1627-98-1Relevant articles and documents
THERMAL AND PHOTOCHEMICAL BEHAVIOR OF 2-SILA- AND GERMA-CYCLOPENTANONE
Hassner, Alfred,Soderquist, John A.
, p. 429 - 432 (1980)
Pyrolysis and photolysis of the first examples of five-membered ring sila and germa ketones 2 is reported.The photolysis of 2a leading to a cyclic acetal via a siloxycarbene is contrasted to the behavior of the germa analog 2b wich gives ring cleavage via a ketene intermediate.
Kinetics of Addition of 2-Methyl-2-silapropene to Hydrogen Chloride, Hydrogen Bromide, and Oxygen
Davidson, Iain M. T.,Dean, Christopher E.,Lawrence, F. Timothy
, p. 52 - 53 (1981)
2-Methyl-2-silapropene adds rapidly to hydrogen chloride and hydrogen bromide in the gas phase to form the corresponding trimethylsilyl halide, and to molecular oxygen to form dimethylsilanone; Arrhenius parameters for these reactions have been measured.
The Infra-red Multiphoton-induced Decomposition of Silicon-containing Four-membered Rings. A New Source of Silaolefins
Frey, Henry M.,Kashoulis, Annoula,Ling, Lee Mei,Lodge, Susan P.,Pidgeon, Ivy M.,Walsh, Robin
, p. 915 - 917 (1981)
The title process is shown to be a new source of 2-methyl-2-silapropene for which some relative rate constants are reported.
Laser-powered homogeneous pyrolysis of 1,1-dimethyl-1-silacyclobutane in the presence of some common monomers
Pola, Josef,Cukanova, Dana,Minarik, Milan,Lycka, Antonin,Tlaskal, Jaroslav
, p. 23 - 34 (2007/10/02)
Laser-induced homogeneous pyrolysis of 1,1-dimethyl-1-silacyclobutane yields 1,1,3,3-tetramethyl-1,3-disilacyclobutane and ethene as major products.In the presence of vinyl acetate, allyl methyl ether, acrolein, methyl vinyl ether, methyl acrylate or meth
L'electrosynthese, une alternative pour la synthese de polycarbosilanes
Bordeau, M.,Biran, C.,Pons, P.,Leger, M.-P.,Dunogues, J.
, p. C21 - C24 (2007/10/02)
The electrochemical reduction of chloromethyldimethylchlorosilane affords polycarbosilanes in high yields and this route constitutes a competitive route to 1,1,3,3-tetramethyl-1,3-disilacyclobutane formed in 34percent crude yield.The solvent mixture was varied to yield its precursor, Cl(CH2SiMe2)2Cl, in 43percent yield after distillation, while electrosynthesis in the presence of dimethyldichlorosilane provided bis(dimethyl-chlorosilyl)methane, another polycarbosilane precursor, in 60percent yield after distillation.
Stationary and Pulsed Photolysis and Pyrolysis of 1,1-Dimethylsilacyclobutane
Brix, Th.,Arthur, N. L.,Potzinger, P.
, p. 8193 - 8197 (2007/10/02)
A study of the photolysis of 1,1-dimethylsilacyclobutane at 147 - 214 nm shows that of the four primary processes identified the predominant mode of decomposition is to C2H4 and dimethylsilaethene.Evidence from experiments in the presence of SF6 suggests that the dimethylsilaethene is formed initially in a vibrationally excited state: +hν -> Me2SiCH2v + CH2=CH2.Laser pulsed photolysis experiments at 193 nm have been carried out to measure tha absorption spectrum of Me2SiCH2, its absorption cross section, and the rate constant for Me2SCH2 combination: 2Me2SiCH2 -> (Me2SiCH2)2.The values obtained are ? (240 nm, base e) = (1.0 +/- 0.2)E-17 cm2 and k7 = (3.3 +/- 0.8)E-11 cm3 s-1.The kinetics of the pyrolysis of have also been reexamined, yielding the following rate constant expressions: k1/(s-1) = E(15.46 +/- 0.13) exp(-(31043 +/- 218)/T) and k-1/k71/2/(cm3/2s-1/2) = E(-7.0 +/- 0.3) exp(-(7850 +/- 300)/T).From these results, the heat of formation, ?-bond energy, and entropy of Me2SiCH2, have been deduced: ΔHfθ (g, 298 K) = 36 +/- 7 kJ mol-1, B? = 157 +/- 11 kJ mol-1, and Sθ(g, 298 K) = 332 +/- 8 J mol-1 K-1.
SILYL AND SILYLMETHYL RADICALS, SILYLENES, SILA-ALKENES, AND SMALL RING SILACYCLES IN REACTIONS OF ORGANOCHLOROSILANES WITH ALKALI METAL VAPOURS
Gusel'nikov, L. E.,Polyakov, Yu. P.,Volnina, E. A.,Nametkin, N. S.
