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'''Hexamethyldisilane''' (]<sub>2</sub>) is the ] with the formula Si<sub>2</sub>(CH<sub>3</sub>)<sub>6</sub>, abbreviated Si<sub>2</sub>Me<sub>6</sub>. It is a colourless liquid, soluble in organic solvents.<ref>Tamejiro Hiyama, Manabu Kuroboshi, "Hexamethyldisilane" Encyclopedia of Reagents for Organic Synthesis, 2001 John Wiley & Sons. {{doi|10.1002/047084289X.rh015}}</ref> '''Hexamethyldisilane''' (]<sub>2</sub>) is the ] with the formula Si<sub>2</sub>(CH<sub>3</sub>)<sub>6</sub>, abbreviated Si<sub>2</sub>Me<sub>6</sub>. It is a colourless liquid, soluble in organic solvents.<ref>Tamejiro Hiyama, Manabu Kuroboshi, "Hexamethyldisilane" Encyclopedia of Reagents for Organic Synthesis, 2001 John Wiley & Sons. {{doi|10.1002/047084289X.rh015}}</ref>
==Synthesis and reactions==
Hexamethyldisilane can be produced by ] of trimethylsilyl chloride in the presence of a reducing agent such as ]:
:{{chem2|2 Me3SiCl + 2 K -> Me3Si\sSiMe3 + 2 KCl}}
With an excess of the reductant, the alkali metal silyl derivative is produced:<ref>{{cite journal |doi=10.1016/0022-328X(88)80634-X|title=Efficient formation and cleavage of disilanes by potassium-graphite. Silylation with silyl metal reagents |year=1988 |last1=Fürstner |first1=Alois |last2=Weidmann |first2=Hans |journal=Journal of Organometallic Chemistry |volume=354 |pages=15–21 }}</ref>
:{{chem2|Me3Si\sSiMe3 + 2 K -> 2 Me3SiK}}


The Si-Si bond in hexamethyldisilane is cleaved by strong nucleophiles and electrophiles. Alkyl lithium compounds react as follows: The Si-Si bond in hexamethyldisilane is cleaved by strong nucleophiles and electrophiles. Alkyl lithium compounds react as follows:
:Si<sub>2</sub>Me<sub>6</sub> + RLi → RSiMe<sub>3</sub> + LiSiMe<sub>3</sub> :Si<sub>2</sub>Me<sub>6</sub> + RLi → RSiMe<sub>3</sub> + LiSiMe<sub>3</sub>

] gives ].<ref>{{cite journal|doi=10.1016/0040-4020(82)87002-6|title=Iodotrimethylsilane—a versatile synthetic reagent|year=1982|author1=Olah, G. |author2=Narang, S.C. |journal=]|volume=38|issue=15|pages=2225}}</ref> ] gives ].<ref>{{cite journal|doi=10.1016/0040-4020(82)87002-6|title=Iodotrimethylsilane—a versatile synthetic reagent|year=1982|author1=Olah, G. |author2=Narang, S.C. |journal=]|volume=38|issue=15|pages=2225}}</ref>
:Me<sub>3</sub>Si&minus;SiMe<sub>3</sub> + I<sub>2</sub> → 2 SiMe<sub>3</sub>I :Me<sub>3</sub>Si&minus;SiMe<sub>3</sub> + I<sub>2</sub> → 2 SiMe<sub>3</sub>I

Latest revision as of 19:50, 1 January 2023

Hexamethyldisilane
Skeletal formula of hexamethyldisilane
Ball-and-stick model
Space-filling model
Names
Preferred IUPAC name Hexamethyldisilane
Identifiers
CAS Number
3D model (JSmol)
Beilstein Reference 1633463
ChemSpider
ECHA InfoCard 100.014.465 Edit this at Wikidata
EC Number
  • 215-911-0
PubChem CID
RTECS number
  • JM9170000
UNII
UN number 1993
CompTox Dashboard (EPA)
InChI
  • InChI=1S/C6H18Si2/c1-7(2,3)8(4,5)6/h1-6H3Key: NEXSMEBSBIABKL-UHFFFAOYSA-N
SMILES
  • C(C)(C)(C)(C)C
Properties
Chemical formula Si2C6H18
Molar mass 146.39 g mol
Appearance Colourless liquid
Density 0.715 g/cm
Melting point 14 °C; 57 °F; 287 K
Boiling point 113 °C; 235 °F; 386 K
Refractive index (nD) 1.422
Thermochemistry
Std molar
entropy (S298) 		255.89 J K mol (at 22.52 °C)
Hazards
GHS labelling:
Pictograms GHS02: FlammableGHS07: Exclamation markGHS08: Health hazard
Signal word Danger
Hazard statements H225, H319, H334, H335
Precautionary statements 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 , 100 kPa). ☒N verify (what is  ?) Infobox references
Chemical compound

Hexamethyldisilane (TMS2) is the organosilicon compound with the formula Si2(CH3)6, abbreviated Si2Me6. It is a colourless liquid, soluble in organic solvents.

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:

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.

Me3Si−SiMe3 + I2 → 2 SiMe3I

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.
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