- CHEMISTRY OF ALKALI METAL-UNSATURATED HYDROCARBON ADDUCTS. XI. ESR MONITORING OF TRANSIENT RADICAL-ANIONS FROM UNSATURATED ORGANOSILANES
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By the potassium-metal reduction of a series of α,β-unsaturated organosilanes at low temperatures, radical-anionic intermediates were generated.Both the detailed structure of such radical-anions and their chemical transformations were studied by a combination of ESR spectroscopy and chemical characterization.Relatively stable radical-anions were obtained from the methyl(phenyl)silanes, tetraphenylsilane and hexaphenyldisilane, but even these decomposed eventually through cleavage and coupling processes.More labile radical-anions arose from organosilanes of the type, Ph3SiE, where E was chloro, cyclopropyl, substituted biphenyl, vinyl, 1-propenyl and 1-propynyl.In several cases, the transient parent radical-anion could be measured with ESR spectroscopy by working at low temperatures in the presence of HMPT.As an aid to deciding among several possible structural assignments of an ESR spectrum, the actual chemical products obtained from such reductions were scrutinized.The conclusion reached from these studies is that that part of the organosilane molecule bearing the highest free electron spin density in the radical-anion is the site of highest chemical reactivity.Sites of radical-coupling, chemical reduction, isomerization and carbon-silicon bond cleavage can be predicted from such ESR data.
- Eisch, John J.,Smith, Leslie E.
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Read Online
- Disilane and preparation method thereof
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The invention discloses disilane and a preparation method thereof. The preparation method of disilane includes: subjecting a uniformly mixed reaction system containing tertiary hydrosilane and a catalyst to dehydrogenation reaction at a temperature ranging from -10DEG C to 120DEG C to obtain disilane, wherein the catalyst comprises a silver salt. The invention also discloses the disilane preparedby the method. The method for preparation of the disilane by catalyzing tertiary silane dehydrogenation with the silver salt adopts the silver salt to activate the Si-H bond in the silane so as to realize construction of disilane. Therefore, the invention provides an efficient and simple method for preparation of the compound, and the application prospect is wide.
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Paragraph 0039; 0043-0045
(2020/01/25)
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- Proximity enforced oxidative addition of a strong unpolar σ-Si-Si bond at rhodium(i)
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The new bidentate bisphosphino ligand (5-Ph2P-Ace-6-SiMe2)2 (1) binds rhodium(i) chloride and brings it into close proximity to a strong unpolar σ-Si-Si bond, in which it immediately inserts. In the spirocyclic Rh(iii) product of the oxidative addition, (5-Ph2P-Ace-6-SiMe2)2RhCl (2), the two Si atoms are still close enough to engage in weak non-covalent interactions.
- Beckmann, Jens,Holsten, Sebastian,Hupf, Emanuel,Lork, Enno,Mebs, Stefan
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supporting information
p. 1731 - 1735
(2020/02/21)
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- METHOD FOR PRODUCING SILYL SODIUM COMPOUND AND METHOD FOR DEOXIDIZING EPOXY COMPOUND
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PROBLEM TO BE SOLVED: To construct a technique which can simply, efficiently and inexpensively synthesize a silyl sodium compound in a small number of processes and in a short time, especially to construct a technique which synthesizes a silyl sodium compound by using easily available reagents from a viewpoint of sustainability without using reagents which are difficult to handle and are toxic. SOLUTION: There is provided a method for synthesizing a silyl sodium compound comprising a step of reacting a dispersion obtained by dispersing a silyl halide compound or a disilane compound with sodium into a dispersion solvent, the silyl halide compound or the disilane compound as a starting compound, in a reaction solvent to obtain the silyl sodium compound. There is also provided a method for deoxidizing an epoxy compound comprising a step of reacting the silyl sodium compound obtained by synthesizing method of the silyl sodium compound with an epoxy compound to deoxidize the epoxy compound to stereoselectively produce an alkene compound. SELECTED DRAWING: Figure 1 COPYRIGHT: (C)2020,JPOandINPIT
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Paragraph 0087-0089
(2020/05/06)
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- Method for continuously preparing disilane compounds by micro-reaction device
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The invention discloses a method for continuously preparing disilane compounds by a micro-reaction device. The method comprises the following steps: (1) a solution A is prepared from organosilane by dissolving in a first organic solvent, or is organosilane; (2) a solution B is prepared from an oxidant by dissolving in a second organic solvent, or is an oxidant; (3) the solution A and the solutionB are pumped into a micro-mixer of the micro-reaction device simultaneously for mixing, a product then flows into a microreactor of the micro-reaction device for reaction, and the disilane compounds are prepared, wherein the microreactor is filled with a catalyst. Raw materials required in the method are easily available and have better stability, metal copper compounds are used as a catalyst forcoupling reaction on trisubstituted silanes, and the coupling effect on trisubstituted silanes is better than that of alkali metal catalysts and transition metal catalysts; a micro-channel reactor issuitable for an exothermic coupling reaction due to good mixing and heat transfer performance.