, p. 189 - 204 (2007/10/02)
Dehalogenation of the organochlorosilanes Me3SiCl (I), Me2PrSiCl (II), Me3SiSiMe2Cl (III), Me3SiCH2SiMe2Cl (IV), ClCH2SiMe3 (V), ClCH2SiMe2SiMe3 (VI), ClCH2Me2SiSiMe2CH2Cl (VII), Me2SiCl2 (VIII), MePrSiCl2 (IX), Me3SiCH2SiMeCl2 (X), Me3SiCH2CH2SiMeCl2 (XI), Me3SiCH2CH2CH2SiMeCl2 (XII), ClCH2Si(H)MeCl (XIII), ClCH2SiMe2Cl (XIV), ClMe2SiSiMe2Cl (XV), ClCH2CH2CH2Si(H)MeCl (XVI), ClCH2CH2CH2SiMe2Cl (XVII), ClCH2CH2OSiMe2Cl (XVIII), ClMe2SiCH2SiMe2Cl (XIX), ClMe2SiCH2CH2SiMe2Cl (XX), and ClMe2SiCH2CH2CH2SiMe2Cl (XXI) with K/Na alloy vapours at 0.1-1 Torr and 300-320 deg C yields products derived from the reactions of short-lived intermediates, such as silyl and silylmethyl radicals, silylenes, and sila-alkenes.In addition, small-ring silacycles of low stability are formed as the intermediates in some of the dehalogenation reactions.Combination and H-atom abstraction are the main reactions of silyl and silyl-methyl radicals.These radicals are not prone to decomposition reactions when C-H, C-C, or Si-C bonds are at the β(Si-Si) bond with the formation of Me2Si=CH2 and the trimethylsilyl radical.The generation of alkylmethylsilylenes is accompanied by their decomposition processes, which involves intramolecular β(C-H) insertion of alkylmethylsilylenes and 2+1>-thermocyclodecomposition of intermediate silacyclopropanes.The contribution of δ(C-H) and ε(C-H) insertion reactions is much less pronounced, and in the formation of five- or six-membered silacycles.We did not succeed in obtaining monosilacyclobutanes, as the intramolecular γ(C-H) insertion is not typical for silylenes with alkyl substituents.Dehalogenation of chloromethylchlorosilanes with alkali metal vapours yields sila-alkenes, and that of 1,2-dichlorodisilanes gives disilenes. 1-Methyl-1-silaethylene, obtained by this method, does not rearrange into dimethylsilene, but dimerizes to give 1,3-dimethyl-1,3-disilacyclobutane.The formation of 1,3,5-trisilacyclohexanes takes place due to subsequent radical addition at the silicon-carbon double bond and cyclization of 1,6-biradicals.Dehalogenation of organochlorosilanes XVI, XVII, and XX opens up possibilities for the gas-phase synthesis of small organosilicon heterocycles: monosilecyclobutanes and 1,2-disilacyclobutanes.A new, low-stability heterocycle, i.e. 1,1,2,2-tetramethyl-1,2-disilacyclobutane, has been obtained, which enables a new, high polymer, polyethylenetetramethyldisilene, to be obtained.In the case of organochlorosilanes XVIII and XIX, cyclization is accompanied by secondary reactions of silacycles, rearrangements, dimerization, or decomposition.
NOVEL 2,4-DISILATHIETANE RING SYSTEM FROM CYCLOADDITION OF 1,1-DIMETHYL-1-SILAETHYLENE, Me2Si=CH2, TO DIMETHYLSILANTHIONE, Me2Si=S. PERTURBATION MOLECULAR ORBITAL (PMO) STUDY ON REACTIVITY OF INTERMEDIATES WITH A DOUBLE-BONDED SILICON ATOM
Gusel'Nikov, L. E.,Volkova, V. V.,Avakyan, V. G.,Volnina, E. A.,Zaikin, V. G.,et al.
, p. 191 - 206 (2007/10/02)
Copyrolysis of 1,1-dimethyl-1-silacyclobutane (I) with both hexamethylcyclotrisilthiane (II) and tetramethylcyclodisilthiane (III) at 500 deg C involves 1,1-dimethyl-1-silaethylene, Me2Si=CH2 (IV), and dimethylsilanthione, Me2Si=S (V), intermediates and yields the following cycloaddition products: the new 2,2,4,4-tetramethyl-2,4-disilathietane (VI), 1,1,3,3-tetramethyl-1,3-disilacyclobutane (VII), and III.Six-membered cyclocarbosilthianes, 1,1,3,3,5,5-hexamethyl-2-thia-1,3,5-trisilacyclohexane (VIII) and 1,1,3,3,5,5-hexamethyl-2,4-dithia-1,3,5-trisilacyclohexane (IX) have also been derived by inserting IV and V into the Si-S bond of VI.Copyrolysis of I with thiethane (X) also results in four- and six-membered cyclocarbosilthianes, the major product being VI.This is discussed in terms of dimethylsilanthione formation via cycloaddition of IV to thioformaldehyde (XI) followed by 2 + 2>cyclodecomposition of the 2-silathiethane intermediate.A perturbation molecular orbital study of cycloaddition involving intermediates IV, V, and XI has shown that IV reacts more readily with V and XI than it cyclodimerizes.Dimerization of V is the most prominent reaction.
MERCURY-PHOTOSENSITIZED DECOMPOSITION OF HEXAMETHYLDISILANE.
Davidson,Potzinger,Reimann
, p. 13 - 19 (2007/10/02)
The kinetics and mechanism of the mercury-photosensitized decomposition of hexamethyldisilane have been studied. It has been confirmed that the initially-formed radical, Me//3SiSi(Me//2)CH//2, undergoes a unimolecular rearrangement; Arrhenius parameters have been measured for this rearrangement. The significance of these Arrhenius parameters in silicon chemistry is discussed by means of thermochemical calculations.
