2355-86-4

Upstream product

• 845-96-5 1,3-bis(4′-fluorophenyl)-1,1,3,3-tetramethyldisiloxane 
• 75-78-5 dimethylsilicon dichloride 
• 352-13-6 4-flourophenylmagnesium bromide 
• 460-00-4 1-Bromo-4-fluorobenzene 
• 1643-73-8 (4-fluorobenzyl)magnesium chloride 

Downstream Products

• 62806-41-1 Formyloxy-(p-fluorphenyl)-dimethylsilan 
• 134287-81-3 (4-Fluoro-phenyl)-dimethyl-[(S)-1-((R)-2-methyl-oxiranyl)-pentyloxy]-silane 
• 468732-05-0 (R,S)-2-(N,N-dimethylaminomethyl)ferrocenyl(4-fluorophenyl)dimethylsilane 
• 134287-83-5 erythro-2-methyl3-heptanal 
• 134287-82-4 threo-2-methyl-3-heptanal 
• 134287-82-4 (2R,3R)-3-[(4-Fluoro-phenyl)-dimethyl-silanyloxy]-2-methyl-heptanal 
• 134287-82-4 (2S,3R)-3-[(4-Fluoro-phenyl)-dimethyl-silanyloxy]-2-methyl-heptanal 
• 82475-42-1 N-(p-fluorophenyldimethylsilyl)-N,N-bis(2-chloroethyl)amine 
• 1833-31-4 benzyl(chloro)dimethylsilane 
• 22868-28-6 4-fluorophenyl(dimethyl)silanol 
• 1833-27-8 1,3-Dibenzyltetramethyldisiloxane 
• 845-96-5 1,3-bis(4′-fluorophenyl)-1,1,3,3-tetramethyldisiloxane 
• 6231-59-0 -<4-fluor-phenyl>-dimethyl-silan 
• 29886-50-8 p-Fluorbenzyl-dimethyl-allylsilicium 

Relevant academic research and scientific papers

Enantioselective 1,2-Anionotropic Rearrangement of Acylsilane through a Bisguanidinium Silicate Ion Pair

Highly enantioselective bisguanidinium-catalyzed tandem rearrangements of acylsilanes are reported. The acylsilanes were activated via an addition of fluoride on the silicon to form a penta-coordinate anionic silicate intermediate. The silicate then underwent alkyl or aryl group migration from the silicon atom to the neighboring carbonyl carbon atom (1,2-anionotropic rearrangement), followed by [1,2]-Brook rearrangement to provide the secondary alcohols in high yields with excellent enantioselectivities (up to 95% ee). The isolation of an α-silylcarbinol intermediate as well as DFT calculations revealed that the 1,2-anionotropic rearrangement occurred via a bisguanidinium silicate ion pair, which is the stereodetermining step. The chiral center formed is then retained without inversion through the subsequent [1,2]-Brook rearrangement. Crotyl acylsilanes were smoothly transformed into homoallylic linear crotyl alcohols with retention of E/Z geometry, and no branched alcohols were detected. This clearly suggested that the 1,2-anionotropic rearrangement occurred through a three-membered instead of a five-membered transition state.

Unbridged 1- and 2-substituted bis(silylindenyl) zirconium(IV) and hafnium(IV) dichloride complexes as catalyst precursors for ethylene polymerization

Twelve unbridged metallocene dichloride complexes of the types [1-(4-XC6H4SiMe2)-η5-Ind]2MCl2 and [2-(4-XC6H4SiMe2)-η5-Ind]2MCl2 (X = Me, MeO, F; M = Zr, Hf) with differently 1- and 2-substituted indenyl ligands have been synthesized, characterized and applied for catalytic ethylene polymerization. After activation with methylaluminoxane (MAO), all complexes are catalysts for ethylene polymerization. However, in nearly all cases, the species with the silyl substituent in the 1-position show much higher activities than those with the same substituent in 2-position of the indenyl moiety. For instance, the MAO activated complex bis(η5-1-(dimethyl-4-tolylsilyl)idenyl) zirconium(IV) dichloride (3), displayed an almost five times higher activity (3980 kg PE/mol cat.h) than the isomeric bis(η5-2-(dimethyl-4-tolylsilyl)indenyl) zirconium(IV) dichloride (19)/MAO catalyst (870 kg PE/mol cat.h). The same trend was observed for the para-fluorophenyl silyl indenyl complexes 23 and 17. This behavior may be explained in a way that the same silyl substituent in position 2 can exert more steric hindrance around the metal center compared to the 1-substituted analogues. The GPC characterization of the produced polyethylenes showed that some of the resins have a bimodal molecular weight distribution indicating at least two different active sites that are involved in the polymerization process.

