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Hydrosilylation Reaction (hydrosilylation + reaction)
Selected AbstractsChemInform Abstract: Remarkable Access to Fluoroalkylated Trisubstituted Alkenes via Highly Stereoselective Cobalt-Catalyzed Hydrosilylation Reaction of Fluoroalkylated Alkynes.CHEMINFORM, Issue 30 2009Tsutomu Konno Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Chiral Ligands with Pyridine Donors in Transition Metal Catalyzed Enantioselective Cyclopropanation and Hydrosilylation Reactions.CHEMINFORM, Issue 6 2001Giorgio Chelucci Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Convenient Enantioselective Hydrosilylation of Ketones Catalyzed by Zinc-Macrocyclic Oligoamine ComplexesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 7-8 2009Jadwiga Gajewy Abstract Chiral macrocyclic tetra- and hexamine macrocycles derived from trans -1,2-diaminocyclohexane (DACH) in complexes with diethylzinc efficiently catalyze the asymmetric hydrosilylation of aryl alkyl ketones with enantiomeric excess of the product up to 89%. The cyclic structure of the trianglamine ligand increases the enantioselectivity of the reaction, in comparison to the catalysis with the acyclic N,N, -dibenzyl-DACH ligand. Density functional theory (DFT) computations on the structures of ligand-zinc complexes and on the structures of these complexes with a coordinated acetophenone molecule allow us to rationalize the direction of the asymmetric induction of the hydrosilylation reaction as well as the superiority of the cyclic ligand compared to the acyclic one. This is the first example of asymmetric catalysis for the hydrosilylation reaction of ketones with the use of a readily available, inexpensive, and reusable macrocyclic trianglamine ligand. [source] Switchable thin-film surface prepared via a simple grafting-to method using a polystyrene- b -poly(2-vinylpyridine) copolymerJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 19 2006Ying Wang Abstract A polystyrene- b -poly(2-vinylpyridine) block copolymer containing a methylhydridosilane linking group was chemically grafted to an 8-trichlorosilyloctene monolayer via a simple one-step hydrosilylation reaction. The resulting Y-shaped thin film exhibited a low grafting density, which was characteristic of the grafting-to technique. To further reduce the miscibility of the two arms, methyl iodide was reacted with the poly(2-vinylpyridine) block to produce quaternary ammonium groups. The surfaces before and after quaternization were both solvent-switchable when subjected to block-selective solvents. Tensiometry, ellipsometry, attenuated total reflection/Fourier transform infrared, and atomic force microscopy were used to characterize the properties and morphology of both unquaternized and quaternized samples. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5608,5617, 2006 [source] Syntheses and characterizations of bis(trialkoxysilyl)oligoimides.JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 15 2001Abstract Novel crosslinkable fluorinated oligoimides were prepared in two steps. The first involved the synthesis of oligoimides terminated with nadic or allylic double bonds, and the second step was materialized either by a radical addition of mercaptotrialkoxysilane derivatives onto nadic double bonds or a hydrosilylation reaction of hydrogenotrialkoxysilane derivative onto allylic double bonds. Three kinds of crosslinking of the trialkoxysilane end groups were studied. The first kind entailed a thermal self-crosslinking of trialkoxysilane groups. The second process of crosslinking incorporated a bicomponent system,the crosslinked agent was 1,1,1-tris(4-hydroxyphenyl)ethane (TRIOH). The trialkoxysilane groups reacted with the hydroxyl,phenol groups of TRIOH to give thermally stable phenoxysilane bonds as well as a crosslinking network. The last method was also a bicomponent system; the oxalic acid was added into an oligoimide solution where by thermal treatment water was created. The water molecules hydrolyzed the trialkoxysilane groups into silanol groups that polycondensed into a crosslinked network following a sol,gel process. The mechanism of the different crosslinking reactions was investigated by Fourier transform infrared spectroscopy and solid-state 29Si NMR. The self-crosslinked material prepared from precursor ,,,-trimethoxysilyl fluorinated oligomer (Mn = 5500 g · mol,1) exhibited a 10 wt % loss temperature under air higher than 420 °C and a low birefringence (,n = 0.008) at 1.300 ,m. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2602,2619, 2001 [source] Synthesis and characterization of liquid crystalline elastomers bearing fluorinated mesogenic units and crosslinking mesogensPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 12 2009Fan-Bao Meng Abstract Several new side-chain liquid crystalline (LC) polysiloxanes and elastomers (IP - VIP) bearing fluorinated mesogenic units and crosslinking mesogens were synthesized by a one-step hydrosilylation reaction with poly(methylhydrogeno)siloxane, a fluorine-containing LC monomer 4,-undec-10-enoyloxy-biphenyl-4-yl 4-fluoro-benzoate and a crosslinking LC monomer 4,-(4-allyloxy-benzoxy)-biphenyl-4-yl 4-allyloxy-benzoate. The chemical structures and LC properties of the monomers and polymers were characterized by use of various experimental techniques such as FTIR, 1H-NMR, EA, TGA, DSC, POM and XRD. The effect of crosslinking mesogens on mesomorphic properties of the fluorinated LC polymers was studied as well. The obtained polymers and elastomers were soluble in many solvents such as toluene, tetrahydrofuran, chloroform, and so forth. The temperatures at which 5% weight loss occurred (Td) were greater than 250°C for all the polymers, and the weight of residue near 600°C increased slightly with increase of the crosslinking mesogens in the fluorinated polymer systems. The samples IP, IIP, IIIP and IVP showed both smectic A and nematic phases when they were heated and cooled, but VP and VIP exhibited only a nematic mesophase. The glass transition temperature (Tg) of polymers increased slightly with increase of crosslinking mesogens in the polymer systems, but the mesophase,isotropic phase transition temperature (Ti) and smectic A,nematic mesophase transition temperature (TS-N) decreased slightly. It suggests that the temperature range of the mesophase became narrow with the increase of crosslinking mesogens for all the fluorinated polymers and elastomers. In XRD curves, the intensity of sharp reflections at low angle decreased with increase of crosslinking mesogens in the fluorinated polymers systems, indicating that the smectic order derived from fluorinated mesogenic units should be destroyed by introduction of more crosslinking mesogens. Copyright © 2008 John Wiley & Sons, Ltd. [source] Synthesis and characterization of a novel soluble reactive ladder-like polysilsesquioxane with side-chain 2-(4-chloromethyl phenyl) ethyl groupsPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 8 2001Chunqing Liu Abstract A new kind of soluble structure-ordered ladder-like polysilsesquioxane with reactive side-chain 2-(4-chloromethyl phenyl) ethyl groups (L) was first synthesized by stepwise coupling polymerization. The monomer, 2-(4-chloromethyl phenyl) ethyltrichlorosilane (M), was synthesized successfully by hydrosilylation reaction with dicyclopentadienylplatinum(II) chloride (Cp2PtCl2) catalyst. Monomer and polymer structures were characterized by FT-IR, 1H -NMR, 13C -NMR, 29Si -NMR, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), vapor pressure osmometry (VPO) and X-ray diffraction (XRD). This novel reactive ladder-like polymer has promise potential applications as initiator for atom transfer radical polymerization, and as precursor for a variety of advanced functional polymers. Copyright © 2001 John Wiley & Sons, Ltd. [source] Synthesis and characterization of some novel silicon esters and their application as lubricant base stock solutionAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 12 2009Kanak Saxena Abstract A series of functional organosilanes and their esters were synthesized by the hydrosilylation reaction of SiH group-bearing organosilicon derivatives with maleic anhydride using Speier's catalyst and their esterification with long-chain alcohols in the presence of stannous oxide. These products have been characterized using elemental analysis, FT-IR, 1H, 13C and 29Si NMR. Viscosity, density, pour point, flash point and tribological properties of these compounds have also been evaluated. These esters have a pour point of <,60 °C, a