共查询到20条相似文献,搜索用时 31 毫秒
1.
Dr. Matthew M. D. Roy Samuel R. Baird Dr. Eike Dornsiepen Lucas A. Paul Linkun Miao Dr. Michael J. Ferguson Dr. Yuqiao Zhou Prof. Dr. Inke Siewert Prof. Dr. Eric Rivard 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(33):8572-8579
The synthesis of the new bulky vinyllithium reagent (MeIPr=CH)Li, (MeIPr=[(MeCNDipp)2C]; Dipp=2,6-iPr2C6H3) is reported. This vinyllithium precursor was found to act as a general source of the anionic 2σ, 2π-electron donor ligand [MeIPr=CH]−. Furthermore, a high-yielding route to the degradation-resistant SiII precursor MeIPr⋅SiBr2 is presented. The efficacy of (MeIPr=CH)Li in synthesis was demonstrated by the generation of a complete inorganic divinyltetrelene series (MeIPrCH)2E: (E=Si to Pb). (MeIPrCH)2Si: represents the first two-coordinate acyclic silylene not bound by heteroatom donors, with dual electrophilic and nucleophilic character at the SiII center noted. Cyclic voltammetry shows this electron-rich silylene to be a potent reducing agent, rivalling the reducing power of the 19-electron complex cobaltocene (Cp2Co). 相似文献
2.
gem-Chloroamine CF3CH(Cl)NHAc 1 reacts in a one-pot sequence with NaN3 to afford trifluoromethyl azido compound 2 and further undergoes a Huisgen 1,3-dipolar cycloaddition with alkynes to yield 1,4-disubstitued 1,2,3-triazoles. The reaction is catalyzed by Cu(II) species (Cu(OAc)2, 10 mol %) without any reducing agent, and the corresponding products are afforded in high yields (74-87%). This process offers thus an entry to new trifluoromethyl pseudopeptides. 相似文献
3.
A nickel‐catalyzed reductive coupling of aldehydes with alkynes using 1‐phenylethanol as reducing agent has been developed. The key achievement of this work is that we demonstrate environmentally benign 1‐phenylethanol can serve as a viable alternative reducing agent to Et3B, ZnEt2 and R3SiH for the nickel‐catalyzed reductive coupling reaction of aldehyde and alkynes. 相似文献
4.
Dr. Subramaniyan Mannathan Prof. Dr. Chien‐Hong Cheng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(37):11771-11777
A cobalt‐catalyzed reductive coupling of terminal alkynes, RC?CH, with activated alkenes, R′CH?CH2, in the presence of zinc and water to give functionalized trans‐disubstituted alkenes, RCH?CHCH2CH2R′, is described. A variety of aromatic terminal alkynes underwent reductive coupling with activated alkenes including enones, acrylates, acrylonitrile, and vinyl sulfones in the presence of a CoCl2/P(OMe)3/Zn catalyst system to afford 1,2‐trans‐disubstituted alkenes with high regio‐ and stereoselectivity. Similarly, aliphatic terminal alkynes also efficiently participated in the coupling reaction with acrylates, enones, and vinyl sulfone, in the presence of the CoCl2/P(OPh)3/Zn system providing a mixture of 1,2‐trans‐ and 1,1‐disubstituted functionalized terminal alkene products in high yields. The scope of the reaction was also extended by the coupling of 1,3‐enynes and acetylene gas with alkenes. Furthermore, a phosphine‐free cobalt‐catalyzed reductive coupling of terminal alkynes with enones, affording 1,2‐trans‐disubstituted alkenes as the major products in a high regioisomeric ratio, is demonstrated. In the reactions, less expensive and air‐stable cobalt complexes, a mild reducing agent (Zn) and a simple hydrogen source (water) were used. A possible reaction mechanism involving a cobaltacyclopentene as the key intermediate is proposed. 相似文献
5.
T. P. Sterenchuk L. B. Belykh N. I. Skripov S. B. Sanzhieva K. L. Gvozdovskaya F. K. Schmidt 《Kinetics and Catalysis》2018,59(5):585-592
The effect of the composition of the catalytic system and the size of particles on the properties of palladium catalysts in 2-ethyl-9,10-anthraquinone hydrogenation was studied. It was shown that, depending on the nature of a reducing agent (H2, AlEt3), palladium species formed in the absence of a modifying agent catalyze various side processes to a substantial extent together with 2-ethyl-9,10-anthraquinone hydrogenation: mostly hydrogenolysis (in the case of H2 as a reducing agent) and hydrogenation of aromatic rings in 2-ethyl-9,10-anthrahydroquinone (in the case of AlEt3 as a reducing agent). Elementary phosphorus was found to have a promoting effect on the selectivity of palladium catalysts in the synthesis of hydrogen peroxide by the anthraquinone method. The main factors that make it possible to control the selectivity of palladium catalysts were discussed. 相似文献
6.
