- Siloxane bond formation by heterofunctional condensation of alkoxysilane and halogenosilane. Application to the preparation of copoly(tetramethyl-p-silphenylenesiloxane-dimethylsiloxane)
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Siloxane linkages are formed non-hydrolytically by the reaction of dihalogenosilanes with either dibenzylether, or dibenzyloxysilanes and dibenzhydryloxysilanes.The heterocondensation reaction is activated in the presence of NaI (in acetonitrile) or fluoride anions.This offers an alternative copolymerization route to the usual dehydrocondensation of SiOH-terminated species.Thus, the title copolymer was prepared by reaction of equimolar amounts of Me2Si(OCHPh2)2 and 1,4-bis(chlorodimethylsilyl)benzene at 100 deg C.The 29Si NMR spectrum supports a quasi-random sequence in the copolymer.Thermal stability is similar to that reported for an alternating microstructure, as inferred from thermogravimetric analysis. Key words: Siloxane; Polymer
- Corriu, R.J.P.,Leclercq, D.,Mutin, P.H.,Samson, H.,Vioux, A.
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- Iron-catalyzed chlorination of silanes
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A simple and highly efficient iron-catalyzed method for the chlorination of silanes has been developed. By use of 0.5-2% of the Fe(III)-based catalyst FeCl3 or Fe(acac)3 in the presence of 1-1.5 equiv of acetyl chloride as the chlorine donor, a large number of silanes, alkoxysilanes, and silanols were converted to the corresponding chlorosilanes in 50-93% yields. In contrast to earlier reported methods often suffering from expensive catalysts or use of stoichiometric metal salts, hazardous reagents, and reaction conditions, the presently described methodology allows benign reaction conditions and simple workup while using only catalytic amounts of a readily available and economically viable iron catalyst.
- Savela, Risto,Zawartka, Wojciech,Leino, Reko
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- Synthesis of heteroatomic bridged paracyclophanes
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Heteroatomic bridged paracyclophanes were obtained by two independent synthetic approaches. The required precursors consist of para R2SiCl (R = Me, iPr) substituted aromatic rings (2 and 4). They were subsequently functionalised by using NH3, [LiPH2(dme)] or LiAl(PH2)4. In the case of the Me-substituted species 2, the reaction with NH3 directly yielded the Si2N bridged paracyclophane 5. The Si2P incorporated derivative 10 was obtained by lithiation of p-C6H4(SiiPr2PH2)2 (9) and subsequent salt metathesis with the chlorosilane 4. The second approach involves the use of GaEt3 in the formation of four membered (GaPn)2 cycles (Pn = N, P). p-[C6H4{SiiPr2N(H)GaEt2}2]2 (11) and p-[C6H4{SiiPr2P(H)GaEt2}2]2 (12) represent the first examples of stable (GaPn)2cis isomers as the trans species did not appear in solution. Although 11 and 12 show a similar coordination pattern, they differ in the orientation of the aromatic systems: in the solid structure, 11 adopts a-for paracyclophanes so far unique-T-shape conformation of the phenyl rings, while 12 shows the predominant coplanar orientation. All cyclophanes were characterized by X-ray diffraction, elemental analysis, NMR and IR spectroscopy.
- Reuter,Maas,Reuter,Kilgenstein,Asfaha,Von H?nisch
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- Neutral-Eosin-Y-Photocatalyzed Silane Chlorination Using Dichloromethane
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Chlorosilanes are versatile reagents in organic synthesis and material science. A mild pathway is now reported for the quantitative conversion of hydrosilanes to silyl chlorides under visible-light irradiation using neutral eosin Y as a hydrogen-atom-transfer photocatalyst and dichloromethane as a chlorinating agent. Stepwise chlorination of di- and trihydrosilanes was achieved in a highly selective fashion assisted by continuous-flow micro-tubing reactors. The ability to access silyl radicals using photocatalytic Si?H activation promoted by eosin Y offers new perspectives for the synthesis of valuable silicon reagents in a convenient and green manner.
