共查询到20条相似文献,搜索用时 15 毫秒
1.
In this paper, a copolymer of carbazole (Cz) and 2,2′:5′,2″-terthiophene (TTh) was electropolymerized in 0.1 M sodium perchlorate (NaClO4)/acetonitrile (CH3CN) on glassy carbon electrode. The optimum conditions of resulting homopolymers of Cz, TTh and copolymer of Cz and TTh in the initial feed ratio of [Cz]0/[TTh]0 = 1/10 were characterized by cyclic voltammetry, Fourier-transform infrared-attenuated total reflectance, scanning electron microscopy, energy dispersive X-ray analysis, and electrochemical impedance spectroscopy. Morphological analysis of copolymer shows that a micro-spherical and web-like morphology was formed for copolymer at different initial feed ratios of [Cz]0/[TTh]0 = 1/2, 1/5 and 1/10. The capacitive behavior of the modified electrodes was defined via Nyquist, Bode-magnitude, and Bode-phase plots. The highest low-frequency capacitance (C LF) was obtained as 4.11 mFcm?2 in the initial feed ratio of [Cz]0/[TTh]0 = 1/10. Double-layer capacitance (C dl) and phase angles (θ) were obtained for homopolymer and copolymer systems. The highest C dl was obtained as 2.01 mFcm?2 for the copolymer in the initial feed ratio of [Cz]0/[TTh]0 = 1/2. The highest phase angle of copolymer was obtained as θ = ~75° in the initial feed ratio of [Cz]0/[TTh]0 = 1/1. These capacitance results confirmed that films of copolymer Cz/TTh are promising materials for micro-capacitor applications. 相似文献
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近年来,由于α′-sialon的高硬度和良好的抗热震性,使α′和α′-β′复相sialon陶瓷的研究引人注目。对α′-sialon平面相关系的测定已经表明:α′-sialon的单相区起始于纯氮化物一端向氧化铝方向延伸,在α′-simon和β′-sialon之间存有一个α′-β′两相区。这个两相区提供了制备两相陶瓷的可能性。由于α′和β′组成的差别甚微,因此在烧成过程中,当加有适当的添加剂时,α′和β′之间的相变很容易发生。故在制备α′-sialon划α′-β′-sialon陶瓷时,控制相变极为重要,为此有必要了解它们的反应机理。 本文描述了在不同烧成环境下α′和α′-β′-sialon的反应机理,所采用的组成是含Y的α′-sialon,并分别添加和不加La_2O_3作为助烧结剂。本文还着重研究了烧成环境对α′和β′相互转变的影响,以及La_2O_3对致密化和α′-sialon形成的作用。 相似文献
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Dr. Benedikt Schwarze Sanja Jelača Linda Welcke Prof. Dr. Danijela Maksimović-Ivanić Prof. Dr. Sanja Mijatović Prof. Dr. Dr. h.c. mult. Evamarie Hey-Hawkins 《ChemMedChem》2019,14(24):2075-2083
Investigations on the antitumor activity of metallacarboranes are sparse in the literature and limited to a handful of ruthena- and molybdacarboranes. In this study, the molybdacarborane fragment [3-(CO)2-closo-3,1,2-MoC2B9H11] was combined with a vector molecule, inspired by the well-known drug tamoxifen or 4,4′-dihydroxytamoxifen (TAM-diOH). The molybdacarborane derivative [3,3-{4-[1,1-bis(4-hydroxyphenyl)but-1-en-2-yl]-2,2′-bipyridine-κ2N,N′}-3-(CO)2-closo-3,1,2-MoC2B9H11] ( 10 ), as well as the ligand itself 4-[1,1-bis(4-hydroxyphenyl)but-1-en-2-yl]-2,2′-bipyridine ( 6 ) showed cytotoxic activities in the low micromolar range against breast adenocarcinoma (MDA-MB-231, MDA-MB-361 and MCF-7), human glioblastoma (LN-229) and human glioma (U-251) cell lines. In addition, compounds 6 and 10 were found to induce senescence and cytodestructive autophagy, lower ROS/RNS levels, but only the molybdacarborane 10 induced a strong increase of nitric oxide (NO) concentration in the MCF-7 cells. 相似文献
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Dr. Katrin Rosenthal Martin Becker Jascha Rolf Regine Siedentop Dr. Michael Hillen Prof. Dr. Markus Nett Prof. Dr. Stephan Lütz 《Chembiochem : a European journal of chemical biology》2020,21(22):3225-3228