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Paragraph 0025; 0026; 0031; 0032
(2018/05/16)
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- Reactions of molybdenum hydrides with organochlorosilanes: Silicon-silicon bond formation under mild conditions
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Reactions of molybdenum hydrides containing polydentate phosphinoalkylsilyl ligands with a number of chlorosilanes have been investigated; this has led to the discovery of a novel type of a dechlorinative Si-Si coupling reaction.
- Asaeda, Takahiro,Lee, Joo Yeon,Watanabe, Kyosuke,Minato, Makoto
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p. 1005 - 1007
(2014/07/22)
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- PREPARATION OF SI-SI BOND-BEARING COMPOUNDS
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Si—Si bond-bearing compounds are effectively prepared by irradiating with radiation or heating Si—H group-bearing silicon compounds in organic solvents in the presence of iron complex catalysts. The Si—Si bond-bearing compounds are useful as a base material in photoresist compositions, ceramic precursor compositions, and conductive compositions.
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Page/Page column 3
(2009/05/28)
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- Direct construction of silicon-silicon bond by using the low-valent titanium reagent
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The reductive dimerization or polymerization of organochlorosilanes has been achieved by using the low-valent titanium reducing agent other than the alkali metals that are invariable used in the Wurtz-type coupling reaction. Applying this method, the corresponding disilanes or poly(methylvinylsilane) was obtained in good yields. The poly(methylvinylsilane) synthesized by this method is highly pure with a high molecular weight and a narrow molecular weight distribution (Mw/Mn = 1.6, Mn = 16,860).
- Lai, Guoqiao,Li, Zhifang,Huang, Jiabang,Jiang, Jianxiong,Qiu, Huayu,Shen, Yongjia
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p. 3559 - 3562
(2008/02/12)
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- Carbanion mechanisms XXI. Solution acidity of triphenylsilane
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Comparative acidity measurements have been performed between triphenylsilylpotassium and a series of arylmethanes by 1H-NMR in tetrahydrofuran: Ph3SiK + ArnCH4 - n ? Ph3SiH + ArnCH3 - nK Metalation of the arylmethane was complete in the case of Ph3CH (pKa 31.4) and Ph2CH2 (pKa 33.4) but with (p-CH3·C6H4)2CH2 (pKa 35.1) ~50% metalation of the di-p-tolymethane occurred, indicating that the two acids have equal pKa. No reaction occurred with 4-Ph·C6H4·CH3 (pKa 38.7). Thus pKa Ph3SiH ≈ 35.1 in THF. This represents the first solution measurement of the acidity of an organosilane.
- Buncel, Erwin,Venkatachalam
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p. 208 - 210
(2007/10/03)
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- Electroreductive Synthesis of Polysilanes, Polygermanes, and Related Polymers with Magnesium Electrodes
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The electroreduction of alkylaryldichlorosilane carried out with Mg cathode and anode in a single compartment cell gave high molecular weight poly(alkylarylsilane) (Mn = 5200-31000, Mw/Mn = 1.4-1.8) in 5-79% yield. The effects of electrode material, monomer concentration, amount of supplied electricity, and ultrasound were investigated. This electroreductive method was also successfully applied to the synthesis of polygermanes, silane-geramane copolymers, and also poly[p-(disilanylene)phenylenes].
- Kashimura, Shigenori,Ishifune, Manabu,Yamashita, Natsuki,Bu, Hang-Bom,Takebayashi, Masakatsu,Kitajima, Satsuki,Yoshiwara, Daisuke,Kataoka, Yasuki,Nishida, Ryoichi,Kawasaki, Shin-Ichi,Murase, Hiroaki,Shono, Tatsuya
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p. 6615 - 6621
(2007/10/03)
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- Method for producing disilanes
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A method for producing disilane characterized in that halosilane is subjected to electrochemical reaction using Al, Al alloy, Mg, Mg alloy, Cu, Cu alloy, Zn or Zn alloy as anode, a lithium salt as supporting electrolyte, an Al salt, Fe salt, Mg salt, Zn salt, Sn salt, Co salt, Pd salt, V salt, Cu salt, Ca salt, Na salt or K salt as current carrying aid, and an aprotic solvent as solvent, thereby producing disilane.
