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241.
A Germylene/Borane Lewis Pair and the Remarkable C=O Bond Cleavage Reaction toward Isocyanate and Ketone Molecules
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Jiancheng Li Bin Li Rui Liu Liuyin Jiang Prof. Dr. Hongping Zhu Prof. Dr. Herbert W. Roesky Sayan Dutta Dr. Debasis Koley Prof. Weiping Liu Qingsong Ye 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(41):14499-14503
A germylene/borane Lewis pair ( 2 ) was prepared from a 1,1‐carboboration of amidinato phenylethynylgermylene ( 1 ) by B(C6F5)3. Compound 2 reacted with iPrNCO and (4‐MeOC6H4)C(O)Me, respectively, with cleavage of the C=O double bond. In the first instance, O and iPrNC insert separately into the Ge?B bond to yield a GeBC2O‐heterocycle ( 3 ) and a GeBC3‐heterocycle ( 4 ). In the second case (4‐MeOC6H4)(Me)C inserts into the Ge?N bond of 2 while O is incorporated in the Ge?B bond to form a Ge‐centered spiroheterocycle ( 5 ). The reaction of 2 with tBuNC to give 6 , which has almost the same structure as 4 , proved the formation of the isonitrile during transformation from 2 and iPrNCO to 3 and 4 . The kinetic study of the reaction of 2 and iPrNCO gave evidence of proceeding through a GeBC3O‐heterocycle intermediate. In addition, a DFT study was performed to elucidate the reaction mechanism. 相似文献
242.
Without any other additives or additional energy, Au nanoplates have been successfully prepared and integrated simultaneously with the dedoped polypyrrole nanofiber film via the in situ reduction of AuCl4– on the film surface. The morphology and structure of the as‐prepared composite film are characterized, and its application for surface‐enhanced Raman scattering is also investigated. It has been found that the morphology of as‐prepared Au nanoplates is dependent on the reaction duration, while the density is dependent on the concentration of AuCl4– ions in the reaction process. It is suggested that polypyrrole plays dual reducing and structure‐directing roles during the formation of Au nanoplates. Surface‐enhanced Raman scattering study shows that the Au nanoplates give an intensive and enhanced Raman scattering when 4‐aminothiophenol is used as a probing molecule. The employed approach may shed some light on simultaneously fabricating and immobilizing other noble metal micro/nanostructures with unique morphology. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
243.
Reactions of LGeMe (L = HC[C(Me)N-2,6-iPr(2)C(6)H(3)](2)) with 0.25 or 0.5 equiv of (CuC(6)F(5))(4) gave the products [LGe(Me)CuC(6)F(5)](2) (1) and [LGe(Me)(CuC(6)F(5))(2)](2) (2), respectively. In situ formed 1 reacted with 0.5 equiv of (CuC(6)F(5))(4) to give 2 on the basis of NMR ((1)H and (19)F) spectral measurements. Conversely, 2 was converted into 1 by treatment with 2 equiv of LGeMe. Reactions of LGeC(SiMe(3))N(2) with 1 or 2 equiv of AgC(6)F(5)·MeCN produced the corresponding compounds LGe[C(SiMe(3))N(2)]AgC(6)F(5) (3) and {LGe[C(SiMe(3))N(2)](AgC(6)F(5))(2)}(2) (4). Similarly, 3 was converted into 4 by treatment with 1 equiv of AgC(6)F(5)·MeCN and 4 converted into 3 by reaction with 2 equiv of LGeC(SiMe(3))N(2). X-ray crystallographic studies showed that 1 contains a rhombically bridged (CuC(6)F(5))(2), while 2 has a chain-structurally aggregated (CuC(6)F(5))(4), both supported by LGeMe. Correspondingly, 3 showed a terminally bound AgC(6)F(5) and 4 a chain-structurally aggregated (AgC(6)F(5))(4), both supported by LGeC(SiMe(3))N(2). Photophysical studies proved that the Ge-Cu metal-metalloid donor-acceptor bonding persists in solutions of 1 and 2 and Ge-Ag donor-acceptor bonding in solutions of 3 and 4 as a result of the clear migration of their emission bands compared to those of the corresponding starting materials. Low-temperature (-50 °C) (19)F NMR spectral measurements detected dissociation of 1, 2, and 4 by the aggregation part of the CuC(6)F(5) or AgC(6)F(5) entities in solution. These results provide good support for pentafluorophenylcopper(I) or -silver(I) species having β-diketiminate germylene as a donor because of its remarkably electronic and steric character. 相似文献