Byung Woo Yoo Min Kyung Lee Cheol Min Yoon 《Phosphorus, sulfur, and silicon and the related elements》2016,191(6):807-810
The TaCl5/In system was found to be a new reagent for reducing a wide range of structurally diverse sulfoxides to the corresponding sulfides with high yields under mild conditions. This protocol is chemoselective and tolerates several functional groups, such as Br, Cl, OCH3, CHO, and CH = CH2. 相似文献
7.
Different new catalysts based on transition metal compounds of groups IVb, Vb, VIb and VIIIb combined with a reducing agent such as: triethylaluminium and butyllithium in various solvents; toluene and silicone oil, were used for the polymerization of acetylene. By changing the catalyst, cocatalyst, solvent and polymerization conditions, a large variety of polyacetylenes were obtained. The polyacetylenes were characterized by SEM, FTIR and C13 NMR spectroscopies. Some of the new polymers were stretched mechanically and then doped with iodine. Thus highly conducting thick (20μm) and transparent films (0.1 μm) were obtained, with conductivities of 20000 ω−0.cm−1 and 8000 ω−1.cm−1, respectively. After modification of the standard catalyst system (Ti(OC4H9) 4-Al (C2H5) 3-silicone oil) by the introduction of some additional reducing agents, conductivities as high as 120000 ω−1.cm−1, after elongation and iodine doping of the polymers, were reached. In this paper we present also a comparative stability study of the new (CH)x films and powders. 相似文献
8.
Andrew J. Cornish Michael F. Lappert Grace L. Filatovs Terence A. Nile 《Journal of organometallic chemistry》1979,172(2):153-163
The catalytic activity of tris(pentanedionato)rhodium(III), (or rhodium(III) acetylacetonate) (I) has been investigated for the hydrosilylation of a variety of organic substrates: alkenes, terminal or internal acetylenes, conjugated dienes, or α,β-unsaturated carbonyls or nitriles. With PhCHCH2 or PhCH2CHCH2, ω-substitution was unexpectedly observed, as well as addition. Compound I is an active hydrosilylation catalyst in the absence of any added reducing agent, as is tetrakis(μ-acetato)dirhodium(II) (II) which does not, however, show any unusual catalytic activity due to the two metal atom cluster. Possible mechanisms are suggested. 相似文献
9.
1,5-Diphosphabicyclo [3.3.1]nonane 1,5-Diphosphabicyclo[3.3.1]nonane 8 has been obtained by free-radical cyclization of CH2?CHCH2(H)PCH2P(H)CH2CH?CH2 6 and 1-allyl-1,3-diphosphorinane 7 . For the synthesis of 6 and 7 the chlorophosphine Cl2PCH2PCl2 1 is used as a starting material, which can be converted into Me2N(Cl)PCH2P(Cl)NMe2 3 by reaction with (Me2N)2PCH2P(NMe2)2 2 . Treatment of 3 with two equivalents of allyl lithium and cleavage of the PN bonds in CH2?CHCH2(Me2N)PCH2P(NMe2)CH2CH?CH2 4 with diluted HCl affords CH2?CHCH2(H)(O)PCH2P(O)(H)CH2CH?CH2 5 . Phenylsilane is used for the first time as a reducing agent to obtain a secundary phosphine like 6 from the secundary phosphine oxide ( 5 ). Prolonged heating increases the yield of the byproduct 7 in the mixture of 6 and 7 . Reactions of the trivalent phosphorus in 8 with CS2, CH3I, POCl3, NO, sulfur, and KSeCN, respectively, delivers the corresponding derivatives 9–17 . The compounds decribed are characterized by 1H, 13C, 31P, 77Se n.m.r., i.r., and m.s. data. 相似文献
10.
Four kinds of palladium catalysts dispersed on poly-N-vinyl-2-pyrrolidone were prepared by using CH3OH-NaOH,NaBH4,H2O or CH3OH-H2O as the reducing agent in the process of catalyst preparation. The catalysts were characterized by XPS,TEM,XRD and used for the hydrogenation of methyl acrylate.It was found that the valence state of palladium and distribution of palladium particles as well as the hydrogenation rate were greatly affected by the reducing agent.The best evenly dispersed palladium catalyst showing high hydrogenation activity was prepared using CH3OH-NaOH as the reducing agent. 相似文献
11.
