Silanes

<p>Ester Functional Trialkoxy Silane<br>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.<br>Hydrophilic Silane - Polar - Hydrogen Bonding<br>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.<br>2-[(Acetoxy(polyethyleneoxy)propyl]triethoxysilane; (Triethoxysilylpropylpolyethylene oxide)acetate<br>Viscosity: 50 cStFunctional PEG Silane (500-700 g/mol)PEO, Ester, Triethoxysilane termination utilized for hydrophilic surface modificationDual functional PEGylation reagentHydrogen bonding hydrophilic silaneUsed in microparticle surface modification<br></p>

<p>Alkyl Silane - Conventional Surface Bonding<br>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.<br>n-Decyltrichlorosilane; Trichlorosilyldecane; Trichlorodecylsilane<br></p>

<p>Olefin Functional Alkoxy Silane<br>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.<br>Dipodal Silane<br>Dipodal silanes are a series of adhesion promoters that have intrinsic hydrolytic stabilities up to ~10,000 times greater than conventional silanes and are used in applications such as plastic optics, multilayer printed circuit boards and as adhesive primers for ferrous and nonferrous metals. They have the ability to form up to six bonds to a substrate compared to conventional silanes with the ability to form only three bonds to a substrate. Many conventional coupling agents are frequently used in combination with 10-40% of a non-functional dipodal silane, where the conventional coupling agent provides the appropriate functionality for the application, and the non-functional dipodal silane provides increased durability. Dipodal silanes additives enhance hydrolytic stability, which impacts on increased product shelf life, ensures better substrate bonding and also leads to improved mechanical properties in coatings as well as composite applications.<br>1,2-Bis(triethoxysilyl)ethylene; 4,4,7,7-Tetraethoxy-3,8-dioxa-4,7-disiladec-5-ene<br>~80% trans isomerForms ethylene-bridged mesoporous silicas<br></p>

<p>Dialkyl Silane Reducing Agent<br>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.<br>Diphenylsilane; Dihydridodiphenylsilane<br>Converts amides to aldehydes in combination with Ti(OiPr)4Used in the preparation of silyl-substituted alkylidene complexes of tantalumUsed in the ionic reduction of enones to saturated ketonesUsed in the reductive cyclization of unsaturated ketonesReduces esters in the presence of zinc hydride catalystSilylates 1,2-diols in presence of tris(pentafluorophenyl)boraneReduces α-halo ketones in presence of Mo(0)Used in enantioselective reduction of iminesReduces thio esters to ethersSelective reduction of estersReduces esters to alcohols with Rh catalysisEmployed in the asymmetric reduction of methyl ketones and other ketonesReductively cleaves allyl acetatesExtensive review of silicon based reducing agents: Larson, G.; Fry, J. L. "Ionic and Organometallic-Catalyzed Organosilane Reductions", Wipf, P., Ed.; Wiley, 2007<br></p>

<p>Alkyl Silane - Conventional Surface Bonding<br>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.<br>1,5-Dichlorohexamethyltrisiloxane; Hexamethyldichlorotrisiloxane; 1,5-Dichloro-1,1,3,3,5,5-hexamethyltrisiloxane<br>ΔHvap: 47.7 kJ/molVapor pressure, 50 °C: 1 mm<br></p>

<p>Tri-substituted Silane Reducing Agent<br>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.<br>Triethylsilane; Triethylsilyl hydride; Triethylsilicon hydride<br>Viscosity: 4.9 cStDipole moment: 0.75 debyeSurface tension: 20.7 mN/mΔHform: -172 kJ/molΔHcomb: -5,324 kJ/molVapor pressure, 20 °: 40 mmSilylates tertiary alcohols in presence of tris(pentafluorophenyl)boraneSilylates arenes in presence of Ru catalyst and t-butylethyleneUsed in reductive cyclization of ynalsReadily converted directly to triethylsilyl carboxylatesUsed to reduce metal saltsEnhances deprotection of t-butoxycarbonyl-protected amines and tert-butyl estersUsed in the reductive amidation of oxazolidinones with amino acids to provide dipeptidesConverts aldehydes to symmetrical and unsymmetrical ethersUsed in the ‘in-situ’ preparation of diborane and haloboranesExtensive review of silicon based reducing agents: Larson, G.; Fry, J. L. "Ionic and Organometallic-Catalyzed Organosilane Reductions", Wipf, P., Ed.; Wiley, 2007<br></p>

<p>Volatile Higher Silane<br>Volatile higher silanes are low temperature, high deposition rate precursors. By appropriate selection of precursor and deposition conditions, silicon deposition can be shifted from amorphous hydrogenated silicon toward microcrystalline silicon structures. As the number of silicon atoms increases beyond two, electrons are capable of sigma–sigma bond conjugation. The dissociative adsorption of two of the three hydrogen atoms on terminal silicon atoms has a lower energy barrier.<br>Isotetrasilane; (Trisilyl)silane; 2-Silyltrisilane<br>PYROPHORICAIR TRANSPORT FORBIDDEN?Hvap: 32.5 kJ/molPrecursor for low temp. epitaxy of doped crystalline siliconEmployed in low temperature CVD of amorphous silicon<br></p>

<p>Diamino Functional Trialkoxy Silane<br>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.<br>N-(2-Aminoethyl)-3-aminopropyltriethoxysilane; N-[3-(Triethoxysilyl)propyl]-1,2-ethanediamine; N-[3-(Triethoxysilyl)propyl]-ethylenediamine<br>Primary amine with an internal secondary amine coupling agent for UV cure and epoxy systemsUsed in microparticle surface modificationSlower hydrolysis rate than SIA0591.0 and SIA0592.6<br></p>

<p>Hexamethylcyclotrisiloxane (HMCTS, D3)<br>Undergoes ring-opening anionic polymerizationReacts with three equivalents of an organolithium reagent to give derivatized dimethylsilanols<br></p>

<p>Alkyl Silane - Conventional Surface Bonding<br>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.<br>n-Octyltrimethoxysilane; Trimethoxysilyloctane<br>Viscosity: 1.0 cStVapor pressure, 75 °: 0.1 mmTreatment for particles used in non-aqueous liquid dispersionsTrialkoxy silane<br></p>

<p>Diamino Functional Trialkoxy Silane<br>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.<br>N-(6-Aminohexyl)aminomethyltriethoxysilane; N-[6-Triethoxysilyl)methyl]hexamethylethylenediamine<br>Primary amine and an internal secondary amine coupling agent for UV cure and epoxy systemsUsed in microparticle surface modification<br></p>

<p>Aldehyde Functional Trialkoxy Silane<br>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.<br>Triethoxysilylundecanal<br>Treated surface contact angle, water: 70°Long chain coupling agent for DNAProvides greater stability for coupled proteins than shorter alkyl homologsLong chain homolog of triethoxysilylbutyraldehyde (SIT8185.3)<br></p>