- CYCLIC POLYSILANES. XIX. A TEMPERATURE STUDY OF REDISTRIBUTION EQUILIBRIA BETWEEN PERMETHYLCYCLOPOLYSILANES
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Equilibria among the cyclic compounds (Me2Si)n where n=5, 6 and 7 have been studied between 30-58 deg C.Thermodynamic values for the redistribution reactions between pairs of compounds are, for n=5 -> 6, ΔH=-18 kcal/mole, ΔS=-20 cal/deg. mole; for n=7 -> 6, ΔH -3, ΔS +33; for n=7 -> 5, ΔH +18, ΔS +51.The enthalpies indicate that the stabilities of the rings increase in the order (Me2Si)5 (Me2Si)7 (Me2Si)6.The differences are smaller than corresponding differences among the cycloalkanes, probably because the silicon compounds are less affected by steric repulsions and angle strain.
- Brough, Lawrence F.,West, Robert
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- Preparation and characterization of the inclusion complexes of poly(dimethylsilane)s with cyclodextrins
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β-Cyclodextrin (β-CD) and γ-cyclodextrin (γ-CD) formed inclusion complexes with poly-(dimethylsilane)s (PSi) of various molecular weights to give crystalline compounds. However, α-cyclodextrin (α-CD) did not form complexes with PSi of any molecular weight. The yelds of the γ-CD-PSi inclusion complexes decreased with increasing molecular weight of PSi. In contrast, the yields of the γ-CD-PSi inclusion complexes increased with increasing molecular weight, reached a maximum at molecular weight of around 760, and gradually decreased at higher molecular weight. The chain-length selectivities are totally different between β-CD and γ-CD. The γ-CD-PSi inclusion complexes are stoichiometric 1:3 (γ-cyclodextrin:monomer unit of PS) compounds. The complexes were isolated and characterized by 1H NMR, 13C CP/MAS NMR, and X-ray diffraction studies. These results suggest that CDs form channel-type complexes with PSi. The optical properties were studied by ultraviolet absorption and fluorescence spectroscopy. The PSi main chain in the cavities of γ-CD takes an all-trans conformation.
- Okumura, Hiromichi,Kawaguchi, Yoshinori,Harada, Akira
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- METHOD FOR PRODUCING CYCLIC POLYSILANE COMPOUND
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Provided is a method for producing a cyclic polysilane compound simply and easily in a higher yield. The method for producing a cyclic polysilane compound according to an embodiment of the present invention comprising a reaction step of adding a silane monomer compound represented by Formula (I) below into a liquid mixture containing metallic sodium and a lithium salt and allowing them to react: where, R1 and R2 each independently represent a hydrogen atom, a hydrocarbon group, an alkoxy group, or a halogen atom, X1 and X2 each independently represent a halogen atom or an alkoxy group, and ni is an integer that is greater than or equal to 1.
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Paragraph 0089-0109
(2021/09/10)
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- METHOD FOR PRODUCING CYCLIC POLYSILANE COMPOUND
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PROBLEM TO BE SOLVED: To provide a method for producing a cyclic polysilane compound from a silane monomer compound in one pot. SOLUTION: The present invention provides a method for producing a cyclic polysilane compound, including a first step of adding a silane monomer compound to a liquid mixture of a sodium dispersion and a solvent for a reaction, and a second step of adding an aromatic hydrocarbon to the reaction liquid obtained from the first step and heating and refluxing the mixture. SELECTED DRAWING: None COPYRIGHT: (C)2019,JPOandINPIT
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Paragraph 0073-0080
(2019/10/16)
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- METHOD FOR PRODUCING CYCLOHEXASILANE
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Provided is a method for efficiently obtaining cyclohexasilane using a cyclic silane dianion salt as a raw material without a by-product such as silane gas by a simple device. The method for producing cyclohexasilane has a feature that a cyclic silane dianion salt represented by the following general formula (i) or general formula (ii) is reacted with an aluminum-based reducing agent or a boron-based reducing agent: wherein X represents a halogen element, a represents an integer of 0 to 6, and R1 to R4 each independently represent a hydrogen atom, an alkyl group, or an aryl group; wherein X represents a halogen element, a represents an integer of 0 to 6, and R5 to R8 each independently represent a hydrogen atom, an alkyl group, or an aryl group.