Cyclic GMP-AMP synthase (cGAS) is a cytosolic DNA sensor that catalyzes the synthesis of the cyclic GMP-AMP dinucleotide 2′3′-cGAMP. 2′3′-cGAMP functions as inducer for the production of type I interferons. Derivatives of this important second messenger are highly valuable for pharmaceutical applications. However, the production of these analogues requires complex, multistep syntheses. Herein, human cGAS is shown to react with a series of unnatural nucleotides, thus leading to novel cyclic dinucleotides. Most substrate derivatives with modifications at the nucleobase, ribose, and the α-thio phosphate were accepted. These results demonstrate the catalytic promiscuity of human cGAS and its utility for the biocatalytic synthesis of cyclic dinucleotide derivatives. 相似文献
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啤酒厂每生产100t啤酒就会得到含水分75%~80%的剩余酵母泥约1.5t,可制成含水8.5%~10%的干酵母约0.35t。这些酵母富含蛋白质、核酸、维生素、矿物质等多种营养成分,目前主要用于饲料工业,利用率很低。啤酒酵母的核酸(主要为核糖核酸RNA... 相似文献
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Three allelochemicals from rye or its breakdown products were evaluated for activity on garden cress (Lepidum sativum L.), barnyardgrass [Echinochloa crus-galli (L.) Beauv.], cucumber (Cucumis sativus L.), and snap bean (Phaseolus vulgaris L.). 2,4-Dihydroxy-1,4(2H)-benzoxazin-3-one (DIBOA), 2(3H)-benzoxazolinone (BOA), and 2,2-oxo-1,1-azobenzene (AZOB) were all applied singly at 50, 100, and 200 ppm and in two- and three-way combinations each at 50 and 100 ppm. AZOB at 100 and 200 ppm produced 38–49% more inhibition than DIBOA, while combinations of BOA/ DIBOA, which contained AZOB at 100 ppm had 54–90% more inhibition when compared to DIBOA/BOA combinations. All combinations were slightly antagonistic to barnyardgrass, while several combinations caused a synergistic response to garden cress germination and growth. Cucumbers and snap beans exhibited both types of responses, depending on the allelochemical combination and application rate. The plant-produced benzoxazinones were more inhibitory to crops than weeds. Therefore, improved herbicidal selectivity would be expected if there were rapid transformation of the benzoxazinones to the microbially produced AZOB. 相似文献
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《分离科学与技术》2012,47(11-12):1959-1970
Abstract Inosine- and uridine-5′-diphosphates can be purified by ion-exchange chromatography utilizing a new ion-exchange method where Type 1 ion-exchange resins and the absorbed nucleoside polyphosphates are changed to the basic form by rinsing the column with dilute sodium hydroxide and subsequently eluting with dilute hydrochloric acid and sodium chloride. 相似文献
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Dr. Pierre-Yves Geant Dr. Malika Kaci Dr. Jean-Pierre Uttaro Prof. Christian Périgaud Prof. Christophe Mathé 《ChemMedChem》2019,14(5):522-526
The synthesis and anti-HIV evaluation of hitherto unknown 3′-fluoro-5′-norcarbocyclic nucleoside phosphonates bearing adenine with modifications at the 4′ position (ethynyl, vinyl, ethyl, hydroxymethyl) is described. One of the synthesized compounds was found to be an inhibitor of HIV-1 replication, but with moderate efficiency relative to (R)-9-(2-phosphonylmethoxypropyl)adenine ((R)-PMPA, tenofovir), with no concomitant cytotoxicity. 相似文献
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《Reactive and Functional Polymers》2004,58(2):111-115
