- Improved synthetic route to potassium silyl using crown ethers, potassium, and silane and its use to prepare methylsilane and disilylmethane
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The time for the reaction between K and SiH4 in glyme is reduced from months to hours by addition of 18-crown-6 to form SiH3.The usefulness of the reaction to prepare the SiH3- anion as a synthetic intermediate is demonstrated by the reaction of SiH3 with CH3I and CH2Cl2 to prepare H3SiCH3 and (H3Si)2CH2, respectively.The rate of the reactions between K and GeH4 is also increased but not as dramatically with the addition of 18-crown-6 to form GeH3.
- Fieselmann, Benjamin F.,Dickson, C. Robert
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- CATALYST DEHYDROGENATIVE COUPLING OF CARBOSILANES WITH AMMONIA, AMNINES AND AMIDINES
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Si-containing film forming compositions are disclosed comprising Si-N containing precursors. Also disclosed are methods of synthesizing the same and methods of using the same for vapor deposition. In particular, a catalytic dehydrogenative coupling of carbosilanes with ammonia, amines and amidines produces the Si-N containing precursors.
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Paragraph 00116; 00118
(2016/10/27)
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- Reaction of Hydrogen Peroxide with Organosilanes under Chemical Vapour Deposition Conditions
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When a stream of vapour at low pressure which contained a mixture of H2O2 with an organosilane, RSiH3 (R = alkyl or alkenyl), impinged on a silicon wafer, deposition of oxide films of nominal composition RxSiO(2-0.5x), where x 3 or higher alkenyl groups. or higher alkenylgroups. Possible mechanism for the Si-C bond cleavage reaction are discussed, with energetic rearrangement of radical intermediates of type Si(H)(R)(OOH)' being favoured.
- Moore, Darren L.,Taylor, Mark P.,Timms, Peter L.
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p. 2673 - 2678
(2007/10/03)
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- Poly(trifluoromethanesulfonatosilyl)methanes - Precursors to Polysilylmethanes
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A new an efficient synthetic route to di- and tri(silyl)methane is presented.Starting from bis- and tris(phenylsilyl)methane, bis- and tris(trifluoromethanesulfonatosilyl)methane can be obtained by Si-Ph cleavage with equivalent quantities of trifluoromethanesulfonic acid (triflic acid).Their reduction with lithium aluminium hydride yields di- and tri(silyl)methane.Substitution of the previously employed liquid anhydrous hydrogen bromide by triflic acid thus offers an experimentally more simple alternative with shorter reaction times and high selectivity. - Keywords: Poly(silyl)methanes, Silanes, Trifluoromethanesulfonates
- Bommers, Sebastian,Schmidbaur, Hubert
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p. 337 - 339
(2007/10/02)
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- Synthetic Pathways to Disilylmethane, H3SiCH2SiH3 and Methyldisilane, CH3SiH2SiH3
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Disilylmethane is available in a four-step synthesis starting with phenylsilane.This is converted into chlorophenylsilane by HCl/AlCl3.The reaction of PhSiH2Cl and bibromomethane with magnesium in tetrahydrofuran affords bis(phenylsilyl)methane, which yields bis(bromosilyl)methane by treatment with anhydrous hydrogen bromide. (BrH2Si)2CH2 is converted into disilylmethane by reduction with LiAlH4 in a two-phase system using a phase-transfer catalyst. - Methyldisilane is available by alkylation of monohalodisilane, XSi2H5 (X=Cr, Br), with methyllithium in a high-boiling ether or by silylation of bromomethylsilane with silylpotassium.Due to secondary silylation reactions the overall yields of methyldisilane are low in all cases.
- Zech, Joachim,Schmidbaur, Hubert
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p. 2087 - 2091
(2007/10/02)
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- A Synthetic Route to Poly(silyl)methanes via Poly(phenylsilyl)methanes and Poly(bromosilyl)methanes
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A three-step synthesis is presented for di- and tri(silyl)methane, two feedstock gases for the chemical vapour deposition of amorphous hydrogenated silicon/carbon alloys (a-SiC:H).Chloro(phenyl)silane and di-or trihalomethanes react with magnesium in tetrahydrofuran to give high yields of bis- and tris(phenylsilyl)methane, respectively.The two products can be converted into bis- and tris(bromosilyl)methane by treatment with anhydrous hydrogen bromide.Bromide/hydride substitution in these precursors is accomplished with lithium aluminum hydride in a two phase system using a phase-transfer catalyst.The compounds CH2(SiH2Ph)2, CH(SiH2Ph)3, CH2(SiH2Br)2, CH(SiH2Br)3, CH2(SiH3)2, and CH(SiH3)3 have been characterized by standard spectroscopic methods, and the crystal and molecular structure of CH(SiH2Ph)3 has been determined by single-crystal X-ray diffraction.The molecule adopts a conformation with crystallographic C3 symmetry.This result is discussed with regard to the structure of related molecules with three substituents of potential Cs symmetry at a tetrahedral center. - Key Words: CVD feedstock gases / Poly(bromosilyl)methanes / Poly(phenylsilyl)methanes / Poly(silyl)methanes / Silanes
- Hager, Rudolf,Steigelmann, Oliver,Mueller, Gerhard,Schmidbaur, Hubert
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p. 2115 - 2120
(2007/10/02)
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- Process for preparing disilylmethanes
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The present invention relates to a process for preparing disilylmethanes, wherein the magnesian reaction is carried out between methylene chloride and at least one chlorosilane in a donor solvent.
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- Synthetic Pathways to Simple Di- and Trisilylmethanes: Potential Starting Materials for the CVD Deposition of Amorphous Silicon a-SiC:H
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Methods for the preparation of simple silaalkanes with a high content of silicon and hydrogen have been explored.Target molecules, like H3SiCH2SiH3 and HC(SiH3)3, may serve as precursor molecules for the production of photovoltaic elements through thermal or discharge (plasma) CVD processes.Among a variety of synthetic pathways, the reactions between HSiCl3 and HCCl3 in the presence of an amine (Benkeser reaction) and the direct synthesis from silicon and polychloromethanes proved most promising for large scale preparations.The CH2X2/KSiH3 metathesis is most useful on the laboratory scale. - The Grignard synthesis was employed for partly methylated homologues, like H3SiCH2SiH2CH3, H3SiCH2SiH(CH3)2, H3SiCH2Si(CH3)3, and related molecules.The magnesium reduction of CHBr3/SiCl4 and CHBr3/CH3SiCl3 mixtures serves best for the preparation of HC(SiCl3)3, which can be converted into HC(SiH3)3 using LiAlH4.Attempts to synthesize tetrasilylmethane via the same route, C(SiH3)4, led only to the formation of HC(SiH3)3. - Key words: Amorphous Silicon a-SiC:H, Disilylmethane, Trisilylmethane, Direct Synthesis, Polysilylmethanes
- Schmidbaur, Hubert,Ebenhoech, Jan
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p. 1527 - 1534
(2007/10/02)
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