Hexamethyldisilane

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Hexamethyldisilane
Hexamethyldisilane.svg
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Names
Preferred IUPAC name
Hexamethyldisilane
Identifiers
3D model (JSmol)
1633463
ChemSpider
ECHA InfoCard 100.014.465 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 215-911-0
PubChem CID
RTECS number
  • JM9170000
UNII
UN number 1993
  • InChI=1S/C6H18Si2/c1-7(2,3)8(4,5)6/h1-6H3 Yes check.svgY
    Key: NEXSMEBSBIABKL-UHFFFAOYSA-N Yes check.svgY
  • C[Si](C)(C)[Si](C)(C)C
Properties
Si2C6H18
Molar mass 146.39 g mol1
AppearanceColourless liquid
Density 0.715 g/cm3
Melting point 14 °C; 57 °F; 287 K
Boiling point 113 °C; 235 °F; 386 K
1.422
Thermochemistry
Std molar
entropy
(S298)
255.89 J K−1 mol−1 (at 22.52 °C)
Hazards
GHS labelling:
GHS-pictogram-flamme.svg GHS-pictogram-exclam.svg GHS-pictogram-silhouette.svg
Danger
H225, H319, H334, H335
P210, P261, P305+P351+P338, P342+P311
Flash point 11 °C (52 °F; 284 K)
Related compounds
Related alkylsilanes
Tetramethylsilane

Triethylsilane

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Hexamethyldisilane (TMS 2) is the organosilicon compound with the formula Si2(CH3)6, abbreviated Si2Me6. It is a colourless liquid, soluble in organic solvents. [1]

Synthesis and reactions

Hexamethyldisilane can be produced by Wurtz-like coupling of trimethylsilyl chloride in the presence of a reducing agent such as potassium graphite:

2 Me3SiCl + 2 K → Me3Si−SiMe3 + 2 KCl

With an excess of the reductant, the alkali metal silyl derivative is produced: [2]

Me3Si−SiMe3 + 2 K → 2 Me3SiK

The Si-Si bond in hexamethyldisilane is cleaved by strong nucleophiles and electrophiles. Alkyl lithium compounds react as follows:

Si2Me6 + RLi → RSiMe3 + LiSiMe3

Iodine gives trimethylsilyl iodide. [3]

Me3SiSiMe3 + I2 → 2 SiMe3I

Related Research Articles

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<span class="mw-page-title-main">Tetrahedrane</span> Hypothetical organic molecule with a tetrahedral structure

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<span class="mw-page-title-main">Trimethylsilyl</span>

A trimethylsilyl group (abbreviated TMS) is a functional group in organic chemistry. This group consists of three methyl groups bonded to a silicon atom [−Si(CH3)3], which is in turn bonded to the rest of a molecule. This structural group is characterized by chemical inertness and a large molecular volume, which makes it useful in a number of applications.

<span class="mw-page-title-main">Sodium bis(trimethylsilyl)amide</span> Chemical compound

Sodium bis(trimethylsilyl)amide is the organosilicon compound with the formula NaN(Si 3)2. This species, usually called NaHMDS, is a strong base used for deprotonation reactions or base-catalyzed reactions. Its advantages are that it is commercially available as a solid and it is soluble not only in ethers, such as THF or diethyl ether, but also in aromatic solvents, like benzene and toluene by virtue of the lipophilic TMS groups.

<span class="mw-page-title-main">Trimethylsilyl chloride</span> Chemical compound

Trimethylsilyl chloride, also known as chlorotrimethylsilane is an organosilicon compound (silyl halide), with the formula (CH3)3SiCl, often abbreviated Me3SiCl or TMSCl. It is a colourless volatile liquid that is stable in the absence of water. It is widely used in organic chemistry.

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<span class="mw-page-title-main">Bis(trimethylsilyl)mercury</span> Chemical compound

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Bis(trimethylsilyl)amine (also known as hexamethyldisilazane and HMDS) is an organosilicon compound with the molecular formula [(CH3)3Si]2NH. The molecule is a derivative of ammonia with trimethylsilyl groups in place of two hydrogen atoms. An electron diffraction study shows that silicon-nitrogen bond length (173.5 pm) and Si-N-Si bond angle (125.5°) to be similar to disilazane (in which methyl groups are replaced by hydrogen atoms) suggesting that steric factors are not a factor in regulating angles in this case. This colorless liquid is a reagent and a precursor to bases that are popular in organic synthesis and organometallic chemistry. Additionally, HMDS is also increasingly used as molecular precursor in chemical vapor deposition techniques to deposit silicon carbonitride thin films or coatings.