Aromatic coupling copolymerization of 5,5′-bis(4-chlorobenzoyl)-2,2′-dimethoxybiphenyl (1) and 5,5′-bis(3-chlorobenzoyl)-2,2′-dimethoxybiphenyl (2) has successfully afforded higher-molecular-weight polyketones than either of the corresponding homopolymerizations. The wholly aromatic copolyketones thus obtained have highly amorphous nature with high glass transition temperatures (Tg). 相似文献
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Edwin C. Constable Catherine E. Housecroft Jason R. Price Luca Schweighauser Jennifer A. Zampese 《Inorganic chemistry communications》2010,13(4):495-497
The first example of a copper-catalysed [2 + 3] cycloaddition reaction of a coordinated 4′-azido-2,2′:6′,2″-terpyridine ligand is reported and the solid state structures of the precursor and product are described. 相似文献
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Two of the majorNuphar alkaloids, nupharolutine and 6,6-dihydroxythiobinupharidine, were isolated from the aquatic perennial herbNuphar lutea (L.) Sibth. & Sm., yellow water lily. In a lettuce seedling bioassay of the two pure compounds, the former was inactive and the latter was highly inhibitory of radicle elongation at concentrations greater than 2 ppm. Structures and stereochemistry of the two compounds were confirmed by DEPT,1H-1H COSY,1H-13C COSY, and1H-1H NOESY experiments. 相似文献
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《Journal of Sulfur Chemistry》2013,34(4):275-282
Atropisomers of 2,2′-bithiophene-5-tetrahydroisoquinoline, S -8, R -8, and 2,2′-bithiophene-5,5′-tetrahydroisoquinoline, (S,S)-11, (R,S)-11, (R,R)-11, analogs of michellamines have been synthesized in low yield under Stille coupling conditions (Pd0-mediated cross coupling reactions) of stannanes 1 or 2 with non-racemic bromotetrahydroisoquinoline 6. The use of non-racemic iodotetrahydroisoquinoline 7 instead of 6 significantly improves the efficiency of the coupling, affording the atropisomers in moderate yields. 相似文献
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Summary The electrochemical properties of poly(4,4-diphenylamine methylenes) and poly(4,4-diphenylimine methines) were investigated by cyclic voltammetry. A dehydrogenation reaction occured when poly(4,4-diphenylamine methylenes) underwent a electrochemical reaction and transformed to poly(4,4-diphenylimine methines). The fully oxidized poly(4,4-diphenylimine methines) had the electrochemical band gaps of 1.60–1.72 eV, which were found to significantly smaller than those of the fully reduced poly(4,4-diphenylamine methylenes). 相似文献
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Summary The synthesis and Ni(0) catalyzed homocoupling polymerization of 4,4-bis[5-(trifluoromethanesulfonyloxy)-2-biphenylyl]-1, 1-binaphthyl (9) are described. This polymerization reaction produces a soluble polyarylene containing alternating 4,4-(1,1-binaphthyl) and 4,4-(3,3-diphenyl)biphenyl structural units. 相似文献
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《Inorganic chemistry communications》1999,2(9):403-406
The synthesis of key monomers for use in the synthesis of poly-1,1′-ferrocenylacetylene (polyferrocenylethyne, PFcE) has been achieved. The monomers are 1′-bromoferrocenylethyne and 1′-iodoferrocenylethyne, which were prepared from 1,1′-dibromo- and 1,1′-diiodoferrocene, respectively, in a simple two-step synthesis. This synthesis complements the pre-existing more elaborate methodology. 相似文献