- Isolable Silicon-Based Polycations with Lewis Superacidity
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Molecular silicon polycations of the types R2Si2+ and RSi3+ (R=H, organic groups) are elusive Lewis superacids and currently unknown in the condensed phase. Here, we report the synthesis of a series of isolable terpyridine-stabilized R2Si2+ and RSi3+ complexes, [R2Si(terpy)]2+ (R=Ph 12+; R2=C12H8 22+, (CH2)3 32+) and [RSi(terpy)]3+ (R=Ph 43+, cyclohexyl 53+, m-xylyl 63+), in form of their triflate salts. The stabilization of the latter is achieved through higher coordination and to the expense of reduced fluoride-ion affinities, but a significant level of Lewis superacidity is nonetheless retained as verified by theory and experiment. The complexes activate C(sp3)?F bonds, as showcased by stoichiometric fluoride abstraction from 1-fluoroadamantane (AdF) and the catalytic hydrodefluorination of AdF. The formation of the crystalline adducts [2(F)]+ and [5(H)]2+ documents in particular the high reactivity towards fluoride and hydride donors.
- Hermannsdorfer, André,Driess, Matthias
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- Nucleophilic fluorination of alkoxysilane with alkali metal hexafluorophosphate 1 - part 1
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Alkali metal hexafluorophosphates were used to effect nucleophilic fluorination of a few selected alkoxysilanes both in the presence and absence of polar solvents. Near-quantitative yields of fluorinated silanes were obtained using both alkoxy-equivalent of the complex salt and fluoride equivalents of alkoxysilanes. Some of the intermediate fluorosilanes and fluorophosphorus compounds were identified and the mechanism of fluorination is proposed.
- Farooq, Omar
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- METHOD FOR MANUFACTURING SILSESQUIOXANE COMPOUND
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Provided is a method for manufacturing a silsesquioxane compound represented by general formula (III) shown below, the method having a step of reacting a compound represented by general formula (I) shown below and a compound represented by general formula (II) shown below. In general formulas (I) to (III): each of R1 and R2 independently represents a hydrogen atom, an alkyl group of 1 to 8 carbon atoms, an aryl group of 6 to 14 carbon atoms, an aminoalkyl group, an amino group-containing group, a nitrile group-containing group, a vinyl group-containing group, a (meth)acryloyl group-containing group, a chloro group-containing group, a bromo group-containing group, or a functional group containing a boron trifluoride-complexed amino group, each of R3 to R10 independently represents an alkyl group of 1 to 8 carbon atoms or an aryl group of 6 to 14 carbon atoms, and M represents at least one element selected from the group consisting of hydrogen, lithium, sodium and potassium.
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Paragraph 0094-0095
(2021/03/05)
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- Synthesis method of diphenyl difluorosilane
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The invention discloses a synthesis method of diphenyl difluorosilane, belonging to the technical field of additives for battery electrolytes. The synthesis method comprises the following steps: withphenyldiethoxysilane as a raw material, adding phenyldiethoxysilane into a dry container; carrying out heating to 80-100 DEG C, and adding sodium trichloropyridinol and ethanol while stirring; then dropwise adding chlorobenzene into a mixture obtained in the previous step; after dropwise adding is finished, carrying out a reflux reaction for 3-8 hours, and conducting cooling to 30-35 DEG C; carrying out reduced-pressure suction filtration, adding sodium tetrafluoroborate into a filtrate, performing heating to 180-220 DEG C, and carrying out reacting for 4-6 hours; then conducting cooling to room temperature, performing diluting with dichloromethane, conducting quenching with water, and separating out an organic layer; and carrying out drying, carrying out vacuum concentration, and carryingout reduced-pressure distillation to obtain diphenyl difluorosilane. The synthesis method is simple, raw materials are cheap and easily available, reaction is stable, yield is high, and purity is high.
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Paragraph 0013-0023
(2020/11/23)
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- Synthesis of Double-Decker Silsesquioxanes from Substituted Difluorosilane
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A novel synthetic method for the construction of a double-decker silsesquioxane from fluorosilanes was developed. Phenyl-substituted double-decker silsesquioxane was prepared under mild conditions by coupling difluorodiphenylsilane and a tetrasiloxanolate precursor. A similar reaction was performed using difluorovinylsilane, and a divinyl double-decker silsesquioxane was obtained. The one-step reaction of a functional difluorosilane containing an aminopropyl group afforded a novel double-decker silsesquioxane with two amino groups complexed with BF3, which can react with carboxylic acid anhydrides to afford an amide product. This synthetic method using difluorosilane is tolerant of a wide range of functional groups and is applicable to the synthesis of polycyclic silsesquioxanes bearing amino groups, which are difficult to directly obtain from dichlorosilane.
