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1.
Allyl and allenyl groups have been introduced into silicon systems by the allylation and allenylation of chlorosilanes using allyl bromide or propargyl bromide with indium. The allylation of chlorosilanes afforded a variety of aryl, aralkyl, and alkenyl substituted allylsilanes. By applying this method, the reactions of 1-bromo-3-methylbut-2-ene, 3-bromo-2-methylprop-1-ene and 3-bromobut-1-ene with chlorosilanes also proceed smoothly to give regioselectively allylic rearrangement products in good yields. Mediated by indium, dichlorosilanes (R 2SiCl 2) and trichlorosilanes (RSiCl 3) can either afford monoallylated silanes or diallylated silanes depending on the amount of allyl bromide and indium used. 相似文献
2.
Novel organylthio(alkoxy)silanes (I, II, III and XII) and organylthio(diethylamino)silanes (IV, V) are described. They were prepared by treating lithium or lead thiolates with the corresponding chlorosilanes or by cleavage of dimethylbis(diethylamino)silane with thiols. Phenylthiosilanes (Me 3SiSPh, III and XIII) furthermore can be obtained by reaction of chlorosilanes with benzenethiol in the presence of tertiary amines. The SiS bond of Me 3SiSPh is cleaved by chlorosilanes like Me 2Si(NEt 2)Cl or Me 2Si(OPr)Cl. This reaction is a convenient route to prepare compounds I and IV. The physical and chemical properties of the novel compounds were investigated. 相似文献
3.
The polymerizations of methyl methacrylate, styrene, and isobutyl vinyl ether with the binary systems of reduced nickel and chlorosilanes [(CH 3) nSiCl 4?n, n = 0–3] have been investigated. It was found that these systems could act as both radical and cationic initiators, depending on the nature of vinyl monomers used. The kinetic investigations indicated that methyl methacrylate polymerized via a radical mechanism, and the initiating activity of chlorosilanes decreased in the following order: SiCl 4 > CH 3SiCl 3 > (CH 3) 2SiCl 2 > (CH 3) 3SiCl ? 0. Cationic initiations were observed in the polymerizations of styrene and isobutyl vinyl ether. In the latter case, the activity of chlorosilanes was in the following order: (CH 3) 3SiCl > (CH 3) 2SiCl 2 > CH 3SiCl 3 ? SiCl 4. From the results obtained, a possible mechanism of selective initiation with these systems is proposed and discussed. 相似文献
4.
1-Trimethylsiloxyalkyl-bis(trimethylsilyl)silanes ( 5 ), obtained by a base induced isomerization of easily accessable 1-hydroxyalkyl-tris(trimethylsilyl)silanes ( 1 ) were hydrolized to give 1-hydroxyalkyl-bis(trimethylsilyl)silanes ( 6 ), which in presence of sodium hydride underwent a further 1,3-Si,O-trimethylsilyl migration resulting in the formation of 1-trimethylsiloxyalkyl-disilanes Me 3SiSiH 2–C(OSiMe 3)R 1R 2 ( 7 ). Under acidic conditions, the alkoxysilanes 5 isomerized in a Me 3Si/OSiMe 3 exchange under formation of the 1-trimethylsilylalkyldisiloxanes 10 , which were hydrolyzed affording the silanols 11 . Chlorination of the H-silanes 5 with CCl 4 gave the chlorosilanes 12 , which underwent rapid thermal isomerizations to give via the 1-chloroalkyldisiloxanes 13 the 1-trimethylsilylalkyl-chlorodisiloxanes 15 . Hydrolysis of 12 or 15 , resp., finally afforded the 1-trimethylsilylalkyl-silanediols 18 . Possible mechanisms of the various isomerization processes are discussed. The structures of the products described were elucidated by full spectral analyses. For 18 a the results of an X-ray structural analysis are given. 相似文献
5.
