1111-74-6Relevant articles and documents
Formation of organosilicon compounds 115: The applicability as precursors for β-SiC of carbosilanes resulting from the gas phase pyrolysis of methylsilanes
Toegel,Antony,Bill,Scheer, Petra,Eichhoefer,Fritz
, p. 125 - 131 (1996)
The thermal properties of polycarbosilanes from the gas phase pyrolysis of SiMe4, Me3SiCl, Me2SiCl2 and the polymeric (Me2Si-CH2)n has been investigated. They decompose above 400 °C to form volatile methylsilanes, H2, CH4, viscous carbosilanes and insoluble glassy products via condensation reactions. The ceramic yield is between 10 and 20 wt.% at about 900 °C and falls to only a few weight per cent when heating is continued to 1000 °C. The gas phase pyrolysis of Me2SiH2 at 650 °C produces plastic, meltable polycarbosilanes (PCS). Tempering the compounds to 900 °C gives a ceramic residue in 85% yield with Si:C:H 1:1.2:0.4. Heating this residue under thermal gravimetry (TG) conditions to 1500 °C (argon atmosphere) results in a further weight loss of 0.7% and formation of β-SiC. Silicon carbide is also formed when the PCS from Me2SiH2 (Si:C:H 1:1.5:2.5) are heated to 1400 °C, with a weight loss of 16.3% under nitrogen and one of 42% in vacuum.
Nucleophile induced ligand rearrangement reactions of alkoxy- and arylsilanes
Docherty, Jamie H.,Dominey, Andrew P.,Thomas, Stephen P.
, p. 3330 - 3335 (2019)
The ligand-redistribution reactions of aryl- and alkoxy-hydrosilanes can potentially cause the formation of gaseous hydrosilanes, which are flammable and pyrophoric. The ability of generic nucleophiles to initiate the ligand-redistribution reaction of commonly used hydrosilane reagents was investigated, alongside methods to hinder and halt the formation of hazardous hydrosilanes. Our results show that the ligand-redistribution reaction can be completely inhibited by common electrophiles and first-row transition metal pre-catalysts.
Hydrogenation of Silicium-Halogen-Compounds with Trialkylstannyl Chloride/Sodium Hydride
Hengge, E.,Grogger, C.,Uhlig, F.,Roewer, G.,Herzog, U.,Paetzold, U.
, p. 549 - 556 (1995)
Organotinchlorides of the general formula R3SnCl and R2SnCl2 (R = Me, n-Bu, Ph) can easily be converted into the corresponding hydrides R3SiH and R2SiH2 employing NaH in diethylene glycol dialkyl ethers.Using trialkyltinhydrides like Bu3SnH in combination with a catalyst (tertiary amines, N-heterocycles, phosphonium or ammonium salts), Si-Cl bonds in mono- and disilanes are hydrogenated.In the case of disilanes, Si-Si bond cleavage and concurrent hydrogenation can be afforded with strongly nucleophilic catalysts.Partial hydrogenation is also possible.The whole process can be run cyclically. - Keywords: Alkylstannylhydride; Hydrogenation; Organochlorsilane.
Electrochemical synthesis of symmetrical difunctional disilanes as precursors for organofunctional silanes
Grogger, Christa,Loidl, Bernhard,Stueger, Harald,Kammel, Thomas,Pachaly, Bernd
, p. 105 - 110 (2006)
Difunctional disilanes of the general type XR2SiSiR2X (1-5) (X = OMe, H; R = Me, Ph, H) have been synthesized by electrolysis of the appropriate chlorosilanes XR2SiCl in an undivided cell with a constant current supply and in the absence of any complexing agent. Reduction potentials of the chlorosilane starting materials derived from cyclic voltammetry measurements were used to rationalize the results of preparative electrolyses. Organofunctional silanes of the general formula MeO(Me 2)SiC6H4Y (6a-c, 7) were subsequently obtained by the reaction of sym-dimethoxytetramethyldisilane (1) with NaOMe in the presence of p-functional aryl bromides BrC6H4Y (Y = OMe, NEt2, NH2).
Mechanism of the Gas-Phase Thermolysis of Monomethylsilane
Neudorfl, P. S.,Lown, E. M.,Safarik, I.,Jodhan, A.,Strausz, O. P.
, p. 5780 - 5789 (1987)
The thermolysis of monomethylsilane (MMS) has been studied as a function of pressure (33-400 Torr), temperature (340-440 deg C), and conversion.Under conditions of very low (tipically, 0.5percent) conversion and in a carefully seasoned vessel the major products are H2 and dimethyldisilane (DMDS).Dimethylsilane (DMS) comprises ca. 5percent of the major products.MMS-d3 generates D2 exclusively.In the presence of ca. 10percent C2H4 the yields of H2 and DMDS are considerably reduced and both products follow first-order kinetics in their formation.Also, the formation of DMS is completely suppressed, and the Arrhenius parameters for the molecular process CH3SiH3 -> CH3H + H2 (1a) when determined from the rate of H2 production and from (CH3H + CH3SiH3 -> DMDS) production are log k1a = (15.02 +/- 0.10) - (63270 +/- 310) / 2.3RT and (14.87 +/- 0.12) - (63150 +/- 350) / 2.3RT, respectively.The molecular rate constant for H2, however, includes a small contribution from radical processes that cannot be completely suppressed.When the latter expression for k1a is used, the rate data for H2 is the unscavenged reaction can be fitted to a mechanism incorporating a second primary step, a slow, surface-catalyzed reaction generating H. and CH3SiH2. radicals , which then set up a short chain: CH3SiH2. + CH3SiH3 -> DMDS + H H + CH3SiH3 -> H2 + CH3SiH2. .On the basis of kinetic analysis of the data it is concluded that the chain is terminated linearly by CH3SiH2. radicals at the surface , with log A(s-1) = 11.7 and Ea ca. 32.3 kcal mol-1.The derived rate expression for the surface-catalyzed radical initation step CH3SiH3 -> Ch3SiH2. + H (1b) is log k1b = 12.7 - 57900/2.3RT.From the measured kinetic data the following themochemical values were derived: D(CH3H-H) = 73.5 kcal mol-1 and ΔHf(CH3H) = 51.9 kcal mol-1.