- Tanaka, Toru,Hasegawa, Yasuharu,Kawamori, Takashi,Kunthom, Rungthip,Takeda, Nobuhiro,Unno, Masafumi
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supporting information
p. 743 - 747
(2019/03/04)
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- C?H and C?F Bond Activation Reactions of Fluorinated Propenes at Rhodium: Distinctive Reactivity of the Refrigerant HFO-1234yf
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The reaction of [Rh(H)(PEt3)3] (1) with the refrigerant HFO-1234yf (2,3,3,3-tetrafluoropropene) affords an efficient route to obtain [Rh(F)(PEt3)3] (3) by C?F bond activation. Catalytic hydrodefluorinations were achieved in the presence of the silane HSiPh3. In the presence of a fluorosilane, 3 provides a C?H bond activation followed by a 1,2-fluorine shift to produce [Rh{(E)-C(CF3)=CHF}(PEt3)3] (4). Similar rearrangements of HFO-1234yf were observed at [Rh(E)(PEt3)3] [E=Bpin (6), C7D7 (8), Me (9)]. The ability to favor C?H bond activation using 3 and fluorosilane is also demonstrated with 3,3,3-trifluoropropene. Studies are supported by DFT calculations.
- Talavera, Maria,von Hahmann, Cortney N.,Müller, Robert,Ahrens, Mike,Kaupp, Martin,Braun, Thomas
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supporting information
p. 10688 - 10692
(2019/07/10)
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- Synthesis and kinetics of disassembly for silyl-containing ethoxycarbonyls using fluoride ions
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In this study, a series of silyl-containing ethoxycarbonates and ethoxycarbamates on electron poor anilines and phenols were synthesized and their kinetics of disassembly determined in real-time upon exposure to fluoride ion sources at room temperature. The results provide a greater understanding of stability and kinetics for silyl-containing protecting groups that eliminate volatile molecules upon removal, which will allow for simplification of orthogonal protection in complex organic molecules.
- Camerino, Eugene,Daniels, Grant C.,Wynne, James H.,Iezzi, Erick B.
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p. 1884 - 1888
(2018/02/06)
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- Synthesis and applications of tert-alkoxysiloxane linkers in solid-phase chemistry
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Straightforward syntheses of two tert-alkoxysilyl chloride functionalised resins 3 and 31 that allow facile attachment of 1°, 2°, 3° alcohols and phenols to the solid-phase have been achieved. Resin 3 displayed useful loading levels (0.7 mmol/g), and it was stable to storage in activated form. Siloxanes from reaction of 3 with alcohols and phenols were compatible with a variety of reaction conditions commonly used in solid-phase synthesis.
- Meloni, Marco M.,White, Peter D.,Armour, Duncan,Brown, Richard C.D.
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p. 299 - 311
(2007/10/03)
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- Reaction of germanium tetrachloride with chloro(phenyl)silanes in the presence of aluminum chloride
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The effect of the quantity of aluminum chloride on the direction and depth of reaction of germanium tetrachloride with chloro(phenyl)silanes of the general formula PhnSiCl4-n (n = 1 - 3) was studied to show that radical exchange between germanium and silicon is initiated only if the mixture contains no less than 2.5-5 wt % of aluminum chloride. With trichloro(phenyl)silane, the radical exchange is initiated at 5 wt % of aluminum chloride and results in exclusive formation of trichloro(phenyl)germane. The reactions of GeCl4 with dichlorodiphenylsilane and chlorotriphenylsilane in the presence of 2.5-7.5 wt % of aluminum chloride give dichlorodiphenylgermane as the major product, and at AlCl3 concentrations of above 10 wt % the major product becomes to be trichloro(phenyl)germane.