The three component reaction (Et 2N) 3P/CF 3Br/ R nSiCl 4-n (n = 1,2,3; RCH 3,Ph) gives CF 3-substituted organyl(chloro)silanes for the first time. Their genesis will be elucidated. 相似文献
6.
The preparation and alcoholysis of chiral chlorosilanes containing the nonacarbonyltricobaltcarbon cluster, RR′Si(Cl)CCo 3(CO) 9, is described. The alkoxy derivatives react with i-Bu 2AlH or BF 3 · Et 2O to give the corresponding silicon hydride or fluoride. Reaction of methylidynetricobalt nonacarbonyl with optically active silanes of germane gave the optically active cluster complexes R 1R 2R 3M *CCo 3(CO) 9 (M * = Si, Ge). These compounds react with phosphine to give the monosubstituted R 1R 2R 3M *CCo 3(CO) 8(PR 3 (M * = Si, Ge). The diastereomers have been resolved in the case of the MePhSi (Obornyl) CCo 3(CO) 9 complex. 相似文献
7.
Hydrosilylation of alkynes R 3MC≡CH (M = Si, Ge) afforded adducts whose subsequent treatment with ethynylmagnesium bromide gives polyunsaturated silanes and germanes R 3MCH=CHSi(C≡CH) 3. The latter can be subjected to the same transfomations to result in the unsaturated chain growth. 相似文献
8.
I.R. and Mass Spectroscopic Investigations on α,ω-Dihydrochloro Silanes H(SiCl 2) nH with n = 3?7 Mass spectra of α,ω-dihydrochlorosilanes H(SiCl 2) nH were analyzed respecting to their fragmentation. This shows, that the cleavage starts with the break of SiSi bonds, by preference in the middle of the chain. This is in accordance to the results of IR spectra which show very similar frequencies like perchlorooligo silanes. Thus, the lowest force constants of SiSi bondings in α,ω-dihydrochloro silanes, can be also expected in the middle of the chain. 相似文献
9.
The influence of reagents, solvent polarity, and temperature on the etherification of chlorosilanes ClCH 2SiCl 3, VinSiCl 3, PrSiCl 3, and Ph 3SiCl with ethanol was studied. Influence of reaction temperature on the ratio of the synthesized alkoxysilane and related side-product siloxane is revealed. Use of excess alcohol is shown to increase the content of siloxane. Introduction of FeCl 3 does not affect the synthesis. Solvents are shown to influence the reaction rate: the rate constant increases with increasing ? parameter of the solvent. The rate constant of etherification of chlorosilanes with ethanol falls in the series: ClCH 2SiCl 3 > VinSiCl 3 > PrSiCl 3. An explanation of the regularities is suggested. 相似文献
10.
A 1: 1 donor–acceptor complex between SiCl2 and HCl was detected by matrix IR spectroscopy. The existence of the complex was previously predicted theoretically in the course of analysis of mechanisms of chemical vapor deposition (CVD) processes involving chlorosilanes. The quantum chemical calculations at the G4(MP2) level confirmed the possibility of formation of only one stable complex upon the reaction of SiCl2 with HCl. In addition to the complex of the simplest composition, complexes of SiCl2 with HCl associates were observed upon matrix annealing. The only product formed upon the photolysis of the complexes of all types was trichlorosilane, a product of silylene insertion into the H–Cl bond. 相似文献
11.
Iminium cations generated by the coupling of aldehydes, N-trimethylsilylamines and TMSOTf or by the methylation of imines with MeOTf smoothly react with silanes of a general formula Me 3SiR f ( Rf = CF 3, CCl 2F, C 6F 5) to afford the corresponding tertiary amines having a fluorinated substituent. The key step, involving C-C bond formation, is promoted by NaOAc or KF in DMF as a solvent. 相似文献
12.
