- Reaction of bis(trifluoromethyl)amino-oxyl with alkylchlorosilanes and allyldichloro(methyl)silane and of perfluoro-2,5-diazahexane 2,5-dioxyl with vinylsilanes and hydrolysis of the products
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Treatment of the silanes MeSiHCl2, Me2SiHCl and EtSiMeCl2 with the oxyl (CF3)2NO(.) (1) gives the substitution products (CF3)2NOSiMeCl2 (4) and (CF3)2NOSiMe2Cl (5), and a mixture of (CF3)2NOCHMeSiMeCl2 (8) and (CF3)2NOCH2CH2SiMeCl2 (9) (ratio 20:37), respectively, while the silane EtSiMe2Cl affords mainly the ester (CF3)2NO2CMe (7).Attack of oxyl 1 on the silane CH2=CHCH2SiMeCl2 results in both allylic substitution and addition to give the compounds CH2=CHCH(SiMeCl2)ON(CF3)2 (14) and (CF3)2NOCH2CH(CH2SiMeCl2)ON(CF3)2 (15) (ratio 56:40).Reaction of the dioxyl (.)ON(CF3)CF2CF2N(CF3)O(.) (2) with the vinylsilanes CH2=CHSiX3 (X3 = Me3, Cl3, MeCl2) gives mainly 1:1 copolymers n (17), although the cyclic 1:1 adduct (18) is also formed in low yield.Hydrolysis of the silanes 15, (CF3)2NOCH2CH(SiMeCl2)ON(CF3)2 (19a) and (CF3)2NOCH2CH(SiCl3)ON(CF3)2 (19b) affords the corresponding polysiloxanes 24 and 25, and the polysilsesquioxane 26, respectively; the polymers 25 and 26 undergo rearrangement of the type -CH(Si)ON(CF3)2 --> -CH(OSi)N(CF3)2 on storage.The 1:1 copolymers 17b (X3 = MeCl2) and 17c (X3 = Cl3) are also hydrolysed to the corresponding siloxane and silsesquioxane polymers.In contrast, hydrolysis of the compounds 4,5 and (CF3)2NOCH2CH(OSiX3)N(CF3)2 (20a; X3 = MeCl2) and (20b; X3 = Cl3) results in Si-O bond cleavage.
- Tipping, Anthony E.,Yadav, Rajendraprasad B.
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- CONVENIENT LABORATORY SYNTHESIS OF VINYLIC SILICON COMPOUNDS VIA THE REACTIONS OF ACETYLENE WITH HYDROSILANES CATALYZED BY GROUP-VIII METAL PHOSPHINE COMPLEXES
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The hydrosilylation of acetylene (HCCH) with trichlorosilane, triethoxysilane, methyldichlorosilane, methyldiethoxysilane and -hexyldichlorosilane in an inert solvent in the presence of various phosphine complexes of Group-VIII metals such as Ru, Rh, Pd and Pt, as well as chloroplatinic acid, was investigated.Among the complexes studied, RuCl2(PPh3)3, PtCl2(PPh3)2, RhCl(PPh3)3, RhH(PPh3)4 and Pt(PPh3)4 were found to be the catalysts of choice for the selective syntheses of vinyltrichlorosilane, vinyltriethoxysilane, methylvinyldichlorosilane, methylvinyldiethoxysilane and -hexylvinyldichlorosilane, respectively.
- Watanabe, Hamao,Asami, Muneo,Nagai, Yoichiro
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- SELECTIVE PREPARATION OF VINYL- AND ETHYL-FUNCTIONALIZED CHLOROSILANES
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A method of preparing an organosilicon compound via selective silylation of ethylene is disclosed. The method comprises reacting via silylation (A) a hydridochlorosilane compound and (B) ethylene in the presence of (C) a catalyst, thereby preparing the organosilicon compound. The silylation may be selectively conducted as a dehydrogenative coupling to prepare the organosilicon compound as a vinylchlorosilane compound, or as a hydrosilylation to prepare the organosilicon compound as an ethylchlorosilane compound. The catalyst (C) comprises a Ru(0) complex, and may be recycled for use in subsequent silylation reactions without purification. The organosilicon compound prepared according to the method is also disclosed.
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Paragraph 0094-0096
(2021/06/26)
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- Super-microporous silica-supported platinum catalyst for highly regioselective hydrosilylation
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Super-microporous micelle-templated platinum on silica catalysts were successfully prepared by an improved one-pot procedure, using a water/acetonitrile/n-dodecylamine mixture. The catalyst showed high surface area and narrow pore size and was further characterized by powder X-ray diffraction and inductively coupled plasma mass spectrometry. The unique super-microporous materials were proven to be highly active for the microwave-assisted hydrosilylation reaction of terminal alkenes or alkynes using dichloromethylsilane as silicon source. The super-microporous structure was beneficial for the control of hydrosilylation regioselectivity, as the selectivity to the β-adduct reached 99%. Moreover, the catalyst could be easily recovered by simple filtration and re-used seven times without appreciable loss of activity and selectivity.
- Hu, Wenbin,Xie, Huilin,Yue, Hangbo,Prinsen, Pepijn,Luque, Rafael
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- Hydrosilylation process for gaseous unsaturated hydrocarbons
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Organosilicon compounds are prepared by the addition reaction of a gaseous unsaturated hydrocarbon with a silane or siloxane containing at least one silicon-bonded hydrogen atom in the presence of a hydrosilylation catalyst in a liquid reaction medium. In this process the unsaturated hydrocarbon and optionally the silane or siloxane is dispersed into the liquid reaction medium by a jet eductor (also known as a venturi pump) device and the resultant gas-in-liquid dispersion is introduced into a bubble reactor.