- Fan, Xuanzi,Xiao, Pin,Jiao, Zeqing,Yang, Tingting,Dai, Xiaojuan,Xu, Wengang,Tan, Jin Da,Cui, Ganglong,Su, Hongmei,Fang, Weihai,Wu, Jie
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supporting information
p. 12580 - 12584
(2019/08/16)
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- Silicon phenylene / carbosilane compound and preparation method thereof
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The present invention relates to the field of organic silicon, and more particularly relates to a silicon phenylene / carbosilane compound and a preparation method thereof. The invention discloses the silicon phenylene / carbosilane compound with the following molecular structural structure, wherein R1 is independently selected from the group consisting of C1-C5 alkyl, substituted alkyl, aryl and substituted aryl, R2 is independently selected from the group consisting of C1-C5 alkyl or substituted alkyl, aryl and alkenyl containing 1-5 carbon atoms, R3 is independently selected from the group consisting of C1-C12 alkyl or substituted alkyl, aryl and C1-C5 vinyl, and n is an integer from 1 to 50.
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Paragraph 0010
(2016/10/10)
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- High performance siloxane-containing polymers
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Catalytic cross-dehydrocoupling polymerization of silane and water, and deaminative polymerisation between silanol and aminosilane are used to synthesize a variety of silicon-containing polymers with controlled structure. n-Hexylamine-2-ethylhexoate was used to catalyze silanol condensation. Among transition metal derivatives investigated, Pd2(dba)s is the most active catalyst for the dehydrocoupling polymerisation, and deaminative polymerisation proceeded smoothly by heating. Optically active siloxane materials of branched structure were obtained from (S,S)-1,3-dimethyl-1,3- diphenyldisiloxanediol and (S,S)-1,5-di(1-naphthyl}-1,5-diphenyl-1,5-divinyl-3- methyltrisiloxane (>99% ee) as optically active building blocks.
- Kawakami, Yusuke,Imae, Ichiro,Oishi, Motoi,Seino, Makoto,Liu, Yang
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- PREPARATION OF ORGANOSILICON INTERMEDIATE AND THEIR DERIVATIVES IN A NOVEL GRIGNARD PROCESS
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A one-step process for the preparation of organosilicon intermediates. The organosilicon intermediates comprise a group which includes such intermediates as 1,4-bis(dimethylsilyl)benzene, 1,4-bis(dimethylchlorosilyl)benzene, and their derivatives. The process comprises: combining a dihalobenzene with magnesium metal in a co-solvent mixture of an ether and an organic solvent and reacting them with an organosilicon compound of the general formula, R2bHcSiXd. The resulting mixture is allowed to react to completion. The resulting mixture is passed through a filtration device. The liquid, now free of solid magnesium halide, is subjected to a separation technique to recover the subject organosilicon intermediates and their derivatives.
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- Siloxa-bridged-cyclophanes featuring benzene, thiophene and pyridine units
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Two octamethyldisiloxa-bridged [3.3]cyclophanes (1 and 2) and a dodecamethyltrissiloxa-bridged [3.3.3]-cage compound (3) were prepared by hydrolysis of the chlorosilyl monomers. This general route was also employed for the preparation of two octamethyldisiloxa-bridged [3.3]heterophanes featuring two thiophene (14) or pyridine (17) moities.
- Moores, Audrey,Defieber, Christian,Mezailles, Nicolas,Maigrot, Nicole,Ricard, Louis,Le Floch, Pascal
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p. 994 - 999
(2007/10/03)
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- Preparation, characterization and properties of dipolar 1,2-N,N-dimethylaminomethylferrocenylsilanes
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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.