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- Oligosiloles: First synthesis based on a novel endo-endo mode intramolecular reductive cyclization of diethynylsilanes
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A general and versatile synthesis of 2,5-difunctional siloles and their conversion into oligosiloles are described. Diethynylsilanes undergo intramolecular reductive cyclization in an endo-endo mode upon treatment with lithium naphthalenide to form 2,5-dilithiosiloles. The 2,5-dilithiosiloles are converted into various 2,5-difunctional siloles by treatment with electrophiles. The resulting 2,5-dibromosilole is further converted into several highly functionalized siloles via palladium-catalyzed cross-coupling reaction or selective mono-lithiation using n-butyllithium in ether. Oligosiloles, from bisiloles to quatersilole, are prepared from certain functional siloles. Oxidative coupling of 2,5-dilithiosilole by use of an Fe(III) complex affords 2,2′-bisilole as yellow crystals. Difunctional oligosiloles, 5,5′-dibromo-2,2′-bisilole and 5,5?-dibromo-2,2′:5′,2″:5″,2? -quatersilole, are prepared by oxidative coupling via higher order cyanocuprate of 2-bromo-5-lithiosilole and 5-bromo-5′-lithio-2,2′-bisilole, respectively. X-ray crystal structures of these bisiloles show highly twisted arrangements between two silole rings with 62-64° of torsion angle. 1H NMR studies on bisiloles show a rapid equilibration between non-coplanar conformers in solution. In UV-visible spectra, nevertheless, all of the oligosiloles have unusually long absorption maxima.
- Tamao, Kohei,Yamaguchi, Shigehiro,Shiro, Motoo
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p. 11715 - 11722
(2007/10/02)
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- Electroreductive Formation of Polysilanes
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Electroreduction of dichlorosilanes, such as 1,1-dichlorodialkylsilanes, 1,2-dichlorotetra-alkyldisilanes, and 1,4-bis(chlorodialkylsilyl)benzenes, with Mg electrodes in a single-compartment cell was found to yield the corresponding polysilanes.
- Shono, Tatsuya,Kashimura, Shigenori,Ishifune, Manabu,Nishida, Ryoichi
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p. 1160 - 1161
(2007/10/02)
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- Efficient formation and cleavage of disilanes by potassium-graphite. Silylation with silyl metal reagents
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Potassium-graphite laminate (C8K) very rapidly forms disilanes from chlorosilanes and then rapidly cleaves the disilanes to give silyl potassium reagents which can be converted into potassium silyl cuprates, -manganates, and -vanadates that are useful for various nucleophilic substitution and addition reactions.
- Fuerstner, Alois,Weidmann, Hans
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- Les triorganosilylpotasium: nouvelle voie d'acces et quelques aspects de leur reactivite
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We report here a new procedure for the convenient and easy preparation of silylanions and especially of Me3Si-.These undergo coupling reaction with halides and α-enone in good yields.Reactions with 5-bromo-1 hexene, benzophenone and carbon dioxide provide evidence for the ability of the silylpotassium to act as monoelectron transfer reagents.The course of these reactions varies substantially with the nature of the solvent.
- Corriu, R. J. P .,Guerin, C.,Kolani, B.
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p. 973 - 979
(2007/10/02)
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- METHYLPHENYLTRIPHENYLGERMYLSILANES FONCTIONNELS OPTIQUEMENT ACTIFS
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The structure of the unsymmetric compound MePh(X)SiGePh3 (X=H, F, Cl, OR) has been resolved.The stereochemistry of nucleophilic substitutions at silicon is not changed with Ph3Ge as substituent.Stereochemical correlations allow the determination of absolute configurations.
- Corriu, R. J. P.,Ould-Kada, S.,Lanneau, G.
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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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- AN ELECTROCHEMICAL METHOD FOR THE SYNTHESIS OF SILICON-SILICON BONDS
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An electrochemical method for the preparation of compounds containing Si-Si bonds has been developed and its scope investigated.
- Hengge, E.,Firgo, H.
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p. 155 - 161
(2007/10/02)
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- ELECTROCHEMICAL REDUCTION OF TRIORGANOHALO-SILANES AND -GERMANES
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The electrochemical reduction of triorganohalo-silanes and -germanes in 1,2-dimethoxyethane has been investigated by polarography, cyclic voltammetry, controlled potential coulometry, and macroscale electrolysis.The reduction of the silicon compounds exhibits a single irreversible wave.The polarograms for the germanium compounds exhibit two irreversible waves.The second wave shifts to more anodic potentials with addition of phenol or acetic acid.Dimer (i.e. disilanes or digermanes) are the main product of macroscale electrolysis in aprotic solvent but the hydrides are the principal products in protic solution.The results are interpreted in terms of the coexistence of two separate processes.The first involves a one electron reduction followed by dimerization of the radical.At higher cathodic potential a two electron charge transfer step occurs to form an anion, which in aprotic solvents reacts with the starting halogeno compound to form dimer, and in protic solutions gives the hydride.
- Corriu, R. J. P.,Dabosi, G.,Martineau, M.
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