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1.
Xi-He Huang Tian-Lu Sheng Sheng-Chang Xiang Rui-Biao Fu Sheng-Min Hu Ya-Min Li Xin-Tao Wu 《Inorganic chemistry communications》2006,9(12):1304-1307
Hydrothermal reaction of CuCl2 · 2H2O, NaN3 with 1,4-dicyanobenzene in water/ethanol yielded a novel Cu(I)-tetrazolate, {Cu(cptz)}n, (1) (Hcptz is 5-(4-cyanophenyl)-tetrazole). The cptz ligand in the complex was generated in situ through the [2 + 3] cycloaddition reaction involving one of the two cyano-groups of the precursor 1,4-dicyanobenzene. The structure characterization shows that 1 possesses a 3D 4-connected SrAl2 topological network. Additionally, complex 1 exhibits strong yellow fluorescence at room temperature in the solid state. 相似文献
2.
Dmitrii V Ludin Sergey D Zaitsev Alexey V Markin Ivan D Grishin Semen S Sologubov Tatyana A Kovylina Igor L Fedushkin 《Polymer International》2022,71(1):86-97
We developed a new approach to obtain polylactide hybrid block copolymers with vinyl monomers (styrene, methyl methacrylate, methyl acrylate) through the realization of a reaction sequence using triethylborane and various p-quinones. The method offered includes two stages. In the first stage, a chain-transfer agent was obtained by borylation of the terminal hydroxyl groups of polylactide. The second stage was vinyl monomer radical polymerization in the presence of p-quinone accompanied by SH2-substitution at the boron atom.1,4-Naphthoquinone, 2,3-dimethyl-1,4-benzoquinone, duroquinone and 2,5-di-tert-butyl-1,4-benzoquinone were used as synthetic polymer chain growth mediators. It is shown that 1,4-naphthoquinone and 2,3-dimethyl-1,4-benzoquinone, similar in their characteristics, are effective agents providing the realization of reversible-deactivation radical polymerization. Realization of reversible-deactivation radical polymerization was proved with the analysis of the kinetics of block copolymerization, molecular weight characteristics and compositional homogeneity of block copolymers as well as its further capability to elongate the polymer chain. Synthesized block copolymers have a high thermal stability compared to the initial borylated polylactide. © 2021 Society of Industrial Chemistry. 相似文献
3.
The precipitation polymerization of ε-caprolactone has been assessed in water using various commercial metal triflates as catalysts. The reaction is quantitative at 70 and 100?°C, leading to number-average molecular weights up to 5,400?g/mol and dispersities around 1.5–2.0. A polycondensation mechanism operating from in situ generated 6-hydroxyhexanoic acid is proposed. Among various salts, aluminum and tin(II) triflates lead to the higher molecular weight after 24?h reaction at 70?°C. 相似文献
4.
Vinylic tellurides are of importance due to their useful behavior as synthons and intermediates. Recently, the use of these compounds in place of vinylic halides or triflates in the palladium-catalyzed cross-coupling reaction has emerged as a powerful tool in the preparation of conjugated enyne and enediyne. In this way, vinylic tellurides can behave as aryl or vinyl carbocation equivalents. This review focuses on methods that involve the use of vinylic tellurides in palladium-catalyzed cross coupling reaction. 相似文献
5.
1‐Dialkylamino‐3‐(trimethylsilyl)allenes 2a—q were obtained by conjugate addition of alkyl, vinyl, aryl, hetaryl, and silyl groups, via the respective organocuprates, to 3‐(trimethylsilyl)propyne iminium triflates 1a—d . Similarly, 2‐vinylidene‐2,3‐dihydro‐1,3‐benzothiazoles 4a,b were synthesized from semicyclic propyne iminium triflates 3a,b and a di‐tert‐butyl cuprate. 相似文献
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A simple method for synthesis of novel organogels based on multiwalled carbon nanotubes (MWCNTs) is reported. Three classes of organogels were synthesized by crosslinking polymerization of dodecyl methacrylate with various weight percentages of 1,4‐butanediol dimethacrylate, vinyl‐group‐modified MWCNTs or pristine MWCNTs in the presence of 2,2‐azoisobutyronitrile as initiator. In this reaction, the carbon nanotubes (CNTs) served simultaneously as an adsorbent, a comonomer and a crosslinking agent. The oil‐absorbent containing CNTs showed much higher swelling capacity in oil and organic solvents compared with that without CNTs. Therefore, CNT‐based organogels can be introduced as a promising candidate for environmental protection and oil recovery. © 2012 Society of Chemical Industry 相似文献
8.
