- An Electroreductive Approach to Radical Silylation via the Activation of Strong Si-Cl Bond
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The construction of C(sp3)-Si bonds is important in synthetic, medicinal, and materials chemistry. In this context, reactions mediated by silyl radicals have become increasingly attractive but methods for accessing these intermediates remain limited. We present a new strategy for silyl radical generation via electroreduction of readily available chlorosilanes. At highly biased potentials, electrochemistry grants access to silyl radicals through energetically uphill reductive cleavage of strong Si-Cl bonds. This strategy proved to be general in various alkene silylation reactions including disilylation, hydrosilylation, and allylic silylation under simple and transition-metal-free conditions.
- Lu, Lingxiang,Siu, Juno C.,Lai, Yihuan,Lin, Song
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supporting information
p. 21272 - 21278
(2020/12/21)
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- Silane bridging luminescent material, preparation method and application thereof, and color developing agent
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The invention relates to the technical field of detection, and discloses a silane bridging luminescent material, a preparation method and an application thereof, and a color developing agent, the silane bridging luminescent material has a structure repres
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Paragraph 0067; 0071-0073
(2020/07/13)
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- Conductive molecular silicon
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Bulk silicon, the bedrock of information technology, consists of the deceptively simple electronic structure of just Si-Si σ bonds. Diamond has the same lattice structure as silicon, yet the two materials have dramatically different electronic properties. Here we report the specific synthesis and electrical characterization of a class of molecules, oligosilanes, that contain strongly interacting Si-Si σ bonds, the essential components of the bulk semiconductor. We used the scanning tunneling microscope-based break-junction technique to compare the single-molecule conductance of these oligosilanes to those of alkanes. We found that the molecular conductance decreases exponentially with increasing chain length with a decay constant β = 0.27 ± 0.01 A-1, comparable to that of a conjugated chain of C = C π bonds. This result demonstrates the profound implications of σ conjugation for the conductivity of silicon.
- Klausen, Rebekka S.,Widawsky, Jonathan R.,Steigerwald, Michael L.,Venkataraman, Latha,Nuckolls, Colin
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supporting information; experimental part
p. 4541 - 4544
(2012/04/23)
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- Synthesis and characterisation of two new binaphthyl trisilanes
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The synthesis and characterisation of two binaphthyl trisilanes is described. Reaction between 2,2′-dilithio-1,1′-binaphthyl and 1,3-dichlorohexamethyltrisilane gave 3,3,4,4,5,5-hexamethyl-4,5-dihydro-3H-3,4,5-trisilacyclohepta[2,1-a;4,3-a′]binaphthalene
- Russell, Alexander G.,Guveli, Tatyana,Kariuki, Benson M.,Snaith, John S.
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experimental part
p. 137 - 141
(2009/04/10)
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- Polymeric organosilicon systems. XXIX. Thermal properties of poly[(disilanylene)oligophenylenes]
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Thermal properties of variously substituted poly[(disilanylene)oligophenylenes], [(SiR1R2SiR1R2)(p-C6H4)m]n (R1=R2=Me, R1=R2=Et, and R1=Ph, R2=Me, m=1-4) were investigated. The thermogravimetric analysis of the polymers in the range of 20-1000°C showed rapid weight loss starting from about 400°C. The total weight loss of the polymers at 1000°C was calculated to be 54.5-75.5% based on the initial weight of the polymers. GC-MS analysis of the volatile products obtained from the pyrolysis of the polymers with R1=R2=Me, m=2 and R1=R2=Et, m=1-4 at 500°C indicated the formation of silicon-containing oligomers arising from the Si-Si and Si-phenylene bond cleavage, mainly. The formation of oligophenylenes, H(C6H4)lH (l=1-4), was also observed in the pyrolysis of the polymers with m=3 and 4. A model reaction for the polymer degradation was also examined, using 1,2-diphenyltetramethyldisilane.
- Ohshita, Joji,Sugimoto, Kazunori,Watanabe, Tsuguo,Kunai, Atsutaka,Ishikawa, Mitsuo,Aoyama, Susumu
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- The preparation and analysis of the phenyldimethylsilyllithium reagent and its reaction with silyl enol ethers
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Phenyldimethylsilyllithium is formed from lithium and phenyldimethylsilyl chloride by slow cleavage of the Si-Si bond of 1,1,2,2-tetramethyl-1,2-diphenyldisilane after the rapid formation of the disilane. 1,1,2,2-Tetramethyl-1,2-diphenyldisiloxane, produced from the silyl chloride by reaction with oxides and hydroxides on the lithium metal surface, is cleaved by dimethyl(phenyl)silyllithium to give lithium dimethyl(phenyl)silanoxide. Dimethyl(phenyl)silyllithium reacts with 1,2-dibromoethane to give dimethyl(phenyl)silyl bromide, which is so rapidly consumed by excess silyllithium reagent that it does not interfere with the double titration used to measure its concentration. Dimethyl(phenyl)silane, produced by protonation of the silyllithium reagent, is also consumed by the silyllithium reagent to give 1,1,2,2-tetramethyl-1,2-diphenyldisilane, which regenerates the silyllithium reagent, as long as lithium is still present. By-products in the preparation of dimethyl(phenyl)silyllithium include 1,3-diphenyl-1,1,2,2,3,3-hexamethyltrisilane, dimethyldiphenylsilane and 1,4-bis[dimethyl(phenyl)-silyl]benzene. Dimethyl(phenyl)silyllithium displaces the silyl group from the tert-butyldimethylsilyl enol ether of cyclohexanone to give the lithium enolate under relatively mild conditions.
- Fleming, Ian,Roberts, Richard S.,Smith, Stephen C.
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p. 1209 - 1214
(2007/10/03)
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- Synthese, Kernresonanzspektren und Schwingungsspektren der Hexamethyltrisilane und Pentamethyltrisilane (XMe2Si)2SiMe2 und (XMe2Si)2SiMeX (X=H, F, Cl, Br, I, Ph, OMe)
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The syntheses, IR, Raman and 29Si spectra of the title compounds are reported.SiSi force constants, calculated with the aid of normal coordinate analyses, are compared with 29Si29Si coupling constants.
- Schenzel, Karla,Hassler, Karl
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p. 127 - 138
(2007/10/02)
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- Dearylation of α,ω-diphenylpermethylated oligosilanes with triflic acid
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The relative rates of displacement of phenyl groups for a series of α,ω-diphenylpermethylated oligosilanes with the formula Ph(SiMe2)nPh (n = 2-5) were studied.Triflic acid was utilized in the displacement reactions which occur as a two-step process with protonation at the ipso-carbon atom as the rate limiting step.The results showed the displacement of the first phenyl group is more facile than the second group.The largest difference in reactivities is found for the disilane.Competitive displacement reactions between various oligomers were analyzed to establish the influence of the chain length of oligosilanes on the relative reactivities of the terminal phenyl groups.Both the first and second phenyl group displacement reactions are faster for the longer chain oligomers than the shorter analogs.The 13C NMR spectra of the oligosilanes indicate the highest electron density on the ipso-carbon atoms in the disilane, in contrast to its lowest reactivity.This is interpreted by the increased stabilization of the positive charge in the transition state with an increase in the chain length.Thus, the reactivities of oligosilanes are governed by the structures of the transition states rather than the ground states.
- Ruehl, Karen E.,Matyjaszewski, Krzysztof
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