Closely following the procedure for the preparation of the base‐stabilized dichlorosilylene complex NHC Dipp⋅SiCl 2 reported by Roesky, Stalke, and co‐workers ( Angew. Chem. Int. Ed . 2009 , 48 , 5683–5686), a few crystals of the salt [NHC Dipp−H⋅⋅⋅Cl⋅⋅⋅H−NHC Dipp]Si(SiCl 3) 3 were isolated, aside from the reported byproduct [NHC Dipp−H +⋅⋅⋅Cl −], and characterized by X‐ray crystallography (NHC Dipp=N,N‐di(2,6‐diisopropylphenyl)imidazo‐2‐ylidene). They contain the weakly coordinating anion Si(SiCl 3) 3−, which was also obtained in high yields upon deprotonation of the conjugate Brønsted acid HSi(SiCl 3) 3 with NHC Dipp or PMP (PMP=1,2,2,6,6‐pentamethylpiperidine). The acidity of HSi(SiCl 3) 3 was estimated by DFT calculations to be substantially higher than those of other H‐silanes. Further DFT studies on the electronic structure of Si(SiCl 3) 3−, including the electrostatic potential and the electron localizability, confirmed its low basicity and nucleophilicity compared with other silyl anions. 相似文献
13.
The synthesis and complete characterization of functional, highly Lewis acidic tris(pentafluoroethyl)silanes as well as tetrakis(perfluoroalkyl)silanes Si(C 2F 5) 4 and Si(C 2F 5) 3CF 3 by direct fluorination is described. The reaction of SiCl 4 with LiC 2F 5 invariably affords (pentafluoroethyl)fluorosilicates. To avoid silicate formation by fluoride transfer from LiC 2F 5 the Lewis acidity of the silane has to be decreased by electron‐donating substituents, such as dialkylamino groups. The easily accessible Si(C 2F 5) 3NEt 2 is a valuable precursor for a series of tris(pentafluoroethyl)silanes. 相似文献
14.
Treatment of our reagent system (Et 2N) 3P/CFCl 3 with chloromethylsilanes (CH 3) nSiCl 4−n ( n = 1,2,3) yields the CFCl 2-substituted silanes (CH 3) nSiCl 3−n (CFCl 2). The missing Cl 3Si(CFCl 2) ( n = 0) can only be prepared by condensation of HSiCl 3 with cFCl 3 supported by Et 3N. 相似文献
15.
The detection of Me 3GeSiCl 3, a product from the Si 2Cl 6 cleavage of trimethylgermylphosphanes, as a useful new source of SiCl 2 moieties, as well as new trapping reactions of SiCl 2 and GeCl 2 with functional alkylidenephosphanes (Me 3Si) 2CPX (X = halide or dialkylphosphanyl [PRR ′; R = i-propyl, R ′ = t-butyl]) are reviewed. In the primary step of the reactions, insertion into the P-X bond is competing with addition to the PC bond. SiCl 2 and GeCl 2 insertions are followed by dimerisation reactions leading to new highly functional P-phosphanylalkylidenephosphanes, that may rearrange to diphosphenes like (XCl 2Si)(Me 3Si) 2C-PP-C(SiMe 3) 2SiCl 2X (X = F, Cl, P- i-Pr 2) or (Cl 3Ge)(Me 3Si) 2C-PP-C(SiMe 3) 2GeCl 2PRR ′ or/and react further with SiCl 2 or GeCl 2. Reaction of (Me 3Si) 2CP-PRR ′ (R = i-propyl, R ′ = t-butyl) with Me 3GeSiCl 3 leads in a very selective fashion to a complete PC double bond cleavage by unique double SiCl 2 addition with formation of a stable P-phosphanylphosphadisiletane. 相似文献
16.
A detailed quantum‐chemical study on the amine‐induced disproportionation reaction of perchlorinated silanes to neo‐Si 5Cl 12 is reported. The key intermediate in the resulting mechanistic scenario is a dichlorosilylene amine adduct, which is in tune with recent experimental findings. Yet, at variance with the generally accepted notion of silicon‐chain growth by concerted silylene insertion into Si?Cl bonds of lower silanes, the formation of neo‐Si 5Cl 12 follows more complex pathways. The reactivity is dominated by the Lewis–base character of the dichlorosilylene amine adduct and characterized by three elementary steps that bear close resemblance to the key elementary steps identified earlier for the chloride‐induced disproportionation of Si 2Cl 6. NBO and QTAIM analyses of the key reactive species SiCl 2 ? NMe 3 and SiCl 3? provide a rationale for these striking similarities. 相似文献
17.