Wolfram Uhlig 《Advanced Synthesis \u0026amp; Catalysis》1999,341(8):727-735
Treatment of 2,5‐dilithiothiophene with (dimethylamino) methylsilylbis(triflates) gave poly[(dimethylamino‐silylene)‐2,5‐thiophene] 4 in high yield. The amino–silyl bond was cleaved selectively by triflic acid leading to triflate substituted poly[(silylene)‐2,5‐thiophene] 5 . Conversions of this polymers with nucleophiles gave other functionalized derivatives 6 – 9 . Hydrosilylation reaction between silicon–vinyl and silicon–hydrogen derivatives results in polymer networks which may serve as interesting preceramic materials. The structures of the polymers were proven by NMR spectroscopy (29Si, 13C, 1H). 相似文献
9.
Over the past few years our group has described a new type of alkene difunctionalization reaction in which aryl or alkenyl triflates bearing tethered alkenes are coupled with various nucleophiles to afford carbocyclic products. The products are formed in moderate to good chemical yield, with generally high levels of stereoselectivity. Our progress to date in this area, which includes reactions of amine, alcohol, enolate, and indole nucleophiles, is described in this review. 相似文献
10.
The biphasic hydrogenations of a number of polymeric materials, polybutadiene (PBD), nitrile‐butadiene rubber (NBR) and styrene‐butadiene rubber (SBR), were investigated in a toluene/N,N′‐butylmethylimidazolium tetrafluoroborate, (BMI+BF4−) system with a water‐soluble analogue of Wilkinson's catalyst, RhCl(TPPTS)3 (TPPTS=triphenylphosphine, trisulfonated) at 100 °C and 3.1 MPa. The catalyst shows reasonable activity within ionic liquids with PBD although it was necessary in the case of NBR and SBR to add water as a co‐solvent to solubilize the catalyst within the ionic media. Both the extent of hydrogenation and the ratio of the internal 1,4‐olefins to vinyl 1,2‐olefins were monitored. A clear preference for the external olefins was observed even within NBR and SBR where functionalization on the polymer might enhance the degree of hydrogenation of the internal olefins. The effect of adding NaCl to the PBD system was also investigated. The addition of salt decreases the activity of the catalyst but has no effect on the preference for the hydrogenation of vinyl olefins. 相似文献
11.
The synthesis of vinyl‐substituted silphenylene‐siloxane polymer through B(C6F5)3 catalyzed polycondensation of 1,4‐bis(dimethylsilyl)benzene and vinylmethyldimethoxysilane is described. 1H‐NMR, 29Si‐NMR, and UV spectroscopy indicate that the vinyl groups remain undamaged during the polycondensation reaction. No hydrosilylation side reaction is observed under the reaction conditions. The microstructure of the polymer is not perfectly alternating with a randomization of 20%. The temperature for 5% mass loss is 430°C in inert atmosphere and 417°C in oxidative atmosphere with a residue of 56% at 700°C. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007 相似文献
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Kohji Masaki Shin‐Ichi Ohkawara Tomohiro Hirano Makiko Seno Tsuneyuki Sato 《应用聚合物科学杂志》2003,89(8):2095-2101
The crosslinking reaction of liquid carboxylated poly(acrylonitrile‐co‐butadiene) [or nitrile rubber (NBR); acrylonitrile = 10 wt %] with dicumyl peroxide (DCPO) was studied in dioxane by means of Fourier transform near‐infrared spectroscopy (FT‐NIR) and electron spin resonance spectroscopy (ESR). Among the three butadiene units (1,2, cis‐1,4, and trans‐1,4 units) of NBR, only the pendant vinyl group of the 1,2 unit showed an absorption at 6110 cm?1 from the FT‐NIR examination of dioxane solutions of NBR, 1‐octene, 3,3‐dimethyl‐1‐butene, trans‐2‐octene, cis‐5‐octen‐1‐ol, poly‐cis‐1,4‐butadiene, and poly‐1,2‐butadiene. The crosslinking reaction was followed in situ in dioxane by the monitoring of the disappearance of the pendant vinyl double bond with FT‐NIR. The initial disappearance rate (R0) of the vinyl group was expressed by R0 = k[DCPO]0.9[NBR]?0.2 (120°C). The overall activation energy of the reaction was calculated to be 20.7 kcal/mol. This unusual rate equation suggests unimolecular termination due to degradative chain transfer and depressed reactivity of the vinyl group caused by crosslinking. ESR study of the reaction mixture revealed that an allyl‐type polymer radical was formed in the reaction, and its concentration increased with time and was then saturated. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2095–2101, 2003 相似文献
14.