- Zhun',Sbitneva,Chernyshev
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p. 867 - 869
(2007/10/03)
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- Process for producing fluorinated silicon compound
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There is disclosed a convenient and efficient process for producing a fluorinated silicon compound which comprises reacting a silicon compound having at least one group selected from the group consisting of a hydroxyl group, an alkoxy group, and an aryloxy group bonded to silicon atom, with a compound represented by the formula (1): wherein R1, R2, R3, and R4may be the same or different, and each represents a substituted or unsubstituted, saturated or unsaturated alkyl group, or a substituted or unsubstituted aryl group; and R1and R2or R3and R4can bond to form a ring having one or more nitrogen atoms or having one or more nitrogen atoms and other hetero atoms; or R1and R3can bond to form a ring having two or more nitrogen atoms or having two or more nitrogen atoms and other hetero atoms, to fluorinate the groups.
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Page column 9-10
(2008/06/13)
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- Silicon-based metalloprotease inhibitors: Synthesis and evaluation of silanol and silanediol peptide analogues as inhibitors of angiotensin-converting enzyme
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Silanols are best known as unstable precursors of siloxane (silicone) polymers, substances generally considered stable and inert, but have the potential to mimic a hydrated carbonyl and inhibit protease enzymes. While previous testing of simple silanediol and silanetriol species as inhibitors of hydrolase enzymes found them ineffective, this study reports polypeptide mimics with a central methylsilanol [SiMeOH] or silanediol [Si(OH)2] group and their assessment as effective transition state analogue inhibitors of the well-studied metalloprotease angiotensin-converting enzyme (ACE). Central to the synthesis strategy, phenylsilanes were employed as acid-hydrolyzable precursors of the silanol group. The N-benzoyl Leu-[SiMeOH]-Gly benzyl amides proved to be stable and readily characterized. In contrast, the Leu-[Si(OH)2]-Gly structure was difficult to characterize, possibly because of self-association. Capping the silanediols with chlorotrimethylsilane gave a well-defined trisiloxane, demonstrating that the silanediol was monomeric. The Leu-[Si]-Gly structures were converted to Leu-[Si]-Ala analogues by enolate alkylation. Coupling of the silanol precursors with proline tert-butyl ester gave N-benzoyl Leu-[Si]-Gly-Pro and N-benzoyl Leu-[Si]-Ala-Pro tripeptide analogues. Treatment of these with triflic acid formed the corresponding methylsilanols and silanediols, all of which were monomeric. The silanediol tripeptide mimics inhibited ACE with IC50 values as low as 14 nM. Methylsilanols, in contrast, were poor inhibitors, with IC50 values above 3000 nM. These data, including comparisons with inhibition data from carbon analogues, are consistent with binding of the silanediols by chelation of the ACE active site zinc, whereas the methylsilanols ligate poorly.
- Mutahi, Mwangi Wa,Nittoli, Thomas,Guo, Luxuan,Sieburth, Scott McN.
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p. 7363 - 7375
(2007/10/03)
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- Novel silyl linkers for solid-phase synthesis
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The syntheses of two silyl chloride resins, 2 and 10 are described starting from Merrifield resin, 3-methyl-1,3-butanediol and diphenyldichlorosilane or dimethyldichlorosilane, respectively. The silyl chloride resin 2 was used for the attachment of 1° alcohols, 2° alcohols and phenols to the solid phase. A preliminary study of the stability of the diphenylsiloxane linker towards certain reaction conditions was also carried out. A more reactive silyl chloride resin 10 was found to be suitable for the attachment of 3° alcohols to the solid phase.
