Phenyltrimethoxysilane

Oxane bonds, M—O—Si, are hydroly2ed during prolonged exposure to water but reform when dried. Adhesion in composites is maintained by controlling conditions favorable for equiUbrium oxane formation, ie, maximum initial oxane bonding, minimum penetration of water to the interface, and optimum morphology for retention of silanols at the interface. The inclusion of a hydrophobic silane, such as phenyltrimethoxysilane [2996-92-17, with the organofunctional silane increases thermal stabiUty of the silane and make the bond more water resistant (42). 

Silane coupling agents may contribute hydrophilic properties to the interface, especially when amino functional silanes, such as epoxies and urethane silanes, are used as primers for reactive polymers. The primer may supply much more amine functionality than can possibly react with the resin at the interphase. Those amines that could not react are hydrophilic and, therefore, responsible for the poor water resistance of bonds. An effective way to use hydrophilic silanes is to blend them with hydrophobic silanes such as phenyltrimethoxysilane. Mixed siloxane primers also have an improved thermal stability, which is typical for aromatic silicones [42]. 

Phenyltrimethoxysilane 75 is activated by fluoride anion to 76, which undergoes palladium-catalyzed couphng with 4-methyliodobenzene 77 to give a nearly quantitative yield of 4-methyldiphenyl 78 [90]. Such Heck-, Stille-, or Suzuki-type C-C coupling of arylsilanes such as 75 were recently reviewed [91] (Scheme 2.12). 

In addition, commercially available phenyltrimethoxysilane has been successfully cross-coupled with heteroaryl bromides including both bromopyridines and bromothiophenes [105], Both 2-bromopyridine and 3-bromopyridine were coupled with phenyltrimethoxysilane to give the corresponding phenylpyridines in 76% and 62% yield, respectively. Employing phenyl tris(trifluoroethoxy)silane, a siloxane with electron-withdrawing groups, did not improve the yields. 

In this case, the material s specific chiral cavities are created by utilizing phenyltrimethoxysilane and TMOS as the monomers and the chiral cationic surfactant A-dodecyl-TV-methylephedirnium (DMB) as template,... 

Thin sol gel ORMOSIL-zirconia films successfully inhibit magnesium corrosion (Figure 4.11). The film obtained by combining sol-gel monomers phenyltrimethoxysilane (PTMOS) and zirconium(iv) tetra-1-propoxide (ZrTPO) exhibits superior corrosion inhibition as compared with other films,13 while the ZrTPO-based film alone does not show significant corrosion inhibition, and the PTMOS-based film provides only moderate protection. The films are prepared by the traditional acid-or base-catalysed hydrolysis and condensation, depositing first the PTMOS film followed by the ZrTPO-based film. 

The CpMo(CO)3 moiety has also been grafted onto mesoporous materials, MCM-41 [25], MCM-48 [25], and SBA-15 [38], previously modified by the use of p-(iodomethyl)phenyltrimethoxysilane (Scheme 8). 

Scheme8 [Mo(CO)3]Na tethering on ap-(iodomethyl)phenyltrimethoxysilane-functional-ised MCM...

A round-bottom flask was charged with 15 ml of a toluene and water, 2 1, respectively, phenyltrimethoxysilane (0.02 mol), p-chloromethylphenyltrimethoxysilane (0.02 mol), and methanesulfonic acid (5 mol%) and then stirred at ambient temperature for 12 hours. The organic layer was isolated, concentrated, and then added dropwise to a large quantity of -hexane. The precipitated solid was filtered, dried, and the product isolated in 93 % yield having an Mn of 1300 Da with a poly dispersity index (PDI) of 1.25. 

A sample has been prepared starting from phenyltrimethoxysilane (PTMS) and tetramethoxysilane (TMOS) in a 1 4 molar ratio. The corresponding X-ray pattern shows the presence of a hexagonal phase with no evidence of cubic phase formation. 

In order to counteract the effect of water absorption in the interphase region, hydrophobic substituents were added to the coupling agent [5]. Methyltri-methoxysilane G, vinyltrimethoxysilane A, and 3-chloropropyltrimethoxysilane B are good sources of hydrophobic character, but phenyltrimethoxysilane I gives a good combination of hydrophobic character, thermal stability, and polymer compatibility. 

Figure 2. Transmission 1R spectra of the silanes used in the primer. (A) Phenyltrimethoxysilane (B) 2-aminoethyl-3-aminopropyltrimethoxysilane.

Silanetriols eluded all attempts at their isolation until a few years ago when Tyler (88) prepared phenylsilanetriol from phenyltrimethoxysilane and dilute acetic acid at about 10°. More recently Takiguchi (82) obtained this substance from phenyltrichloiosilane in the presence of aniline. Andrianov, Zhdanov and Morganova (7) obtained dichloro-phenylsilanetriol by hydrolyzing the triacetoxysilane. The interesting tetrol, bis-(dichlorophenyl)-disiloxanetetrol, was similarly obtained from bis-(dichlorophenyl)-tetraacetoxydisiloxane. 

The first monobenzosilatrane, 1-phenylbenzosilatrane (161), was synthesized in good yield by treatment of phenyltrimethoxysilane with 2-aminophenol and ethylene oxide... 

The Hiyama cross-coupling of organosilanes is attractive as the intermediates are often easy to prepare and the silicon by-products are environmentally benign. A one-pot synthesis of 2-aryl-3-methylpyridines from 2-bromo-3-methylpyridine was developed (Scheme 25) <2003JOM58>. Both 2- and 3-bromopyridine cross-couple with phenyltrimethoxysilane to afford the corresponding phenylpyridines in good yield <19990L2137>. 

Useful chemical reactions have been carried out in the nano-sized cavity, as illustrated by the in situ isolation of a labile cyclic siloxane trimer (Fig. 20.3.19). In the first step, three to four molecules of phenyltrimethoxysilane enter the cage and are hydrolyzed to siloxane molecules. Next, condensation takes place in the confined environment to generate the cyclic trimer SiPh(0H)0- 3, which is trapped and stabilized in a pure form. The overall reaction yields an inclusion complex [ SiPh(0H)0- 3 c Pt(bipy) 6L4](N03)i2-7H20, which can be crystallized from aqueous solution in 92% yield. The all-cis configuration of the cyclic siloxane trimer and the structure of the inclusion complex have been determined by NMR and ESI-MS. 

The combination Pd(OAc)2/IPr HC1 in a dioxane/THF mixture has been reported to be efficient for the coupling of aryl bromides and activated aryl chlorides with phenyltrimethoxysilane (Table 3) [90]. 

Table 3 Pd/IPr-catalyzed coupling of aryl halides with phenyltrimethoxysilane...

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