Tris(trimethylsilyl)silane

{{Chembox

| ImageFile = TTMSS.png

| ImageSize = 180 px

| ImageAlt =

| PIN = 1,1,1,3,3,3-Hexamethyl-2-(trimethylsilyl)trisilane

| OtherNames = TTMS, supersilane

|Section1={{Chembox Identifiers

| CASNo = 1873-77-4

| PubChem = 6327365

| ChemSpiderID = 109749

| UNII = NN5K4PS2OA

| StdInChI=1S/C9H27Si4/c1-11(2,3)10(12(4,5)6)13(7,8)9/h1-9H3

| StdInChIKey = SCHZCUMIENIQMY-UHFFFAOYSA-N

| SMILES = C[Si](C)(C)[Si]([Si](C)(C)C)[Si](C)(C)C

}}

|Section2={{Chembox Properties

| C=9|H=28|Si=4

| MolarMass =

| Appearance = colorless liquid

| Density = 0.806 g/cm³

| MeltingPt =

| BoilingPtC = 82-84

| BoilingPt_notes = 12 Torr

| Solubility = }}

|Section3={{Chembox Hazards

| MainHazards =

| FlashPt =

| AutoignitionPt = }}

}}

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.{{cite journal|title=Thirty Years of (TMS)₃SiH: A Milestone in Radical-Based Synthetic Chemistry|author=Chryssostomos Chatgilialoglu |author2=Carla Ferreri |author3=Yannick Landais |author4=Vitaliy I. Timokhin |journal=Chemical Reviews|year=2018|volume=118|issue=14|pages=6516–6572|doi=10.1021/acs.chemrev.8b00109|pmid=29938502|s2cid=49413857 }}

== Reactions ==

The compound can be prepared by protonation of tris(trimethylsilyl)silyl lithium, which is derived from tetrakis(trimethylsilyl)silane:{{cite journal|title=Tris(trimethylsilyl)silane|author=Joachim Dickhaut, Bernd Giese|journal=Org. Synth.|year=1992|volume=70|page=164|doi=10.15227/orgsyn.070.0164}}

:(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:{{cite journal|title=Spektroskopische Untersuchungen an Tris(trimethylsilyl)silan und -silan-d1|author=Bürger, H.; Kilian, W. |journal=Journal of Organometallic Chemistry|year=1969|volume=18|issue=2 |pages=299–306|doi=10.1016/S0022-328X(00)85398-X}}

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

Many coordination complexes have been prepared with (Me₃Si)₃Si⁻ (hypersilyl) ligand.{{cite journal |doi=10.1002/anie.200905950|title=Gold(I)-Mediated Silicon-Silicon Bond Metathesis at Room Temperature|year=2010|last1=Wilfling|first1=Marion|last2=Klinkhammer|first2=Karl W.|journal=Angewandte Chemie International Edition|volume=49|issue=18|pages=3219–3223|pmid=20349479}} Chalcogenide derivatives of (Me₃Si)₃SiLi are also well developed:{{cite book |doi=10.1002/9780470166444.ch4|chapter=The Chemistry of Metal Complexes with Selenolate and Tellurolate Ligands|title=Progress in Inorganic Chemistry|year=2007|last1=Arnold|first1=John|volume=43 |pages=353–417|isbn=978-0-470-16644-4}}

:3 Me₃SiLi + E → (Me₃Si)₃SiELi (E = S, Se, Te)