate acid around 17), which is useful in organic synthesis. It exists as a tetrameric cubane-type cluster ...
cleaves one P-Si bond, giving the phosphide
In chemistry, a phosphide is a compound containing the ion or its equivalent. Many different phosphides are known, with widely differing structures. Most commonly encountered on the binary phosphides, i.e. those materials consisting only of phos ...
salt:[{{cite book, chapter=Phosphaalkynes
, author1=Russell, Christopher A. , author2=Townsend, Nell S., editor1=Kamer, Paul C. J. , editor2=Van Leeuwen, Piet W. N. M
, title=Phosphorus(III) Ligands in Homogeneous Catalysis, year=2012, pages=343–354, publisher=Wiley-VCH, doi=10.1002/9781118299715.ch11, isbn=9781118299715]
:P(SiMe3)3 + KO-t-Bu → KP(SiMe3)2 + Me3SiO-t-Bu
It is a reagent in the preparation of metal phosphido clusters by reaction with metal halides or carboxylates. In such reactions the silyl halide or silyl carboxylate is liberated as illustrated in this idealized reaction:
:P(SiMe3)3 + 3 CuCl → Cu3P + 3 ClSiMe3
Safety
Tris(trimethylsilyl)phosphine spontaneously ignites in air, thus it is handled using air-free technique Air-free techniques refer to a range of manipulations in the chemistry laboratory for the handling of compounds that are air-sensitive. These techniques prevent the compounds from reacting with components of air, usually water and oxygen; less comm ...
s.
References
Trimethylsilyl compounds
Phosphines