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Page/Page column
(2014/02/15)
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- Compounds containing tetradecachlorocyclohexasilane dianion
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Compounds containing a tetradecachlorocyclohexasilane dianion are prepared by contacting trichlorosilane with a reagent composition comprising a tertiary polyamine. The compound ?pedeta.SiH2 Cl+1 !2 ?Si6 Cl14-2 ! wherein pedeta is N,N,N',N",N"-pentaethyldiethylenetriamine is prepared by contacting trichlorosilane with pedeta. The compound ?Ph4 P+1 !2 ?Si6 Cl14-2 ! is prepared by contacting trichlorosilane with a mixture of N,N,N',N'-tetraethylethylenediamine and triphenylphosphonium chloride. The tetradecachlorocyclohexasilane dianion can be chemically reduced to cyclohexasilane, a compound useful in the deposition of amorphous silicon films. The tetradecachlorcyclohexasilane dianion can also be contacted with a Grignard reagent to form a dodecaorganocyclohexasilane.
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- Synthesis of α,ω-dihalopermethyloligosilanes and silane-siloxane copolymers
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α,ω-Dibromopermethyloligosilanes, Br(SiMe2)nBr (n = 2-4, 6), were prepared by the reaction of dodecamethylcyclohexasilane with bromine. The reaction of (Me2Si)6 with MCl4 (M = Sn, Ti) proceeds with the cleavage of Si-Si-and Si-C-bonds with the formation of α,ω-dichloropermethyloligosilanes, Cl(SiMe2)nCI (n = 2-4, 6), and chloro derivatives of cyclohexasilane, ClmSi6Me12-m (m = 1, 2). Silane-siloxane copolymers of regular structure were obtained by heterofunctional copolycondensation of α,ω-dihalopermethyloligosilanes with 1,5-dihydroxyhexamethyltrisiloxane.
- Chernyavskii,Zavin
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p. 1449 - 1453
(2007/10/03)
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- Synthesis, properties and characterization of octadecamethylbicyclodecasilane
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The title compound 1 was obtained by Wurtz-type dehalogenative coupling of sym-dichlorotetramethyldisilane and trichloromethylsilane under appropriate conditions.Spectroscopic data for 1 are compared with those for bi(undecamethylcyclopentasilanyl) (2), a possible structural isomer.An X-ray structural study and 29Si-INEPT-INADEQUATE-NMR spectroscopy confirmed that only the trans-isomer of 1 is formed.Several attempts were made to obtain functional derivatives, but monocyclic and catenated oligosilanes were always obtained owing to breakdown of the bicyclic compound.Chemical and electrolytic reduction towards an anion radical was carried out at various temperatures.The ESR signal at 150 K shows an overlap of two distinct species: along with the spectrum of the well known Si5Me10(radical anion) that of a hitherto unknown species was observed.
- Jenkner, Peter K.,Hengge, Edwin,Czaputa, Rainer,Kratky, Christoph
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- Sonochemical synthesis of dodecamethylcyclohexasilane
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A comparative study of the kinetics of the reaction of dimethyldichlorosilane with metallic lithium under strong stirring or in the presence of ultrasonic vibrations in the cavitation regime has been carried out in order to demonstrate the special features of the reaction in the ultrasonic field and to obtain information on its mechanism.
- Los', G. P.,Zinov'ev, O. I.,Bashkirova, S. A.,Ivanov, V. I.,Lysova, G. V.,et al.
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p. 307 - 309
(2007/10/02)
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- Synthesis, 1H, 13C, and 29Si nuclear magnetic resonance spectra and crystal structure of trans-1,4-diphenyldecamethylcyclohexasilane
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The coupling reaction between PhMeSiCl2 and Me2SiCl2 in the presence of Na/K alloy resulted in a variety of phenylated permethylcyclohexasilanes of which only trans-1,4-Ph2Me10Si6 could be obtained in pure form by repeated recrystallizations.It was studied by means of nmr (1H, 13C, and 29Si) and X-ray crystallography.The crystals are monoclinic, P21/c with a = 10.105(6), b = 14.77(1), c = 9.973(6) Angstroem, β = 94.08(5) deg, V = 1485(2) Angstroem3, and Z = 2 for 1922 unique "observed" reflections and the structure refined to an R index of 0.036.The molecule has site symmetry 1 and the chair conformation of cyclohexane, with the two phenyl rings occupying the equatorial positions.
- Kumar, Kanta,Litt, Morton H.,Chadha, Raj K.,Drake, John E.