flash point of ,200 °C (closed-cup) and excellent load carrying capacity. Copyright © 2009 John Wiley & Sons, Ltd. [source] Luminescent organo-polysiloxanes containing complexed lanthanide ionsAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 11 2009Lei Liu Abstract In this study, a type of polysiloxane with the ester as the functional side group was prepared via a hydrosilylation reaction. The functionalized polysiloxane was then allowed to complex with Tb3+ and Eu3+ ions. Fourier transform infrared, ultraviolet absorption spectra and 1H-NMR, 13C-NMR and 29Si-NMR spectra were used to confirm the modification. Differential scanning calorimetry and thermal gravity analysis were used to study the polysiloxane's thermal properties. The complexes' luminescence spectra were recorded, and narrow-width green and red emissions were achieved. Copyright © 2009 John Wiley & Sons, Ltd. [source] Electroactive Linear,Hyperbranched Block Copolymers Based on Linear Poly(ferrocenylsilane)s and Hyperbranched Poly(carbosilane)sCHEMISTRY - A EUROPEAN JOURNAL, Issue 36 2009Frederik Wurm Dipl.-Chem. Abstract A convenient two-step protocol is presented for synthesis of linear-hyperbranched diblock copolymers consisting of a linear, organometallic poly(ferrocenylsilane) (PFS) block and hyperbranched poly(carbosilane) (hbPCS) segments. Linear PFS diblock copolymers were synthesized through photolytic ring-opening polymerization of dimethyl[1]silaferrocenophane as the first block and methylvinyl[1]silaferrocenophane as the second. These block copolymers served as polyfunctional cores in a subsequent hydrosilylation polyaddition of different silane-based AB2 monomers. Three AB2 monomers (methyldiallylsilane; methyldiundecenylsilane, and ferrocenyldiallylsilane) were investigated; they introduced structural diversity to the hyperbranched block and showed variable reactivity for the hydrosilylation reaction. In the case with the additional ferrocene moiety in the ferrocenyldiallylsilane monomer, an electroactive hyperbranched block was generated. No slow monomer addition was necessary for molecular-weight control of the hyperbranching polyaddition, as the core had much higher functionality and reactivity than the carbosilane monomers. Different block ratios were targeted and hybrid block copolymers with narrow polydispersity (<1.2) were obtained. All the resulting polymers were investigated and characterized by size exclusion chromatography, NMR spectroscopy, cyclic voltammetry, and TEM, and exhibited strongly anisotropic aggregation. [source] Hydrosilylation of Ketone and Imine over Poly-N-Heterocyclic Carbene ParticlesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2009MeiXuan Tan Abstract N-Heterocyclic carbene (NHC)-catalyzed ketone/imine hydrosilylation, silane alcohol condensation and asymmetric ketone hydrosilylation reactions were demonstrated for the first time over solid, main-chain poly-NHC particles. The stable and robust poly-NHC particles were easily recovered, and exhibited good catalytic recyclability. A novel chiral induction protocol with a cheap and easily accessible secondary alcohol as the chiral source was also developed in this catalytic system. [source] Synthesis, functionalization and crosslinking reactions of poly[(silylene)-1,4-phenylenes] and poly[(silylene)-2,5-thienylenes] using silyl triflate intermediatesPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 11-12 2001Wolfram Uhlig Abstract Treatment of silylbis(triflates), RMeSi(OTf)2 (R,=,p-anisyl, allyl, NMe2) with 1,4-bis(bromomagnesium)benzene and 2,5-dilithiothiophene, respectively, give poly[(silylene)-1,4-phenylenes] and poly[(silylene)-2,5-thienylenes] in high yields. The RSi bonds could be cleaved selectively by triflic acid leading to triflate substituted derivatives. Conversions of these compounds with nucleophiles gave novel functionalized polymers. Pt-catalyzed hydrosilylation reactions between silicon-vinyl and silicon-hydrogen derivatives result in polymer networks which may serve as interesting preceramic materials. The structures of the polymers were proven by NMR spectroscopy (29Si, 13C, 1H). Results of thermogravimetric analysis (TGA), ultraviolet (UV) and conductivity measurements are given. Copyright © 2001 John Wiley & Sons, Ltd. [source] | |||||||||||||