Tianle Zhu Jiming Hao Lixin Fu Junhua Li Zhiming Liu 《Reaction Kinetics and Catalysis Letters》2005,84(1):61-67
Summary The cooperation effect of reducing species for selective reduction of NO over Ag/Al2O3 has been investigated in the presence of excess oxygen. When the combinations of propene or propane and ethanol or methanol were used as reducing agents, NO reduction took place over a wider temperature range, compared with a single hydrocarbon as reducing agent. 相似文献
12.
Danfeng Yang Dan He Yonggui Liao Zhigang Xue Xingping Zhou Xiaolin Xie 《Journal of polymer science. Part A, Polymer chemistry》2014,52(7):1020-1027
The polar solvents, N‐methylpyrrolidone (NMP), N,N‐dimethylformamide (DMF), and acetonitrile (CH3CN) were used as ligands for iron(III)‐mediated activators generated by electron transfer atom transfer radical polymerizations (AGET ATRPs) of methyl methacrylate (MMA) with various initiators and reducing agents. Polymerizations were conducted with a molar ratio of [MMA]0/[initiator]0/[FeBr3]0/[reducing agent]0 = 100:1:1:0.5 and a volume ratio of MMA/solvent = 2:1 at 60 °C to investigate the effects of initiator, solvent and reducing agent, and most of the systems showed the typical features of “living”/controlled radical polymerization. In order to get a deeper understanding of the mechanism, the amount of the reducing agent was changed to study the polymerization behavior. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1020–1027 相似文献
13.
Treatment of 1,1,4,4-tetramethyl-1,4-distanna-2,5-cyclohexadiene with organoboron dihalides or boron trihalides generally leads to organoboron polymers and (CH3)2SnX2 (X Cl, Br). Ferrocenyldibromoborane, FcBBr2 (Fc (C5H5)Fe(C5H4)), reacts atypically with formation of FcB(CH CH)2BFc, which on controlled methanolysis affords CH3OB(CH CH)2BOCH3. The new 1,4- dibora-2,5-cyclohexadienes are characterized as nickel complexes Ni[FcB(CH CH)2BFc](CO)2 and Ni[CH3OB(CH CH)2BOCH3]2, respectively. 相似文献
14.
The technique for growing CH3NH3PbI3 single crystals from saturated solutions in concentrated hydroiodic acid is improved by introducing a reducing agent (hypophosphorous acid). The structure of perovskite is confirmed by single crystal XRD. By energy dispersive spectroscopy and X-ray photoelectron spectroscopy it is established that the stoichiometry of the grown crystals corresponds to the CH3NH3PbI3 compound. Changes in the photoluminescence intensity during in-air measurements show that the crystals synthesized using the reducing agent are more stable in the external environment with laser exposure than without it. 相似文献
15.
Sheng Hua Liu 《Journal of organometallic chemistry》2003,683(2):331-336
Treatment of [Ru(CHCHCH2PPh3)X(CO)(PPh3)2]+ (X=Cl, Br) with KTp (Tp=hydridotris(pyrazolyl)borate) and NaBPh4 produced [TpRu(CHCHCH2PPh3)(CO)(PPh3)]BPh4. Reaction of RuHCl(CO)(PPh3)3 with HCCCH(OEt)2 produced Ru(CHCHCH(OEt)2)Cl(CO)(PPh3)2, which reacted with KTp to give TpRu(CHCHCHO)(CO)(PPh3). Treatment of [TpRu(CHCHCH2PPh3)(CO)(PPh3)]BPh4 with NaN(SiMe3)2 and benzaldehyde produced TpRu(CHCHCHCHPh)(CO)(PPh3). The later complex was also produced when TpRu(CHCHCHO)(CO)(PPh3) was treated with PhCH2PPh3Cl/NaN(SiMe3)2. The bimetallic complex [TpRu(CO)(PPh3)]2(μ-CHCHCHCHC6H4CHCHCHCH) was obtained from the reaction of [TpRu(CHCHCH2PPh3)(CO)(PPh3)]BPh4 with NaN(SiMe3)2 and terephthaldicarboxaldehyde. 相似文献
16.