<span class="mw-page-title-main">Hexamethyldisiloxane</span> Chemical compound

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<span class="mw-page-title-main">Lithium bis(trimethylsilyl)amide</span> Chemical compound

Lithium bis(trimethylsilyl)amide is a lithiated organosilicon compound with the formula LiN(Si 3)2. It is commonly abbreviated as LiHMDS or Li(HMDS) and is primarily used as a strong non-nucleophilic base and as a ligand. Like many lithium reagents, it has a tendency to aggregate and will form a cyclic trimer in the absence of coordinating species.

The perrhenate ion is the anion with the formula ReO
4
, or a compound containing this ion. The perrhenate anion is tetrahedral, being similar in size and shape to perchlorate and the valence isoelectronic permanganate. The perrhenate anion is stable over a broad pH range and can be precipitated from solutions with the use of organic cations. At normal pH, perrhenate exists as metaperrhenate, but at high pH mesoperrhenate forms. Perrhenate, like its conjugate acid perrhenic acid, features rhenium in the oxidation state of +7 with a d0 configuration. Solid perrhenate salts takes on the color of the cation.

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Metal bis(trimethylsilyl)amides are coordination complexes composed of a cationic metal with anionic bis(trimethylsilyl)amide ligands and are part of a broader category of metal amides.

<span class="mw-page-title-main">Trimethylsilyl iodide</span> Chemical compound

Trimethylsilyl iodide (iodotrimethylsilane or TMSI) is an organosilicon compound with the chemical formula (CH3)3SiI. It is a colorless, volatile liquid at room temperature.

<span class="mw-page-title-main">Trimethylsilyl cyclopentadiene</span> Chemical compound

Trimethylsilyl cyclopentadiene is an organosilicon compound with the chemical formula C5H5Si(CH3)3. It exists as a colorless liquid. It is used in the synthesis of some metal cyclopentadienyl complexes and has attracted interest for its fluxional structure.

<span class="mw-page-title-main">Tris(trimethylsilyl)phosphine</span> Chemical compound

Tris(trimethylsilyl)phosphine is the organophosphorus compound with the formula P(SiMe3)3 (Me = methyl). It is a colorless liquid that ignites in air and hydrolyses readily.

<span class="mw-page-title-main">Tris(trimethylsilyl)silane</span> Chemical compound

Tris(trimethylsilyl)silane is the organosilicon compound with the formula (Me3Si)3SiH (where Me = CH3). It is a colorless liquid that is classified as a hydrosilane since it contains an Si-H bond. The compound is notable as having a weak Si-H bond, with a bond dissociation energy estimated at 84 kcal/mol. For comparison, the Si-H bond in trimethylsilane is 94 kcal/mol. With such a weak bond, the compound is used as a reagent to deliver hydrogen atoms. The compound has been described as an environmentally benign analogue of tributyltin hydride.

In chemistry, transition metal silyl complexes describe coordination complexes in which a transition metal is bonded to an anionic silyl ligand, forming a metal-silicon sigma bond. This class of complexes are numerous and some are technologically significant as intermediates in hydrosilylation. These complexes are a subset of organosilicon compounds.

References

  1. Tamejiro Hiyama, Manabu Kuroboshi, "Hexamethyldisilane" Encyclopedia of Reagents for Organic Synthesis, 2001 John Wiley & Sons. doi : 10.1002/047084289X.rh015
  2. Fürstner, Alois; Weidmann, Hans (1988). "Efficient formation and cleavage of disilanes by potassium-graphite. Silylation with silyl metal reagents". Journal of Organometallic Chemistry. 354: 15–21. doi:10.1016/0022-328X(88)80634-X.
  3. Olah, G.; Narang, S.C. (1982). "Iodotrimethylsilane—a versatile synthetic reagent". Tetrahedron . 38 (15): 2225. doi:10.1016/0040-4020(82)87002-6.