Tris(trimethylsilyl)silane

Tris(trimethylsilyl)silane

Names
Other names TTMS
Identifiers
CAS Number	1873-77-4
3D model (JSmol)	Interactive image
ChemSpider	109749
ECHA InfoCard	100.203.666
PubChem CID	6327365
UNII	NN5K4PS2OA
CompTox Dashboard (EPA)	DTXSID70940202
InChI InChI=1S/C9H27Si4/c1-11(2,3)10(12(4,5)6)13(7,8)9/h1-9H3 Key: SCHZCUMIENIQMY-UHFFFAOYSA-N
SMILES C[Si](C)(C)[Si]([Si](C)(C)C)[Si](C)(C)C
Properties
Chemical formula	C9H28Si4
Molar mass	248.663 g·mol−1
Appearance	colorless liquid
Density	0.806 g/cm3
Boiling point	82–84 °C (180–183 °F; 355–357 K) 12 Torr
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

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.

The compound can be prepared by protonation of tris(trimethylsilyl)silyl lithium, which is derived from tetrakis(trimethylsilyl)silane:

(Me₃Si)₄Si + MeLi → (Me₃Si)₃SiLi + Me₄Si

(Me₃Si)₃SiLi + HCl → (Me₃Si)₃SiH + LiCl

Alternatively, the reaction of trimethylsilyl chloride and trichlorosilane in the presence of lithium delivers the silane directly but in modest yield:

3 Me₃SiCl + HSiCl₃ + 6 Li → (Me₃Si)₃SiH + 6 LiCl

Many coordination complexes have been prepared with (Me₃Si)₃Si^- (hypersilyl) ligand.