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Meng‐Jiao Wang Sharon X. Lu Khaled Mahmud 《Journal of Polymer Science.Polymer Physics》2000,38(9):1240-1249
Dynamic properties such as shear modulus, loss modulus, and loss factor were obtained at a low strain amplitude over a wide range of frequencies and temperatures on vulcanizates filled with carbon black, silica, and carbon–silica dual‐phase filler. The data were shifted along the frequency scale. Instead of a single smooth master curve, a pseudomaster curve with a feather‐like structure is obtained. This effect is especially pronounced for the loss factor. Multiple factors may be responsible for this. Among others, filler networking and polymer–filler interaction may play a dominant role. The effect of the carbon–silica dual‐phase filler on the overall dynamic properties of the vulcanizates is similar to that of silica. Their tan δ values are much lower at lower frequencies and are relatively higher at higher frequencies. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 1240–1249, 2000 相似文献
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Soichiro Nakatsuka Yusuke Watanabe Yoshinobu Kamakura Satoshi Horike Daisuke Tanaka Takuji Hatakeyama 《Angewandte Chemie (International ed. in English)》2020,59(4):1435-1439
A triphosphaazatriangulene (H3L) was synthesized through an intramolecular triple phospha‐Friedel–Crafts reaction. The H3L triangulene contains three phosphinate groups and an extended π‐conjugated framework, which enables the stimuli‐responsive reversible transformation of [Cu(HL)(DMSO)?(MeOH)]n, a 3D‐MOF that exhibits reversible sorption characteristics, into (H3L?0.5 [Cu2(OH)4?6 H2O] ?4 H2O), a 1D‐columnar assembled proton‐conducting material. The hydrophilic nature of the latter resulted in a proton conductivity of 5.5×10?3 S cm?1 at 95 % relative humidity and 60 °C. 相似文献
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Back Cover: Ultrasound‐Driven Secondary Self‐Assembly of Amphiphilic β‐Cyclodextrin Dimers (Chem. Eur. J. 13/2015)
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Hai‐tao Zhang Prof. Dr. Xiao‐dong Fan Prof. Dr. Wei Tian Rong‐tian Suo Zhen Yang Yang Bai Wan‐bin Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(13):5256-5256
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Synthesis and Characterization of (2E,2 E)‐3,3‐((9,9‐diocyl‐9H‐flourene‐2,7‐diyl)bis(4,1‐phenylene))bis(2‐cyanoacylic acid) as a Symmetrical Metal‐free Organic Dye
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In this study a novel symmetrical metal‐free organic dye for applications in dye‐sensitized solar cells (DSSCs) was synthesized. This dye ( D ) was designed with A–π–D–π–A framework and synthesized with 9,9‐dioctylfluorene as electron donor, phenylene as π‐spacer and cyanoacetic acid as electron acceptor. The chemical structure of product was determined using UV‐Vis, FT‐IR, CNMR, HNMR spectroscopy techniques. The presence of a phenylene π‐bridge between the donor and the acceptor units and the di‐anchoring moieties in this structure led to enhancement of conjugation lengths and molar extinction coefficient (ε) that is promising for further improvement of the conversion efficiency of DSSCs. 相似文献
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Hydrogenation of polystyrene‐b‐polybutadiene‐b‐polystyrene mediated by group (IV) metal metallocene complexes
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Cheng‐Hung Chiang Jing‐Cherng Tsai 《Journal of polymer science. Part A, Polymer chemistry》2017,55(13):2141-2149
Various group (IV) metal complexes, namely bis(cyclopentadienyl) titanium dichloride, bis(pentamethylcyclopentadienyl) titanium dichloride, cyclopentadienyl titanium trichloride, pentamethylcyclopentadienyl titanium trichloride, bis(cyclopentadienyl) zirconium dichloride, and bis(cyclopentadienyl) hafnium dichloride, were used as the catalysts for mediating styrene–butadiene–styrene hydrogenation. The catalytic efficiency of these catalysts was examined. The results show that catalyst activity strongly depends on the chemical structure of the metallocene complex. We also found that trialkylaluminum has a significant influence on the hydrogenation activity and thermal stability of metallocene catalysts. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2141–2149 相似文献
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Pengfei Xu Yonggui Song Bingwei Feng Qiang Zeng Baixi Shan Kuangyi Liu Dan Su 《Biomedical chromatography : BMC》2019,33(1)
Keke capsule as a traditional Chinese medicine formulation is used to relieve cough, for analgesia and to reduce bronchial asthma. The multi‐components are absorbed into the blood and brain after oral administration of Keke capsule, with no systematic investigation so far. A reliable and rapid UPLC–QTOF–MSE combined with a data processing software platform was used to characterize the components of Keke capsule and simultaneously identify bioactive components in blood and brain tissues in rat after oral administration. Consequently, a total of 41 components of Keke capsule, including alkaloids, flavone, flavonols, triterpene, lignanoid, organic acids, glycosides and coumarin were identified. Twenty‐one components were found in plasma, including 18 prototypes and three metabolites; 15 components were found in brain tissues, including 10 prototypes and five metabolites. Alkaloids and flavonoids in Keke capsule were the main components which were absorbed into blood. The main alkaloids of Keke capsule can pass through the blood–brain barrier and show different distribution tendencies in brain tissues. The main components of keke capsule was simultaneously analyzed by throughput analysis, and the corresponding bioactive components were examined by blood‐brain barrier in the rat after oral administration of the capsule. 相似文献