Activation of Si-Si and Si-H Bonds at a Platinum Bis(diphenylphosphanyl)ferrocene (dppf) Complex: Key Steps for the Catalytic Hydrogenolysis of Disilanes
Kall?ne, Sabrina I.,Laubenstein, Reik,Braun, Thomas,Dietrich, Maren
, p. 530 - 537 (2016)
Treatment of the platinum(0) complex [Pt(dppf)(nbe)] [1; dppf = 1,1′-bis(diphenylphosphanyl)ferrocene, nbe = norbornene] with the 1,2-dihydrodisilanes HPh2SiSiPh2H or HMe2SiSiMe2H gave [Pt(SiR2H)2(dppf)] (2, R = Ph; 4, R = Me) by oxidative addition of the Si-Si bond. The bis-silyl complexes 2 and 4 react with H2 to give [Pt(H)(SiR2H)(dppf)] (3, R = Ph; 5, R = Me) and H2SiR2. Adding HPh2SiSiPh2H to the hydrido silyl complex 3, which can also be prepared through Si-H activation of H2SiPh2 at 1, resulted in the regeneration of 2 as well as in the release of H2SiPh2. Treatment of HR2SiSiR2H with H2 (1.7 bar) in the presence of 2 or 4 under moderate conditions led to the catalytic formation of H2SiR2 with TONs up to 25. The catalytic conversions are distinguished by a high selectivity for the hydrogenolysis of the 1,2-dihydrodisilanes, and no significant tendency for redistribution reactions at Si was observed.
From carbon dioxide to methane: Homogeneous reduction of carbon dioxide with hydrosilanes catalyzed by zirconium-borane complexes
Matsuo, Tsukasa,Kawaguchi, Hiroyuki
, p. 12362 - 12363 (2006)
A mixture of a zirconium benzyl phenoxide complex and tris(pentafluorophenyl)borane is reported that catalyzes the hydrosilation reaction of carbon dioxide to generate methane via a bis(silyl)acetal intermediate. Copyright
Kinetics and Mechanism of the Reactions of O(3P) with SiH4, CH3SiH3, (CH3)2SiH2, and (CH3)3SiH
Horie, O.,Taege, R.,Reimann, B.,Arthur, N. L.,Potzinger, P.
, p. 4393 - 4400 (1991)
The reactions of O(3P) atoms with the silanes Me4-nSiHn (n = 1-4) have been investigated at room temperature in a discharge flow system with mass spectrometric detection and also in stationary photolysis experiments.Analysis of the end products provided conclusive evidence that the only primary process occuring in each case was the abstraction of hydrogen from the Si-H bond by the O atom leading to the formation of the OH and silyl radicals.The values of the rate constants obtained are k/10-13 cm3 s-1): k(O + SiH4) = 3.5, k(O + SiD4) = 1.4, k(O + MeSiH3) = 8.9; k(O + Me2SiH2) = 18.0, k(O + Me3SiH) = 30.6, and k(O + Me3SiD) = 16.0.The marked increase in rate constant with methylation is unexpected in view of the known similarity of the Si-H bond dissociation energy in SiH4 and the methylsilanes.A possible explanation is offered in terms of a reaction model involving partial charge transfer from Si to the attacking O, followed by proton transfer.
THERMOCHEMISTRY OF SILICON-CONTAINING COMPOUNDS PART 1.-SILICON-HALOGEN COMPOUNDS, AN EVALUATION
Walsh, Robin
, p. 2233 - 2248 (1983)
Literature data on the heats of formation of silicon-halogen compounds have been collected and reviewed.The coverage includes all tetravalent monosilicon compounds containing Si-H-X, where X is a single halogen, as well as the subhalides SiXn, where n = 1,2 or 3.The data are critically evaluated from the standpoints of bond addivity and general chemical reactivity of the species involved as well as by detailed consideration of individual studies.Earlier compilations or reviews are discussed.A set of recommended values (with uncertainties) is proposed.For the divalent species, SiX2, a self-consistent set of lone-pair stabilisation energies is obtained.
The vibrational spectra of germane and silane derivatives - XII. A reassignment of the dimethylhalosilanes
Clark, Allan J. F.,Drake, John E.,Hemmings, T. Raymond,Shen, Quang
, p. 127 - 136 (1983)
The i.r. and Raman spectra of the dimethylhalosilanes, Me2SiHZ and Me2SiDX (X = F, Cl, Br, I) have been recorded and the fundamental vibrations assigned.Analysis of the spectra of the deuterated compounds indicate that existing assignments for Me2SiHX are in error.