Saddam Saqib Wajid Zaman Fazal Ullah Imran Majeed Asma Ayaz Muhammad Farooq Hussain Munis 《应用有机金属化学》2019,33(11)
The ever‐increasing resistance of plant microbes towards fungicides and bactericides has been causing serious threat to plant production in recent years. For the development of an effective antifungal agent, we introduce a novel hydrothermal protocol for synthesis of chitosan iron oxide nanoparticles (CH‐Fe2O3 NPs) using acetate buffer of low pH 5.0 for intermolecular interaction of Fe2O3 NPs and CH. The composite structure and elemental elucidation were carried out by using X‐ray power diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X‐ray (EDX), Transmission Electron Microscopy (TEM), Fourier Transformed Infrared Spectroscopy (FTIR) and Ultraviolet Visible Absorption Spectroscopy (UV–vis spectroscopy). Additionally, antifungal activity was evaluated both In vitro and In vivo against Rhizopus oryzae which is causing fruit rot disease of strawberry. We compared different concentrations (0.25%, 0.50%, 075% and 1%) of CH‐Fe2O3 NPs and 50% synthetic fungicide (Matalyxal Mancozab) to figure out suitable concentration for application in the field. XRD analysis showed a high crystalline nature of the NPs with average size of 52 nanometer (nm). SEM images revealed spherical shape with size range of 50–70 nm, whereas, TEM also revealed spherical shape, size ranging from 0 nm to 80 nm. EDX and FTIR results revealed presence of CH on surface of Fe2O3 NPs. The band gap measurement showed peak 317–318 nm for bare Fe2O3 NPs and CH‐Fe2O3 NPs respectively. Antifungal activity in both In vitro and In vivo significantly increased with increase in concentration. The overall results revealed high synergetic antifungal potential of organometallic CH‐Fe2O3 NPs against Rhizopus oryzae and suggest the use of CH‐Fe2O3 NPs against other Phyto‐pathological diseases due to biodegradable nature. 相似文献
17.
A silver‐mediated oxidative trifluoromethylation of easily accessible α‐trifluoromethyl alcohols with TMSCF3 was developed to access novel CF3(OCF3)CH‐containing compounds. Deprotonation of CF3(OCF3)CH‐substituted arenes afforded synthetically useful CF3O‐substituted gem‐difluoroalkenes. Furthermore, evaluation of the lipophilicities (log P) indicated that CH(OCF3)CF3 is more lipophilic than the common fluorinated motifs such as CF3, OCF3, and SCF3, thus rendering the CH(OCF3)CF3 motif appealing in drug discovery. 相似文献
18.
The mechanism on the OH‐initiated atmospheric oxidation reaction of (Z)‐CF3CH?CHCF3 with and without O2/NO has been investigated theoretically. The electronic structure information of the potential energy surface was obtained at the M06‐2X/aug‐cc‐pVDZ level, and the single‐point energies were refined by MCG3/3 method. The calculations show that the (Z)‐CF3CH?CHCF3 + OH reaction occurs via addition‐elimination mechanism, leading to products CF3 and CF3CH?CH(OH), rather than H‐abstraction mechanism at low temperature. Under atmospheric condition, the OH‐addition intermediate is likely to react rapidly with O2/NO, and the likely products are CF3C(O)H, CF2(O), CF3CH(OH)CH(O), FNO, and HO2, as is proposed by experiment. © 2013 Wiley Periodicals, Inc. 相似文献
19.
Lihua Feng Prof. Wenqin Wang Xiyong Li Prof. Tao Chen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(71):16377-16381
Fabricating three-dimensional (3D) hierarchical noble-metal particles by spontaneous redox reactions between graphene and noble-metal salts still remains a great challenge. Herein, the fact that graphene oxide (GO) itself acts as both a platform for grafting polymer brushes and a reducing agent to reduce [Ag(NH3)2]+ ions is taken advantages of. 3D flower-like Ag mesoparticles (Ag mesoflowers, Ag MFs) with tunable size and shapes can spontaneous grow on poly(4-vinylpyridine) brushes-grafted-graphene oxide (P4VP-g-GO) films in Ag(NH3)2OH solution without the use of any additional reducing agent. The residual Ag(NH3)2OH on 3D Ag MFs surface can be further reduced by NaBH4, causing abundant nanoporosities over the entire Ag MFs. The resulting Ag nanoporous MFs (Ag NMFs) with larger surface-to-volume ratio and higher nanoscale roughness exhibit ultrasensitivity in surface-enhanced Raman spectroscopy (SERS) detection, and the detection limit for 4-aminothiophenol is as low as 10−13 m . 相似文献
20.
The reduction of alkenes has been achieved using NaBH4 as the reducing agent using 0.5-1.0 mol % Ru(PPh3)4H2 in the presence of water. 相似文献