Hexamethyldisilane

Hexamethyldisilane (TMS2) is the organosilicon compound with the formula Si2(CH3)6, abbreviated Si2Me6. It is a colourless liquid, soluble in organic solvents.[1]

Hexamethyldisilane
Skeletal formula of hexamethyldisilane
Ball-and-stick model
Space-filling model
Names
Preferred IUPAC name
Hexamethyldisilane
Identifiers
3D model (JSmol)
1633463
ChemSpider
ECHA InfoCard 100.014.465
EC Number
  • 215-911-0
RTECS number
  • JM9170000
UNII
UN number 1993
  • InChI=1S/C6H18Si2/c1-7(2,3)8(4,5)6/h1-6H3 checkY
    Key: NEXSMEBSBIABKL-UHFFFAOYSA-N checkY
  • C[Si](C)(C)[Si](C)(C)C
Properties
Si2C6H18
Molar mass 146.39 g mol−1
Appearance Colourless 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
255.89 J K−1 mol−1 (at 22.52 °C)
Hazards
GHS labelling:
GHS02: FlammableGHS07: Exclamation markGHS08: Health hazard
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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Infobox references

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]

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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