- Beyer, Christian,B?hme, Uwe,Pietzsch, Claus,Roewer, Gerhard
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p. 187 - 201
(2007/10/03)
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- Efficient zirconocene-coupling of silicon-substituted diynes to polymers and macrocycles
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The zirconocene-coupling of diynes with internal silicon substituents, MeC≡CMe2SiArSiMe2C≡CMe (1: Ar = 1,4-C6H4; 2: Ar = 1,3-C6H4; 3: Ar = 1,3-C6H4; 3: Ar = 4,4'-C6H4C6H4), generates regiospecific polymers containing zirconacyclopentadiene in the main chain (5-7). These organometallic polymers hydrolyze cleanly to butadienediyl polymers of the type [Me2SiArSiMe2CH = CMeCMe = CH](n) (11-13), and polymer 5 reacts with iodine to give the iodine-containing polymer [1,4-Me2SiC6H4SiMe2C(I)=CMeCMe=C(I)](n) (14). The organometallic polymers undergo facile and high-yield degradations to macrocycles under mild conditions (refluxing tetrahydrofuran solution). The size and shape of the resulting macrocycles depend upon the nature of the diyne spacer group. Thus, polymers 5 and 7 containing parallel diyne units convert to the trimeric macrocycles [Me2SiArSiMe2C4Me2ZrCp2]3 (15: Ar = 1,4-C6H4; 24: Ar = 4,4'- C6H4C6H4), while polymer 6 gives the dimeric macrocycle [1,3- Me2SiC6H4SiMe2C4Me2ZrCp2]2 (18). The dimeric macrocycle [Me2SiC6H4SiMe2C6H4SiMe2C4Me2ZrCp2]2 (20) was obtained directly from the zirconocene coupling of Me2Si[(1,4-C6H4)- SiMe2(C≡CMe)]2 (4) by heating the reaction mixture to reflux. In a similar manner, the diyne Me2Si(C≡CMe)2 was converted in high yield to the hexameric macrocycle [Me2SiC4Me2ZrCp2]6 (22). The macrocycles 15, [1,4-Me2SiC6H4SiMe2C4Me2H2]3 (16), and 18 were characterized by single-crystal X-ray crystallography. Molecules of 15 adopt a nearly planar C3 macrocyclic structure with a cavity described by an average transannular Si···Si distance of 13.2 A?, while the hydrolyzed macrocycle 16 has a chair conformation. This conformation change results from conversion of cis diene groups in the zirconacyclopendiene fragments to trans diene groups in 16. The high- yield formation of macrocycles apparently results from the reversible nature of the alkyne-coupling reaction, which allows for a low-energy pathway to the smallest macrocycle possessing minimal ring strain.
- Mao, Shane S. H.,Liu, Feng-Quan,Tilley, T. Don
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p. 1193 - 1206
(2007/10/03)
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- Silylative Decarbonylation: A New Route to Arylsilanes
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A new synthetic procedure for the preparation of aromatic chlorosilanes via the palladium-catalyzed reaction of methylchlorodisilanes and aromatic acid chloride is described.The silylative decarbonylation process is solventless, can utilize low metal catalyst loadings (500-1000 ppm Pd), is carried out under moderate conditions (145 deg C), and selectively gives aromatic chlorosilanes in good yield, generally 60-85percent.The procedure is tolerant of a variety of aromatic substituents, for example, alkyl, halo, nitro, cyano, imide, acid anhydride, etc., and the synthesis ofseveral new substituted aromatic chlorosilanes containing benzoyl chloride and phthalic anhydride moieties is described.Chloromethyldisilane starting reagents are available from the direct reaction of methyl chloride and silicon, making this methodology an attractive synthetic route to functionalized aromatic chlorosilanes.
- Rich, Jonathan D.
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p. 5886 - 5893
(2007/10/02)
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- REACTIONS OF TELLURIUM(IV) CHLORIDES WITH SOME ORGANOSILICON HYDRIDES
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The reactions of several organosilicon hydrides PhnSiH(4-n), n = 1, 2; R3SiH, R3 = Ph3, Ph2Me, PhMe2, (n-C6H13)3; (p-Me2HSi)2C6H4, with TeCl4 in benzene resulted in the formation of tellurium metal and chlorosilanes in 75-90percent yields.Similar reactions with aryltellurium trichlorides (RTeCl3, R = Ph, p-MeOC6H4, p-EtOC6H4) proceeded in two different ways.On stirring at room temperature for 6-8 h, diaryl ditellurides and chlorosilanes were obtained in 70-95percent yields whereas on refluxing for 6-10 h, tellurium powder and diaryltellurium dichlorides were obtained along withthe chlorosilanes in 80-95percent yields.Diaryltellurium dichlorides (R2TeCl2, R = Ph, p-MeOC6H4) did not react readily with PhSiH3 nor with Ph3SiH.
- Chadha, Raj K.,Drake, John E.,Neo, Mary K. H.
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