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Page/Page column 5
(2010/02/16)
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- Silyl and σ-silane ruthenium complexes: Chloride substituent effects on the catalysed silylation of ethylene
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Silylation of ethylene by the chlorosilanes HSiMe2Cl and HSiMeCl2 was catalysed by the bis(dihydrogen) complex RuH 2(η2-H2)2(PCy3) 2 (1). Dehydrogenative silylation leading to the formation of the corresponding vinylsilanes was in competition with hydrosilylation. The rate and selectivity of the reactions were influenced by the number of chloro substituents and the ethylene pressure. A comparative mechanistic study was performed in toluene-d8 with the two chlorosilanes. Reaction of 1 with an excess of HSiMe2Cl (10 equiv.) produced the σ-silane complexes RuH2(η2-H2)(η2- HSiMe2Cl)(PCy3)2 (2Me2Cl), RuH 2(η2-HSiMe2Cl)2(PCy 3)2 (3Me2Cl) and the silyl complex RuCl(SiMe2Cl)(η2-H2)(PCy3) 2 (4Me2Cl), all characterised by multinuclear NMR spectroscopy. Complexes 2Me2Cl and 3Me2Cl adopt a cis configuration for the two bulky phosphine ligands as a result of stabilising SISHA (Secondary Interactions between Silicon and Hydrogen Atoms) interactions. Complex 4Me2Cl resulted from the stoichiometric reaction of HSiMe2Cl with 1 producing RuHCl(η2-H 2)(PCy3)2in situ which further reacted with evolution of H2 and formation of 4Me2Cl. When reacting 1 with 10 equiv. of HSiMeCl2, the corresponding complexes 3MeCl 2 and 4MeCl2 were detected as well as traces of 2MeCl 2. The reactivity toward ethylene was then examined. Under catalytic conditions (excess silane in toluene-d8, ethylene atmosphere) only two compounds could be characterised: free PCy3 and the new (η6-aryl)(disilyl) complexes of the general formula Ru(η6-C6D5CD3)(SiMe 3-nCln)2(PCy3) (6Me 3-nCln-d8, n = 1,2). The X-ray structure of 6MeCl2 was obtained on a single-crystal at 160 K. When only 2 equiv. of HSiMe2Cl were added, the ethylene(silyl) complex RuH(SiMe 2Cl)(C2H4)(PCy3)2 (7Me2Cl) was obtained in addition to the organic products resulting from catalytic hydrogenation, hydrosilylation and dehydrogenative silylation, i.e. C2H6 (major one), C2H3SiMe 2Cl and C2H5SiMe2Cl. In the case of 2 equiv. of HSiMeCl2, upon ethylene addition, 7MeCl2 was formed in minority compared to a new disilyl complex Ru(SiMeCl2) 2(PCy3)2 (8MeCl2) characterised by NMR spectroscopy and X-ray diffraction on a single crystal at 160 K. In 8MeCl2, a formal 14-electron species, stabilisation through two agostic C-H bonds of the cyclohexyl groups was ascertained by DFT calculations.
- Lachaize, Sebastien,Vendier, Laure,Sabo-Etienne, Sylviane
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experimental part
p. 8492 - 8500
(2011/01/08)
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- PALLADIUM COMPLEXES IN THE HYDROSILYLATION OF ACETYLENE
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The catalytic activities of triphenylphosphine-, trialkylphosphine-, and acetylacetone-palladium complexes in the hydrosilylation of acetylene with trichloro-, alkyldichloro-, triethyl, and triethoxy-silanes were investigated.The yields of the corresponding (triorganylsilyl)ethylenes and 1,2-bis(triorganylsilyl)ethanes (conditions: 70-80 deg C, solvent xylene) depend on the nature of the ligands on the palladium atom and the character of the substituents on the silicon atom in the hydride silane.
- Kopylova, L. I.,Pukhnarevich, V. B.,Voronkov, M. G.
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p. 276 - 278
(2007/10/02)
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- Hetero-?-Systems, 8. Silaethene
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By means of a combination of vacuum flash pyrolysis and matrix isolation silaethene (1a) and its simply substituted derivatives 1b-f can be prepared starting with precursors 9a-f of the silabicyclooctadiene type.Silaolefins 1a-f are stable in argon at 10 K and can be identified by their characteristic IR and UV spectra.
- Maier, Guenther,Mihm, Gerhard,Reisenauer, Hans Peter
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p. 2351 - 2368
(2007/10/02)
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- Macrocyclic polyether compounds
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Macrocyclic polyether "crown" compounds of the formula EQU1 WHEREIN T is a C2 -C3 alkylene, A is EQU2 R being H or C1 -C18 alkyl, R2 and R3 being independently C1 -C18 alkyl, C2 -C4 alkenyl, or C6 -C14 aryl; Q and Z are independently 1,2-arylene (or saturated derivatives thereof) or substituted 1,2-arylene (or saturated derivatives thereof); a is 0, 1, 2, or 3; b is an integer from 3 to 20; y is 1 or zero; x1, x2, x3, and x4 are integers independently selected to give a 15-60 atom ring. Such crown compounds are generally useful in the formation of complexes with ionic metal compounds, thus making it possible to use certain chemical reagents in media wherein they are normally insoluble.
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