COMMERCIAL
999-97-3

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1,1,1,3,3,3-HEXAMETHYLDISILAZANE, 98%

Product Code: SIH6110.0

Cas No: 999-97-3

R&D quantities:

1.5 kg
$99.00
25 g
$21.00

Interested in a Commercial Order?

Alkyl Silane - Conventional Surface Bonding

Aliphatic, fluorinated aliphatic or substituted aromatic hydrocarbon substituents are the hydrophobic entities which enable silanes to induce surface hydrophobicity. The organic substitution of the silane must be non-polar. The hydrophobic effect of the organic substitution can be related to the free energy of transfer of hydrocarbon molecules from an aqueous phase to a homogeneous hydrocarbon phase. A successful hydrophobic coating must eliminate or mitigate hydrogen bonding and shield polar surfaces from interaction with water by creating a non-polar interphase. Although silane and silicone derived coatings are in general the most hydrophobic, they maintain a high degree of permeability to water vapor. This allows coatings to breathe and reduce deterioration at the coating interface associated with entrapped water. Since ions are not transported through non-polar silane and silicone coatings, they offer protection to composite structures ranging from pigmented coatings to rebar reinforced concrete. A selection guide for hydrophobic silanes can be found on pages 22-31 of the Hydrophobicity, Hydrophilicity and Silane Surface Modification brochure.

ALD Material

Atomic layer deposition (ALD) is a chemically self-limiting deposition technique that is based on the sequential use of a gaseous chemical process. A thin film (as fine as -0.1 Å per cycle) results from repeating the deposition sequence as many times as needed to reach a certain thickness. The major characteristic of the films is the resulting conformality and the controlled deposition manner. Precursor selection is key in ALD processes, namely finding molecules which will have enough reactivity to produce the desired films yet are stable enough to be handled and safely delivered to the reaction chamber.

Trimethylsilyl Blocking Agent

Used as a protecting group for reactive hydrogens in alcohols, amines, thiols, and carboxylic acids. Organosilanes are hydrogen-like, can be introduced in high yield, and can be removed under selective conditions. They are stable over a wide range of reaction conditions and can be removed in the presence of other functional groups, including other protecting groups. The tolerance of silylated alcohols to chemical transformations summary is presented in Table 1 of the Silicon-Based Blocking Agents brochure.

Silane Cross-Coupling Agent

The cross-coupling reaction is a highly useful methodology for the formation of carbon-carbon bonds. It involves two reagents, with one typically being a suitable organometallic reagent - the nucleophile - and the other a suitable organic substrate, normally an unsaturated halide, tosylate or similar - the electrophile.

Hexamethyldisilazane; HMDS; HMDZ; Bis(trimethylsilyl)amine
  • Viscosity: 0.90 cSt
  • Low chloride grade available, SIH6110.1
  • ΔHcomb: 25,332 kJ/mol
  • ΔHvap: 34.7 kJ/mol
  • Dipole moment: 0.37 debye
  • Surface tension: 18.2 mN/m
  • Specific wetting surface: 485 m2/g
  • Vapor pressure, 50 °C: 50 mm
  • pKa: 7.55
  • Dielectric constant: 1000 Hz: 2.27
  • Ea, reaction w/SiO2 surface: 73.7 kJ/mole
  • Releases ammonia upon reaction
  • Versatile silylation reagent
  • Treatment of fumed silica renders it hydrophobic
  • Both trimethylsilyl groups used
  • Converts acid chlorides and alcohols to amines in a three-component reaction
  • Reacts with formamide and ketones to form pyrimidines
  • Silylations catalyzed by SIT8510.0 and other reagents
  • Nafion SAC-13 has been shown to be a recyclable catalyst for the trimethylsilylation of primary, secondary, and tertiary alcohols in excellent yields and short reaction times
  • Used to convert ketones to α-aminophosphonates
  • Lithium reagent reacts with aryl chlorides or bromides to provide anilines
  • Summary of selective deprotection conditions is provided in Table 7 through Table 20 of the Silicon-Based Blocking Agents brochure
  • Extensive review of silicon based cross-coupling agents: Denmark, S. E. et al. "Organic Reactions, Volume 75" Denmark, S. E. ed., John Wiley and Sons, 233, 2011
  • Boiling Point: 126-7°

    EINECS Number: 213-668-5

    Melting Point: <-76°

    Molecular Weight: 161.39

    Alternative Name: HMDS

    Specific Gravity: 0.7742

    Flashpoint: 12°C (54°F)

    HMIS Key: 2-4-1-X

    Hydrolytic Sensitivity: 7: reacts slowly with moisture/water

    Formula: C6H19NSi2

    Refractive Index: 1.4080

    TSCA: TSCA

    Application: Review of synthetic utility.1
    Review on organosilane protecting groups.2
    Converts acid chlorides and alcohols to amines in a three-component reaction.3
    Reacts with formamide and ketones to form pyrimidines.4
    Lithium reagent reacts w/ aryl chlorides or bromides to provide primary anilines.5
    Used to convert ketones to ?-aminophosphonates.6

    Reference: 1. Handbook of Reagents for Organic Synthesis, Reagents for Silicon-Mediated Organic Synthesis, Fuchs, P. L. Ed., John Wiley and Sons, Ltd., 2011, p. 317-319.
    2. Larson, G. L. “Silicon-Based Blocking Agents” Gelest, Inc. 2014.
    3. Li, H.-H. et al. Eur. J. Org. Chem. 2008, 3623.
    4. Tyagarajan, S.; Chakravarty, P. K. Tetrahedron Lett. 2005, 46, 7889.
    5. Lee, S.; Jorgensen, M.; Hartwig, J. F. Org. Lett. 2001, 3, 2729.
    6. Heo, Y. et al. Tetrahedron Lett. 2012, 53, 3897.

    Fieser: F&F: Vol. 1, p 427; Vol. 2, p 159; Vol. 5, p 323; Vol. 6, p 273; Vol. 7, p 167; Vol. 8, p 29; Vol. 9, p 234; Vol. 11, p 38; Vol. 12, p 239; Vol. 13, p 141; Vol. 14, p 300.

    Additional Properties: 325
    Ea, reaction w/SiO2 surface: 17.6 kcal/mole
    Specific wetting surface: 485 m2/g
    ?Hcomb: 6,052 kcal/mole
    ?Hvap: 8.3 kcal mole
    pKa: 7.55
    Dipole moment: 0.37 debye
    Dielectric constant: 1000 Hz: 2.27
    Surface tension: 18.2 mN/m
    Versatile silylation reagent; creates hydrophobic surfaces
    Vapor pressure, 50°: 50 mm