The Pd-catalyzed Mizoroki-Heck reaction of olefins with aryl halides, more often simply called the Heck reaction, was recently recognized with the 2010 Nobel Prize in chemistry. Although highly selective with electron-deficient olefins, which generally yield the linear β-arylated product exclusively, the Heck reaction is less satisfactory with electron-rich olefins. This substrate typically generates a mixture of both α- and β-arylated regioisomeric products, hampering wider application of the reaction in chemical synthesis. Pioneering studies by a number of researchers revealed that high α-regioselectivity could be obtained under Pd-diphosphine catalysis either through (i) the substitution of aryl triflates for halides or (ii) the addition of stoichiometric silver or thallium salts when aryl halides are used. Under these conditions, the arylation is believed to proceed via an ionic pathway. However, silver introduces added cost, thallium salts are toxic, and triflates are generally commercially unavailable, base sensitive, and thermally labile. Believing that the ionic pathway would be promoted in an ionic medium, in the early 2000s, we attempted the Pd-catalyzed arylation of the benchmark electron-rich olefin butyl vinyl ether with aryl bromides in an imidazolium ionic liquid. We were delighted to observe that highly regioselective α-arylation could readily be accomplished, with no need for silver additives, thallium additives, or aryl triflates. A range of other electron-rich olefins has since been shown to be viable as well. The high α-selectivity probably results from the high ionic strength of the medium, which facilitates the dissociation of halide anions from the [L(2)Pd(Ar)X] intermediate, channeling the arylation into the ionic pathway. Hydrogen bonding interactions may also play a role, however. We subsequently discovered that the α-arylation can indeed be significantly accelerated by a hydrogen bond donor salt, in both ionic liquids and common solvents. Evidence shows that the concentration of the cationic Pd(II)-olefin species along the ionic pathway is increased as a result of hydrogen bonding between the hydrogen bond donor and the halide anion. More recently, we reported that cheaper and greener alcohols allow the Heck arylation of electron-rich olefins to proceed in a much faster, productive, and totally α-regioselective manner, circumventing the need for an ionic medium or hydrogen bond donor salt. In particular, aryl chlorides with diverse properties have been demonstrated to be viable substrates for the first time. Significantly, it appears that ethylene glycol facilitates both the oxidative addition of ArCl to Pd(0) and the subsequent dissociation of chloride from Pd(II). A closely related reaction, acylation of aryl halides with aldehydes, was also developed. Proceeding via the intermediacy of an electron-rich enamine, this Pd-pyrrolidine cooperative catalysis affords alkyl aryl ketones in a straightforward manner, extending the Heck reaction from olefins to aldehydes. 相似文献
15.
Shoji Watanabe Kyoichi Suga Tsutomu Fujita Hideyuki Koiso 《Israel journal of chemistry》1975,13(3):257-260
This note describes a new preparative method of vinyl esters and diketones. Vinyl-magnesium chloride was added to benzoic acid in tetrahydrofuran to give a magnesium enolate. Without decomposition of the reaction mixture, propionyl chloride was added to give a mixture of 1-phenyl-1,4-pentadienyl propionate and 2-allyl-1-phenyl-pentane-1,3-dione. 相似文献
16.
Series of suspension copolymerization of vinyl chloride with various contents of 1-butene and 1-pentene (5–30 mass%) were carried out under the same reaction conditions. By applying a method which utilizes periodic sampling of heterogeneous reaction mixture from the reactor during the reaction and a gas chromatographic determination of unreacted vinyl chloride in the sample, the conversion curves of vinyl chloride were determined and the initial reaction rates were compared. 相似文献
17.
Tim Bowden Per J. Garegg Jean-Luc Maloisel Peter Konradsson 《Israel journal of chemistry》2000,40(3-4):271-277
Glycosylations using glucosyl bromides and various promoters (Et4NBr, HgBr2, or AgOTf) were investigated, competitively and kinetically. The reactions were found to be dependent in both glucosyl bromide and nucleophilic concentration, indicating a SN2-type rate, determining step. For the AgOTf promoted reaction an ion pair mechanism involving glucosyl triflates is suggested. 相似文献
18.
《Inorganic chemistry communications》2008,11(10):1270-1272
The equimolar reaction of tBuLi with 4-Cl-2,6-Me2-C6H2OH (ArOH) in 1,4-dioxane led to the unexpected formation of the mixed-anion, 1D polymer [(ArO)2(RO)4Li6 · (diox)]∞, 1 (where RO = H2CC(H)OCH2CH2O−). Incorporation of the alkoxy vinyl ether is due to cleavage of 1,4-dioxane by tBuLi. Compound 1 can also be prepared rationally by the reaction of nBuLi with ethylene glycol vinyl ether and ArOH in 1,4-dioxane solution. Direct lithiation of ethylene glycol vinyl ether results in the formation of the alkoxide [ROLi]12, 2. The crystal structure of 2 reveals an unusual truncated octahedral arrangement in the solid state, where each metal is chelated by a vinyl ether subunit. 相似文献
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