- Synthesis of 1,1-Diisopropyl- or -Diphenyl -2,5-dibromo- or -bis(trimethylsilyl)-3,4-diphenyl-siloles and the Electrochemical Properties as Anode Materials for Lithium-Ion Battery
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Intramolecular cyclization of 1,1-diisopropyl- or diphenyl-bis(phenylethynyl)-silanes (2a and 2b) followed by bromination or trimethylsilylation were carried out to yield 1,1-diisopropyl- or -diphenyl-3,4-diphenyl-2,5-dibromo-siloles (3a and 3b) and 1,1-d
- Cho, Yoon-ho,Jung, Young Min,Park, Young Tae
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- Preparation and photoelectronic and electrochemical properties of oligo[(1,1-diisopropyl-3,4-diphenyl-2,5-silolene)-co-(alkylphenylsilylene)]s
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We oligomerized 2,5-dibromo-1,1-diisopropyl-3,4-diphenyl-2,5-silole with dichloroalkylphenylsilanes utilizing n-BuLi to yield conjugated oligo[(1,1-diisopropyl-3,4-diphenyl-2,5-silolene)-co-(alkylphenylsilylene)] s. Gel permeation chromatography measurements confirm that the synthesized materials are oligomeric. In addition, the prepared oligomers show characteristic diene stretching bands at 1579-1599 cm?1in their FT-IR spectra. Furthermore, the oligomers are highly soluble in common organic solvents such as tetrahydrofuran and chloroform. In tetrahydrofuran, the oligomers show strong maximum electronic absorption bands at 253–292 nm with molar absorptivities of 1.61 × 102to 2.57 × 104/cm M in their UV-vis electronic absorption spectra, indicating that the maxima are red-shifted by 5–8 nm compared to the 2,5-dibromo-1,1-diisopropyl-3,4-diphenyl-2,5-silole monomer, strong maximum electronic excitation bands at 292–312 nm, and strong maxima electronic emission bands at 385–396 nm in the emission fluorescence spectra. The emission and absorption spectra strongly suggest that the prepared silole-containing oligomers may be conjugated through the oligomer backbone. In particular, cyclic voltammetry measurements of oligo[(1,1-diisopropyl-3,4-diphenyl-2,5-silolene)-co-(diphenylsilylene)] deposited on a glassy carbon electrode in 1.0 M aqueous hydrogen chloride show two oxidation potentials at 0.98 and 1.61 V vs. Ag/Ag+, and two reduction potentials at 0.00 and ?1.93 V vs. Ag/Ag+. The oligomers were stable on heating to 200 _C under nitrogen, as determined by thermogravimetric analysis, losing between 4% and 23% of their starting weights.
- Jung, Young Min,Baek, Seong-Ho,Park, Young Tae
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- Synthesis and electrochemical characteristics of oligo[{3,4-diphenyl-1,1-di(propan-2-yl)-2,5-silolene}-co-(diphenylsilylene)] for lithium-ion secondary battery anodes
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The co-oligomerization of 2,5-dibromo-3,4-diphenyl-1,1-di(propan-2-yl)-silole (3) with dichlorodiphenylsilane was carried out using n-butyllithium at ?78°C to synthesize oligo[{3,4-diphenyl-1,1-di(propan-2-yl)-2,5-silolene}-co-(diphenylsilylene)] (5) as yellowish-white powder, with a mass-average molar mass of 561, polydispersity of 1.01, λabs,max of 260 and 279 nm, λex,max of 296 nm, λem,max of 391 nm, and thermal stability up to 125°C without any weight loss. The rate performance obtained with oligomer 5 was superior to that obtained with monomer 3. The discharge and charge capacities with 5 were 1234 and 1263 mAhg?1, respectively, with Coulombic efficiency of 97.7% at the 100th cycle. Nyquist plots suggested that the resistance decreases gradually with repeated cycling.
- Jung, Young Min,Park, Young Tae
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p. 1574 - 1578
(2021/09/30)
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- Grignard metathesis polymerization and properties of 1,1-disubstituted-2,5- dibromo-3,4-diphenylsiloles
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Grignard metathesis polymerizations of 1,1-disubstituted-2,5-dibromo-3,4- diphenylsiloles such as 1,1-dimethyl-2,5-dibromo-3,4-diphenylsilole, 1,1-diethyl-2,5-dibromo-3,4-diphenylsilole, 1,1-diisopropyl-2,5-dibromo-3,4- diphenylsilole, and 1,1-dihexyl-2,5
- Park, Young Tae
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p. 1825 - 1831
(2014/07/07)
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- 2,5-reactive substituent group-containing siloles, silole polycondensates and preparation thereof
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2,5-Reactive substituent group-containing siloles of the following general formula are provided STR1 wherein R1 to R4 may be the same or different and independently represent a monovalent hydrocarbon group having from 1 to 12 carbon atoms or a hydrogen atom, and R5 and R6 may be the same or different and independently represent a group selected from monovalent hydrocarbon-substituted sulfur, selenium, silicon, germanium, tin and phosphorus, or a halogen atom. Polycondensates of the siloles and processes for preparing the siloles and polycondensates are described.
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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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