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Bimetallic Fe‐V‐HMS (HMS, hexagonal mesoporous silica) catalysts with various molar ratios of iron to vanadium were synthesized using a co‐synthesis method, and investigated for oxidative desulfurization of dibenzothiophene (DBT) using tert‐butyl hydroperoxide as an oxidant. The catalysts were characterized using X‐ray diffraction, temperature‐programmed desorption of ammonia, Fourier transform infrared spectroscopy and N2 physical adsorption–desorption techniques. The Fe‐V‐HMS catalyst with a 2:1 molar ratio of iron to vanadium exhibited the highest total acidity and the highest catalytic activity. DBT was almost completely oxidized to dibenzothiophenesulfone, a species with a higher polarity that could be subsequently adsorbed on the Fe‐V‐HMS, and therefore the Fe‐V‐HMS acts as both a catalyst and an adsorbent simultaneously. The desulfurization rate was 98.1%. A pseudo‐first‐order model was fitted to the experimental data, and the activation energy was found to be 38.79 kJ mol?1. The encouraging performance of Fe‐V‐HMS offers the prospect of the design of a one‐pot oxidative desulfurization process without needing extraction of sulfones from fuel oil with a chemical solvent. 相似文献
247.
Qu Ying Chen Lei Deng Hongping Li Chunya 《Journal of Solid State Electrochemistry》2017,21(11):3281-3287
Journal of Solid State Electrochemistry - Poly-L-lysine functionalized reduced graphene oxide nanosheets (PLL-rGO) were prepared and thoroughly characterized with transmission electron microscopy,... 相似文献
248.
Synthesis and characterization of titania/MQ silicone resin hybrid nanocomposite via sol–gel process
Hongping Xiang Jianfeng Ge Shaohui Cheng Hongmei Han Shaowei Cui 《Journal of Sol-Gel Science and Technology》2011,59(3):635-639
Inorganic–organic hybrid materials were prepared via an aqueous sol–gel technique from tetra-n-butyl titanate as the precursor of titania, in the presence of MQ silicone resin. The samples were characterized by FT–IR,
UV–Vis, DSC, TGA, SEM and XRD. It was illustrated that the Ti–O–Si covalent bonds had formed in the hybrid nanocomposite which
were highly transparent in visible light region, and yet had high absorption in UV light range. The thermal stability of the
hybrid materials was gradually improved with the increase of titania content. It was concluded that the hybrid material which
particle size was around 50 nm were amorphous when the crystallization of titania was retarded by MQ silicone resin. 相似文献
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The reaction of LAlH(2) (L = HC(CMeNAr)(2), Ar = 2,6-iPr(2)C(6)H(3)) (1) with 3-methylphenylboronic acid and 3-fluorophenylboronic acid resulted in the boroxine-linked aluminum compounds LAl[OB(3-CH(3)C(6)H(4))](2)(μ-O) (2) and LAl[OB(3-FC(6)H(4))](2)(μ-O) (3), respectively. LAl[OB(2-PhC(6)H(4))(OH)](2) (4) was synthesized by the reaction of 1 with 2-biphenylboronic acid. Compound 4 is the intermediate analogue to those, which we postulated for the formation of 2 and 3. The reaction of 1 with 3-hydroxyphenylboronic acid resulted in the first metal benzoboroxole oxide LAl[OB(o-CH(2)O)C(6)H(4)](2) (5), which is formed from a compound with B-(OH)(2) and C-OH functionalities. 相似文献