Potassium bis(trimethylsilyl)amide

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Potassium bis(trimethylsilyl)amide
KHMDS.png
Potassium bis(trimethylsilyl)amide unsolvated from crystal.png
Names
Preferred IUPAC name
Potassium 1,1,1-trimethyl-N-(trimethylsilyl)silanaminide
Other names
Potassium hexamethyldisilazide Potassium hexamethylsilazane [1]
Identifiers
3D model (JSmol)
AbbreviationsKHMDS
ChemSpider
ECHA InfoCard 100.102.263 OOjs UI icon edit-ltr-progressive.svg
PubChem CID
UN number 3263
  • InChI=1S/C6H18NSi2.K/c1-8(2,3)7-9(4,5)6;/h1-6H3;/q-1;+1 X mark.svgN
    Key: IUBQJLUDMLPAGT-UHFFFAOYSA-N X mark.svgN
  • C[Si](C)(C)N([K])[Si](C)(C)C
Properties
KSi
2
C
6
NH
18
Molar mass 199.4831 g mol−1
AppearanceWhite, opaque crystals
Reacts
Hazards
GHS labelling:
GHS-pictogram-acid.svg
Danger
H314 [2]
P280, P305+P351+P338, P310 [2]
Related compounds
Other cations
Lithium bis(trimethylsilyl)amide

Sodium bis(trimethylsilyl)amide

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Potassium bis(trimethylsilyl)amide (commonly abbreviated as KHMDS, Potassium(K) HexaMethylDiSilazide) or potassium hexamethyldisilazane [3] is the chemical compound with the formula ((CH3)3Si)2NK. It is a strong, non-nucleophilic base with an approximate pKa of 26 (compare to lithium diisopropylamide, at 36).[ citation needed ]

Contents

Structure

In the solid state, the unsolvated compound is dimeric, with two potassium and two nitrogen atoms forming a square. This compound is soluble in hydrocarbon solvents and conducts electricity poorly in solution and in the melt. This is attributed to very strong ion pairing. [4]

See also

Related Research Articles

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<span class="mw-page-title-main">Lithium diisopropylamide</span> Chemical compound

Lithium diisopropylamide is a chemical compound with the molecular formula LiN(CH 2)2. It is used as a strong base and has been widely utilized due to its good solubility in non-polar organic solvents and non-nucleophilic nature. It is a colorless solid, but is usually generated and observed only in solution. It was first prepared by Hamell and Levine in 1950 along with several other hindered lithium diorganylamides to effect the deprotonation of esters at the α position without attack of the carbonyl group.

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<span class="mw-page-title-main">Sodium bis(trimethylsilyl)amide</span> Chemical compound

Sodium bis(trimethylsilyl)amide is the organosilicon compound with the formula NaN(Si 3)2. This species, usually called NaHMDS, is a strong base used for deprotonation reactions or base-catalyzed reactions. Its advantages are that it is commercially available as a solid and it is soluble not only in ethers, such as THF or diethyl ether, but also in aromatic solvents, like benzene and toluene by virtue of the lipophilic TMS groups.

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<span class="mw-page-title-main">Trimethylsilyl chloride</span> Chemical compound

Trimethylsilyl chloride, also known as chlorotrimethylsilane is an organosilicon compound (silyl halide), with the formula (CH3)3SiCl, often abbreviated Me3SiCl or TMSCl. It is a colourless volatile liquid that is stable in the absence of water. It is widely used in organic chemistry.

Bis(trimethylsilyl)amine (also known as hexamethyldisilazane and HMDS) is an organosilicon compound with the molecular formula [(CH3)3Si]2NH. The molecule is a derivative of ammonia with trimethylsilyl groups in place of two hydrogen atoms. An electron diffraction study shows that silicon-nitrogen bond length (173.5 pm) and Si-N-Si bond angle (125.5°) to be similar to disilazane (in which methyl groups are replaced by hydrogen atoms) suggesting that steric factors are not a factor in regulating angles in this case. This colorless liquid is a reagent and a precursor to bases that are popular in organic synthesis and organometallic chemistry. Additionally, HMDS is also increasingly used as molecular precursor in chemical vapor deposition techniques to deposit silicon carbonitride thin films or coatings.

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HMDS may refer to:

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Bis(trimethylsilyl) sulfide is the chemical compound with the formula ((CH3)3Si)2S. Often abbreviated (tms)2S, this colourless, vile-smelling liquid is a useful aprotic source of "S2−" in chemical synthesis.

<span class="mw-page-title-main">Lithium bis(trimethylsilyl)amide</span> Chemical compound

Lithium bis(trimethylsilyl)amide is a lithiated organosilicon compound with the formula LiN(Si(CH3)3)2. It is commonly abbreviated as LiHMDS or Li(HMDS) (lithium hexamethyldisilazide - a reference to its conjugate acid HMDS) and is primarily used as a strong non-nucleophilic base and as a ligand. Like many lithium reagents, it has a tendency to aggregate and will form a cyclic trimer in the absence of coordinating species.

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Metal bis(trimethylsilyl)amides are coordination complexes composed of a cationic metal with anionic bis(trimethylsilyl)amide ligands and are part of a broader category of metal amides.

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References

  1. https://www.sigmaaldrich.com/ES/es/search/potassium-hexamethyldisilazane?focus=products&page=1&perpage=30&sort=relevance&term=potassium%20hexamethyldisilazane&type=product [ bare URL ]
  2. 1 2 Potassium bis(trimethylsilyl)amide, Sigma-Aldrich
  3. https://www.sigmaaldrich.com/ES/es/search/potassium-hexamethyldisilazane?focus=products&page=1&perpage=30&sort=relevance&term=potassium%20hexamethyldisilazane&type=product [ bare URL ]
  4. Tesh, Kris F.; Hanusa, Timothy P.; Huffman, John C. (1990). "Ion pairing in [bis(trimethylsilyl)amido]potassium: The x-ray crystal structure of unsolvated [KN(SiMe3)2]2". Inorg. Chem. 29 (8): 1584–1586. doi:10.1021/ic00333a029.