- Meloni, Marco M.,Brown,White, Peter D.,Armour, Duncan
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p. 6023 - 6026
(2007/10/03)
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- Electronic effects and the stereochemistries in rearrangement-displacement reactions of triaryl(halomethyl)silanes with fluoride and with alkoxide ions
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Tetrabutylammonium fluoride (TBAF) reacts with (halomethyl)diphenyl(para-substituted-phenyl)silanes (13, X = Cl), 14 (X = Br), and 15 (X = I) in ether solvents to give fluorodiphenyl(parasubstituted-phenylmethyl)silanes (17a) and fluorophenyl(phenylmethyl)(para-substituted-phenyl)silanes (20a) by attack on silicon and migrations of the phenyl or the para-substituted-phenyl groups to C-1 with displacement of chloride ion. Sodium methoxide in dioxane effects rearrangement displacements of 14 (X = Br) to yield methoxydiphenyl(para-substituted-phenylmethyl)silanes (17b) and methoxyphenyl(phenylmethyl)(para-substituted-phenyl)silanes (20b). The migratory aptitudes of the varied phenyl groups in rearrangement-displacements of 13 with F- at 25°C are p-CF3-Ph, 2.72 > p-Cl-Ph, 1.67 > Ph, 1.00 > p-CH3-Ph, 0.91 > p-CH3O-Ph, 0.58 > p-(CH3)2N-Ph, 0.55. For reactions of 14 with sodium methoxide in dioxane, the migratory aptitudes at 23°C are p-CF3-Ph, 2.53 > p-Cl-Ph, 1.64 > Ph, 1.00 > p-CH3O-Ph, 0.84 > p-CH5-Ph, 0.79 > p-(CH3)2N-Ph, 0.68. The migratory aptitudes in the above rearrangement-displacements are increased by electron withdrawing substituents, and logarithms of the migratory aptitudes give satisfactory linear correlations with σ and/or σ-zero values of the phenyl substituents. Hammett correlations however of the migratory aptitudes from reactions of F- with 13 (X = Cl) at 0 and -20°C, 14 (X = Br) at 23, 0, and -20°C, and 15 (X = I) at 23°C are not linear. (+)-(Bromomethyl)methyl-1 naphthylphenylsilane (23, [α]D23 +8.29°, cyclohexane) reacts with CsF and with TBAF in THF to give benzylfluoromethyl-1-naphthylsilane (51, [α]D25 = 0.00°, cyclohexane) and fluoromethyl-(1 naphthylmethyl)phenylsilane (52, impure) in 10.4:1 ratio along with unchanged 23 ([α]D23 8.29°, cyclohexane). Sodium methoxide and (+)-23 in dioxane at 25°C and at 0°C yield (+)benzylmethoxymethyl-1-naphthylsilane (64) and (+)-methoxymethyl(1-naphthylmethyl)phenylsilane (65) in ~9:1 ratio. The conversions of (+)-23 to (+)-64 occur with 93% inversion about silicon. Reaction of (+)-23 with sodium methoxide at 25°C to give (+)-65 also occurs with inversion. Further, sodium ethoxide and sodium 2-propoxide react with (+)-23 at 20-25°C by rearrangement displacements on silicon with phenyl migrations to yield (+)-benzylethoxymethyl-1-naphthylsilane (69) and (+)-benzylmethyl-1-naphthyl-2-propoxysilane (70), respectively, each with 95% inversion about silicon. The mechanisms of rearrangement-displacements of 13-15 and (+)-23 by fluoride and by alkoxide ions are discussed.
- Allen, John M.,Aprahamian, Steve L.,Sans, Esther A.,Shechter, Harold
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p. 3561 - 3574
(2007/10/03)
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- Reaction of Organyltrifluorosilanes with Dimethylsulfoxide and Dimethylformamide and Its Spectroscopic Investigation
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Reaction of Organyltrifluorosilanes RSiF3 (R = C6H5, 3-02NC6H4, and C6H5CH2) with DMSO and DMF (B) results in formation of the complexes 2B*SiF4 and R2SiF2. Besides, biphenyl, benzene, methyl(fluoromethyl)sulfoxide, and S,S'-dimethyldisulfide-S,S'-dioxide
- Voronkov, M. G.,Boyarkina, E. V.,Gavrilova, G. A.,Basenko, S. V.
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p. 1865 - 1868
(2007/10/03)
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- Fluoridative degradation of cyclosiloxanes with alkali metal salts of perfluorinated complex anion. Part 5
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Alkali metal salts of perfluorinated 'non-nucleophilic' complex anions were used for fluoridative degradation of cyclosiloxanes under thermal conditions in the absence and presence of high boiling multifunctional etheral solvent. The degradative products
- Farooq, Omar
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p. 239 - 243
(2007/10/03)
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- Nucleophilic fluorination of alkoxysilane with alkali metal salts of perfluorinated complex anions. Part 2
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Alkali metal salts of perfluorinated complex anions have been used to effect nucleophilic fluorination of alkyl-, arylalkyl- and arylalkoxy-silanes both in the presence and absence of solvent. Near-quantitative yields of fluorinated silanes are obtained using equimolar quantities of fluoride ion equivalents and alkoxysilanes. In certain cases, intermediate organoboron and organophosphorus compounds derived from the corresponding complex anions and alkoxysilanes are identified in the reaction mixtures, and based on these intermediates a mechanism of reaction has been proposed.