The reactions of alkyn‐1‐yl(vinyl)silanes R 2Si[C?C‐Si(H)Me 2]CH?CH 2 [R = Me (1a), Ph (1b)], Me 2Si[C?C‐Si(Br)Me 2]CH?CH 2 (2a), and of alkyn‐1‐yl(allyl)silanes R 2Si[C?C‐Si(H)Me 2]CH 2CH?CH 2 (R = Me (3a), R = Ph (3b)] with 9‐borabicyclo[3.3.1]nonane in a 1:1 ratio afford in high yield the 1‐silacyclopent‐2‐ene derivatives 4a, b and 5a, and the 1‐silacyclohex‐2‐ene derivatives 6a, b, respectively, all of which bear a functionally substituted silyl group in 2‐position and the boryl group in 3‐position. This is the result of selective intermolecular 1,2‐hydroboration of the vinyl or allyl group, followed by intramolecular 1,1‐organoboration of the alkynyl group. In the cases of 4a, b, potential electron‐deficient Si? H? B bridges are absent or extremely weak, whereas in 6a,b the existence of Si? H? B bridges is evident from the NMR spectroscopic data ( 1H, 11B, 13C and 29Si NMR). The molecular structure of 4b was determined by X‐ray analysis. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
18.
Treatment of R2SiCl 2 ( R = Me, Ph) with 2‐aminopyridine in the presence of NEt 3 led to the formation of the bis( N‐2‐pyridylamino)silanes R2Si{NH(2‐Py)} 2, which were isolated as pale yellow solids. Crystal structure analyses revealed that both compounds exhibit tetrahedrally coordinated silicon atoms which are linked to two 2‐pyridylamido moieties and two organyl groups (Me or Ph). As a result of intermolecular hydrogen bonding between the NH groups and the pyridyl N atoms the R2Si{NH(2‐Py)} 2 molecules are catenated in the solid state. Treatment of R2Si{NH(2‐Py)} 2 with nBuLi afforded the corresponding amides R2Si{NLi(2‐Py)} 2, which were subsequently reacted with MCl 2 ( M = Sn, Pb) to give the dinuclear silylamides [{ R2Si( N‐2‐Py) 2M} 2]. Both the tin and the lead derivatives exhibit closely related molecular structures, in which the tin (or lead) atoms are linked to two amido N atoms and a pyridyl N atom in a distorted trigonal bipyramidal coordination mode. 相似文献
19.
Organylchlorosilanes, and also SiCl 4, decompose 1,1,3,3-tetra- and hexamethyl-disilazanes with formation of hitherto unknown organylchlorosilazanes of general formulas R 4–nSiCl n–1NHSiH(CH 3) 2 and R 4–nSiCl n–1NHSi(CH 3) 3 (n=2–4) in yields of 54–98%. The IR and mass spectra of the prepared compounds were studied.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1159–1162, May, 1991. 相似文献
20.
1, 1, 3, 3, 5, 5‐Hexavinyl‐1, 3, 5‐trisilacylohexane [Si(CH=CH 2) 2CH 2] 3 was synthesized and hydrosilylated with trichlorosilane to afford the first generation of a dendrimer. Conversion of this molecule with 18 Si–Cl functions on its surface with an excess of vinylmagnesium bromide yielded the 18‐fold vinylated dendrimer. The new compounds were identified by elemental analyses, multi‐nuclear NMR spectroscopy, and mass spectrometry. Crystal structures were obtained for [Si(CH=CH 2) 2CH 2] 3 and [Si(CH 2–CH 2SiCl 3) 2CH 2] 3. 相似文献
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