Hexamethyldisilane

Hexamethyldisilane

Skeletal formula of hexamethyldisilane
Names
Preferred IUPAC name Hexamethyldisilane
Identifiers
CAS Number	1450-14-2^Y
3D model (JSmol)	Interactive image
Beilstein Reference	1633463
ChemSpider	66675^Y
ECHA InfoCard	100.014.465
EC Number	215-911-0
PubChem CID	74057
RTECS number	JM9170000
UNII	A7HH2E9DUB^Y
UN number	1993
CompTox Dashboard (EPA)	DTXSID2061698
InChI InChI=1S/C6H18Si2/c1-7(2,3)8(4,5)6/h1-6H3^Y Key: NEXSMEBSBIABKL-UHFFFAOYSA-N^Y
SMILES C[Si](C)(C)[Si](C)(C)C
Properties
Chemical formula	Si2C6H18
Molar mass	146.39 g mol^−1
Appearance	Colourless liquid
Density	0.715 g/cm^3
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 (S^⦵298)	255.89 J K^−1 mol^−1 (at 22.52 °C)
Hazards
GHS labelling:
Pictograms
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 [77 °F], 100 kPa). N verify (what is ^YN ?) Infobox references

Hexamethyldisilane (TMS₂) 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]

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.