- Farooq, Omar
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p. 661 - 665
(2007/10/03)
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- Rate increases in the fluorination of bulky chlorosilanes caused by ultrasound or by water
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The conversion of bulky chlorosilanes to fluorosilanes under anhydrous conditions with hexafluorosilicate salts is accelerated by ultrasound. The fluorination of sterically hindered chlorosilanes such as tBuPh2SiCl, in the absence of ultrasound, is greatly accelerated by the addition of water to the reaction mixture.
- Lickiss, Paul D.,Lucas, Ronan
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p. 167 - 172
(2007/10/03)
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- Anion complexation by bidentate Lewis acidic hosts, ortho-bis(fluorosilyl) benzenes
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Ortho-bis(fluorosilyl)benzenes, precursors for bis-siliconates, o-C6H4(SiPhF2)2 (1), o-C6H4(SiF3)(SiPh2F) (2) and o-C6H4(SiPhF2)(SiPh2F) (3), possess anion binding properties as bidentate Lewis acidic hosts in organic solvents. Compound 1 quantitatively binds a fluoride ion from KF suspended in acetone or tetrahydrofuran without support of 18-crown-6 to form the corresponding soluble bis-siliconate [o-C6H4(SiPhF2)2F]K (4). The binding constants of a series of fluorosilanes for a fluoride ion are measured by 1H and 19F NMR spectroscopies. The affinity of fluorosilanes towards a fluoride ion increases in the order PhMeSiF2 (7) 2SiF2 (9) 1.1 × 109 M-1 at 193 K. These bidentate Lewis acids 1-3 are among the strongest organic hosts for a fluoride ion in organic solvents ever reported.
- Tamao, Kohei,Hayashi, Takashi,Ito, Yoshihiko
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- Alkali Metal Salts of Perfluorinated Complex Anions. Effective Reagents for Nucleophilic Fluorination
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Alkali metal salts of perfluorinated complex anions were used to effect halogen-exchange fluorination in organohalosilanes both in the presence and absence of solvent.By the use of salts of perfluorinated "non-nucleophilic" anions in a high-boiling multifunctional etheral solvent, organofluorosilanes have been conveniently prepared in high yields.
- Farooq, Omar,Tiers, George V. D.
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p. 2122 - 2124
(2007/10/02)
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- ELECTRONIC EFFECTS AND MECHANISTIC FEATURES IN THE REARRANGEMENT-DISPLACEMENT REACTIONS OF ARYL(CHLOROMETHYL)DIPHENYLSILANES WITH FLUORIDE ION
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At 25 deg C aryl migrations from negatively-charged pentacoordinate silicon correlate with the abilities of the rearranging groups to bear negative charge, but at lower temperatures the migrations become less dependent on electron-withdrawing stabilization.
- Aprahamian, Steve L.,Shechter, Harold
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p. 1089 - 1092
(2007/10/02)
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- DARSTELLUNG UND CHARAKTERISIERUNG DER PHENYLFLUORDISILANE Si2Ph6-nFn
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Fluorination of chlorophenyldisilanes with ZnF2 yields the corresponding fluorophenyldisilanes, if silver powder is used as a catalyst. 1,2-Difluorotetraphenyldisilane is synthesized by UV irradiation of bis-(fluorodiphenylsilyl)mercury, the first known fluorosilylmercury compound.All the eight possible fluorophenyldisilanes, unknown up to now, are characterized by spectroscopic methods.
- Hengge, E.,Schrank, F.
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- USE OF SbF5 INTERCALATED IN GRAPHITE AS FLUORINATING REAGENT IN ORGANO-SILICON AND -GERMANIUM CHEMISTRY
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The use of SbF5 intercalated in graphite as fluorinating reagent of organo-silicon and -germanium derivatives is described.While Si-O and Si-Cl bonds are readily cleaved, Si-H and Si-S bonds are only reactive in bifunctional silanes.Ge-X bonds (X=Br, Cl, OR, H) are unreactive.Allyl-silicon and allyl-germanium bonds are broken under mild conditions and in high yields, leading to the corresponding fluorosilane or fluorogermane.With bifunctional silanes, it is always possible to obtain the difluorinated derivatives.
- Corriu, R.J.P.,Fernandez, J.M.,Guerin, C.
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p. 347 - 352
(2007/10/02)
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