Silanes

Phenyl-Containing 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. Tri-substituted Silane Reducing Agent Organosilanes are hydrocarbon-like and possess the ability to serve as both ionic and free-radical reducing agents. These reagents and their reaction by-products are safer and more easily handled and disposed than many other reducing agents. The metallic nature of silicon and its low electronegativity relative to hydrogen lead to polarization of the Si-H bond yielding a hydridic hydrogen and a milder reducing agent compared to aluminum-, boron-, and other metal-based hydrides. A summary of some key silane reductions are presented in Table 1 of the Silicon-Based Reducing Agents brochure. Phenyldimethylsilane; Dimethylphenylsilane; Vapor pressure, 25 °C: 4 mmReacts with alcohols in presence of Wilkinson’s catalystUsed to prepare α-phenyldimethylsilyl esters with high enantioselectivityYields optically active reduction products with chiral Rh or Pd catalystsUndergoes 1,4-addition to pyridines forming N-silylated dihydropyridinesUsed in the fluoride ion-catalyzed reduction of aldehydes and ketones, and α-substituted alkanones to threo productsHydrosilylation of 1,4-bis(trimethylsilyl)butadiyne can go to the trisilyl allene or the trisilyl enyneErythro reduction of α-substituted alkanones to diols and aminoethanolsUsed to reduce α-amino ketones to aminoethanols with high stereoselectivityTogether with CuCl reduces aryl ketones, but not dialkyl ketonesUsed in the silylformylation of acetylenesExcellent reducing agent for the reduction of enones to saturated ketonesShows better selectivity than LAH in the reduction of oximes to alkoxyamines.Extensive review of silicon based reducing agents: Larson, G.; Fry, J. L. "Ionic and Organometallic-Catalyzed Organosilane Reductions", Wipf, P., Ed.; Wiley, 2007Summary of selective deprotection conditions is provided in Table 7 through Table 20 of the Silicon-Based Blocking Agents brochure

3-Isocyanatopropyltriethoxysilane; triethoxysilylpropylisocyanate Isocyanate functional trialkoxy silaneComponent in hybrid organic/inorganic urethanesCoupling agent for urethanes, polyols, and amines

Sivate A200 (Activated 3-Acryloxypropyltrimethoxysilane, 3-(trimethoxysilyl)propyl acrylate) Activated silane blend of acryloxypropytrimethoxysilane (SIA0200.0) and N-methyl-aza-2,2,4-trimethylsilacyclopentane (SIM6501.4)Reacts at high speed (seconds compared to hours)Does not require moisture or hydrolysis to initiate surface reactivityReacts with a greater variety of substratesPrimer and coupling agent for high speed UV cure systems (e.g. acrylated urethanes)Employed in optical fiber coatingsAnalog of methacryloxypropyltrimethoxysilane (SIM6487.4)Inhibited with BHT

Tipped PEG Silane (472-604 g/mol) 90% oligomersPEO, Trichlorosilane termination utilized for hydrophilic surface modificationPEGylation reagentHydrogen bonding hydrophilic silaneProvides protein antifouling surface

Tipped PEG Silane (363.83 g/mol) PEO, Trichlorosilane termination utilized for hydrophilic surface modificationDual functional PEGylation reagentForms self-assembled monolayers with "hydrophilic tips"Hydrogen bonding hydrophilic silane Related Products SIM6493.3: 2-[METHOXY(TRIETHYLENEOXY)]- (11-TRIETHOXYSILYL)UNDECANOATE, tech-95

Ester Functional Trialkoxy Silane Silane coupling agents have the ability to form a durable bond between organic and inorganic materials to generate desired heterogeneous environments or to incorporate the bulk properties of different phases into a uniform composite structure. The general formula has two classes of functionality. The hydrolyzable group forms stable condensation products with siliceous surfaces and other oxides such as those of aluminum, zirconium, tin, titanium, and nickel. The organofunctional group alters the wetting or adhesion characteristics of the substrate, utilizes the substrate to catalyze chemical transformations at the heterogeneous interface, orders the interfacial region, or modifies its partition characteristics, and significantly effects the covalent bond between organic and inorganic materials. Hydrophilic Silane - Polar - Hydrogen 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. Acetoxymethyltriethoxysilane; (Triethoxysilylmethyl)acetate Hydrolyzes to form stable silanol solutions in neutral water