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p. 437 - 440
(2007/10/02)
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- γ-Induced Generation of Dimethylsilylene from Dodecamethylcyclohexasilane
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γ-Irradiation of dodecamethylcyclohexasilane (I) generates dimethylsilylene in 65percent yield when benzene is used as a solvent.Kinetic studies using anthracene as quencher are consistent with a mechanism proposed for the generation of dimethylsilylene, Benzene is first excited by γ-rays and energy is transferred to (I).Excited (I) decomposes to give dimethylsilylene presumably in a way similar to (I) excited by u.v. light.The ratio of the rate constant for self-deactivation of benzene to that for energy transfer from benzene to (I), k2/k3, is 5.1 x 1E-2 mol l-1 at room temperature.Energy transfer to (I) is hindered by added anthracene.The ratio of the rate constant for energy transfer to anthracene to that for energy transfer to (I), k6/k3, is ca. 6 at room temperature.A similar energy transfer is possible in the case of u.v. irradiation.
- Oka, Kunio,Nakao, Ren,Nagata, Yoshio,Dohmaru, Takaaki
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p. 337 - 340
(2007/10/02)
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- REACTIONS OF 1,2-DIMETHOXYTETRAMETHYLDISILANE WITH STYRENES: FORMATION OF A NEW TYPE OF SILACYCLOPENTANES HAVING PHENYL SUBSTITUENTS ON RING CARBONS
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The reaction of 1,2-dimethoxytetramethyldisilane with styrene and α-methylstyrene in the presence of NaOMe catalyst in tetrahydrofuran (THF) gave the new silacyclopentanes 1,1-dimethyl-2,4-diphenyl-1-silacyclopentane (IIIa) and 1,1,2,4-tetramethyl-2,4-diphenyl-1-silacyclopentane (IIIb), respectively.These silacyclopentanes were found to exist as cis-trans mixtures.The use of sodium metal in place of NaOMe afforded similar results.Reactions of a polysilane mixture, MeO(SiMe2)nOMe (n 3), with the styrenes also gave similar results.In some cases, polysilacycloalkanes such as 1,2,3-trisilacyclopentanes (IV) and 1,2,3,4-tetrasilacyclohexanes (V) were obtained as by-products.A mechanism for the formation of the silacyclopentanes and polysilacycloalkanes is presented.It was found that electron impact decomposition of silacyclopentanes IIIa and IIIb, trisilacycloalkane IV and tetrasilacycloalkane V gave molecular ions corresponding to the silacyclopropane, cyclotrisilane and cyclotetrasilane systems.
- Watanabe, Hamao,Inose, Jun,Muraoka, Tsutomu,Saito, Masayuki,Nagai, Yoichiro
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p. 329 - 342
(2007/10/02)
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- SYNTHESIS AND PROPERTIES OF SUBSTITUTED METHYLCYCLOPOLYSILANES
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Co-condensation of five equivalents Me2SiCl2 and one equivalent RR'SiCl2 with lithium provides the five- and six-membered rings RR'Si(Me2Si)4 and RR'Si(Me2Si)5.This method provides a direct route to the phenyl substituted methylcyclopolysilanes (R,R'=Me, Ph) which can be used for further functionalization of the silicon rings.It also provides several new sterically hindered methylcyclopolysilanes (R,R'=Ph, Ph; Me, t-Bu) which could not be synthesized by the conventional demethylation routes.These products have all been isolated and characterized by their ultraviolet, 1H-, 13C- and 29Si-NMR spectra.
- Helmer, Bradley J.,West, Robert
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- The Permethylcyclosilanes (Me2Si)5 through (Me2Si)35
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The cyclic permethylpolysilanes (Me2Si)n, where n = 5-35, are all formed when dimethyldichlorosilane (Me2SiCl2) is added slowly to sodium-potassium (Na/K) alloy in tetrahydrofuran (THF).NMR, UV, and vibrational spectra are reported for compounds n = 5-19.The 13C NMR and 1H NMR spectra are explained in terms of methyl-methyl group interactions.Raman and IR spectra are assigned and partially explained on the basis of a standing wave model.
- Brough, Lawrence F.,West, Robert
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p. 3049 - 3056
(2007/10/02)
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- ORGANIC SONOCHEMISTRY. ULTRASOUND PROMOTED COUPLING OF CHLOROSILANES IN THE PRESENCE OF LITHIUM WIRE
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Triorganometal chlorides, R3MCl (R=alkyl, aryl; M=Si, Sn) are readily coupled to form bimetallics in 42-95percent yields using Li wire and ultrasound.Dihalosilanes give good yields of cyclic polysilanes.
- Boudjouk, Philip,Han, Byung Hee
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p. 3813 - 3814
(2007/10/02)
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