LIQUID CRYSTAL COMPOSITION COMPRISING NOVEL SILICON CONTAINING COMPOUNDS AND LIQUID CRYSTAL DISPLAY DEVICE USING THE SAME

Disclosed are a silicon-containing compound, a liquid crystal composition comprising the same compound, and a liquid crystal display device comprising a liquid crystal layer prepared from the liquid crystal composition. The silicon-containing compound, which forms the liquid crystal composition, has low viscosity and high negative (?) dielectric anisotropy. Therefore, it is possible to provide a liquid crystal display device, which has a fast response time and can be driven at a low voltage.

LIQUID CRYSTAL COMPOSITION COMPRISING NOVEL SILICON CONTAINING COMPOUNDS AND LIQUID CRYSTAL DISPLAY DEVICE USING THE SAME

Disclosed are a silicon-containing compound, a liquid crystal composition comprising the same compound, and a liquid crystal display device comprising a liquid crystal layer prepared from the liquid crystal composition. The silicon-containing compound, which forms the liquid crystal composition, has low viscosity and high positive dielectric anisotropy. Therefore, it is possible to provide a liquid crystal display device, which has a fast response time and can be driven at a low voltage.

Liquid crystal composition comprising novel silicon containing compounds and liquid crystal display device using the same

Disclosed are a silicon-containing compound, a liquid crystal composition comprising the same compound, and a liquid crystal display device comprising a liquid crystal layer prepared from the liquid crystal composition. The silicon-containing compound, which forms the liquid crystal composition, has low viscosity and high positive dielectric anisotropy. Therefore, it is possible to provide a liquid crystal display device, which has a fast response time and can be driven at a low voltage.

Preparation, characterization and properties of dipolar 1,2-N,N-dimethylaminomethylferrocenylsilanes

A series of substituted 1,2-N,N-dimethylaminomethlyferrocenyl compounds were synthesized and characterized by 1H-NMR, 13C-NMR, 29Si-NMR, ES-MS, IR, UV - vis and 57Fe-M?ssbauer spectroscopy. The new (R,S)-2-(N,N-dimethylaminomethyl)ferrocenyl-(arly)silanes (R,S)-FcNSiMen(C6H4X)m (n = 2-0, m = 1, X = p-F (5); m = 2, X = p-F (6); m = 3, X = p-F (7) and m = 1, X = p-Br (14) were formed by the reaction of 2-dimethylaminomethylferrocenyllithium FcNLi (1) with chloroarylsilanes ClSi(Me)n (C6H4X)m (n = 2-0, m = 1, X = p-F (2); m = 2, X = p-F (3); m = 3, X = p-F (4) and m = 1, X = p-Br (13)). The treatment of 5, 6 and 14 with gaseous hydrogen chloride or picric acid resulted in the formation of the hydrochloride complexes 9, 10, 15 and the picrates 11, 12 and 16. The treatment of 14 with LiR or Mg and DMF resulted in the formation of (R,S)-2-(N,N-dimethylaminomethyl)ferrocenyl(4-formylphenyl)dimethylsilane (18). The crystal structures of 7, 12 and 15 were determined by single crystal X-ray analyses. 57Fe-M?ssbauer spectroscopy gives evidence of a significant electronic coupling between the ferrocenyl unit and the organic acceptor moiety of the molecules in the ground state.

Synthesis of siloxanes. XII. Cleavage of siloxanes by hydrogen chloride

1H NMR spectroscopy has been used in a kinetic study of the cleavage of siloxane bonds by hydrogen chloride in dioxane.The cleavages show an induction period which is associated with the autocatalytic effect of the water formed during the reaction.The kinetic behavior can be expressed in terms of a rate law that includes rate constants for cleavage by both dioxane*HCl (k1) and H2O*HCl (k2).The k'1 (k'1 = k1*-4) and k'2 (k'2 = k2*-3) values correlate with ?* values; thus ρ* values of -1.4 and -0.7 were obtained for k'1 and k'2, respectively.The ?* value of 0.35 that we previously derived for the Me3SiO group applies in this reaction.The reaction of 1,3-bis(p-methoxyphenyl)tetramethyldisiloxane with hydrogen chloride involves cleavage of silicon-aryl rather than Si-O bonds.

REACTIONS IN THE CHLOROSILANE-SILANOL-SILOXANE SYSTEM

We obtained the first ?*-values and ES-values for siloxy groups by spectroscopic and kinetic methods.Detailed mechanistic investigations are performed on the hydrolysis of chlorosilanes, the cleavage of Si-O-Si bonds by HCl, and the substituent exchange reaction between silanols and chlorosilanes.