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Cover Picture: Selective Synthesis of Partially Protected Nonsymmetric Biphenols by Reagent‐ and Metal‐Free Anodic Cross‐Coupling Reaction (Angew. Chem. Int. Ed. 39/2016)
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Anton Wiebe Dr. Dieter Schollmeyer Dr. Katrin M. Dyballa Prof. Dr. Robert Franke Prof. Dr. Siegfried R. Waldvogel 《Angewandte Chemie (International ed. in English)》2016,55(39):11689-11689
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A Boiling‐Water‐Stable,Tunable White‐Emitting Metal–Organic Framework from Soft‐Imprint Synthesis
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Prof. Jun He Jian Huang Yonghe He Peng Cao Dr. Matthias Zeller Dr. Allen D. Hunter Prof. Zhengtao Xu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(5):1597-1601
A new avenue for making porous frameworks has been developed by borrowing an idea from molecularly imprinted polymers (MIPs). In lieu of the small molecules commonly used as templates in MIPs, soft metal components, such as CuI, are used to orient the molecular linker and to leverage the formation of the network. Specifically, a linear dicarboxylate linker with thioether side groups reacted simultaneously with Ln3+ ions and CuI, leading to a bimetallic net featuring strong, chemically hard Eu3+–carboxylate links, as well as soft, thioether‐bound Cu2I2 clusters. The CuI block imparts water stability to the host; with the tunable luminescence from the lanthanide ions, this creates the first white‐emitting MOF that is stable in boiling water. The Cu2I2 block also readily reacts with H2S, and enables sensitive colorimetric detection while the host net remains intact. 相似文献
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Acid–Base‐Responsive Intense Charge‐Transfer Emission in Donor–Acceptor‐Conjugated Fluorophores
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Herein we report on the synthesis and acid‐responsive emission properties of donor–acceptor (D–A) molecules that contain a thienothiophene unit. 2‐Arylthieno[3,2‐b]thiophenes were conjugated with an N‐methylbenzimidazole unit to form acid‐responsive D–A‐type fluorophores. The D–A‐conjugated fluorophores showed intense intramolecular charge‐transfer (ICT) emission in response to acid. The effect of the substitution on their photophysical properties as well as their solvent‐dependence indicated non‐twisting ICT emission in protonated D–A molecules. The quinoidal character of 2‐arylthienothiophene as a donor part is discussed, as it is assumed that it contributes to suppression of the molecular twisting in the excited state, therefore decreasing the nonradiative rate constant, thereby resulting in the intense ICT emission. Acid–base‐sensitive triple‐color emission was also achieved by the introduction of a base‐responsive phenol group in the donor part. 相似文献
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A highly efficient heterogeneous montmorillonite K‐10‐supported palladium catalyst for Suzuki–Miyaura cross‐coupling reaction in aqueous medium
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A heterogeneous montmorillonite K‐10‐supported palladium triphenylphosphine catalyst is reported for the Suzuki–Miyaura cross‐coupling reaction at room temperature. A library of electronically diverse aryl bromides and arylboronic acids underwent the cross‐coupling reaction at very good rates in aqueous solvent. The reusability of the catalyst was also examined and it was found to be effective up to three catalytic cycles. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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A new and efficient cyclization reaction has been developed to synthesize cyclic α,α‐disubstituted β‐amino esters via iron‐catalyzed intramolecular aminomethyloxygenative cyclization of diazo compounds with N,O‐aminal under mild reaction conditions. A broad range of hydroxy‐α‐diazoesters with different substituents and various N,O‐aminals were compatible with this protocol, affording the corresponding α,α‐disubstituted β‐amino esters bearing a five‐ to eight‐membered oxacycle in good yields. 相似文献
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Hai‐tao Zhang Prof. Dr. Xiao‐dong Fan Prof. Dr. Wei Tian Rong‐tian Suo Zhen Yang Yang Bai Wan‐bin Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(13):5000-5008
The controlled secondary self‐assembly of amphiphilic molecules in solution is theoretically and practically significant in amphiphilic molecular applications. An amphiphilic β‐cyclodextrin (β‐CD) dimer, namely LA‐(CD)2, has been synthesized, wherein one lithocholic acid (LA) unit is hydrophobic and two β‐CD units are hydrophilic. In an aqueous solution at room temperature, LA‐(CD)2 self‐assembles into spherical micelles without ultrasonication. The primary micelles dissociates and then secondarily form self‐assemblies with branched structures under ultrasonication. The branched aggregates revert to primary micelles at high temperature. The ultrasound‐driven secondary self‐assembly is confirmed by transmission electron microscopy, dynamic light scattering, 1H NMR spectroscopy, and Cu2+‐responsive experiments. Furthermore, 2D NOESY NMR and UV/Vis spectroscopy results indicate that the formation of the primary micelles is driven by hydrophilic–hydrophobic interactions, whereas host–guest interactions promote the formation of the secondary assemblies. Additionally, ultrasonication is shown to be able to effectively destroy the primary hydrophilic–hydrophobic balances while enhancing the host–guest interaction between the LA and β‐CD moieties at room temperature. 相似文献