共查询到20条相似文献,搜索用时 203 毫秒
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6-甲基-[1,3]二氧戊环并[4,5-g]喹啉-7-甲酸乙酯(1)与N-溴代丁二酰亚胺(NBS)在150W白炽灯照射的条件下有效的发生自由基溴化反应,以较好的收率(75%)得到想要的单溴化产品6-(溴甲基)-[1,3]二氧戊环并[4,5-g]喹啉-7-甲酸乙酯(2)。本文所开发的自由基溴化方法与文献相比,单溴化产品的收率提高了46%。另外,该溴化反应中所生成的少量副产品也进行了分离提纯,其结构经波谱分析证实为9-溴-6-甲基-[1,3]二氧戊环并[4,5-g]喹啉-7-甲酸乙酯(3)。 相似文献
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以邻硝基苯甲醛为起始原料,经还原和氨基保护合成2-乙酰胺基苯甲醛(1)。应用环境友好的聚乙二醇-400为溶剂,以N-卤代丁二酰亚胺为卤代试剂对化合物2-乙酰胺基苯甲醛(1)进行卤代,制备了5-溴(氯)-2-乙酰胺基苯甲醛(2a,2b)。在三甲基氯硅烷(TMSCl)催化作用下,5-溴(氯)-2-乙酰胺基苯甲醛(2a,2b)与4-氯乙酰乙酸乙酯发生Friedlnder缩合反应,合成目标产物6-溴(氯)-2-氯甲基-3-喹啉甲酸乙酯(3a,3b)。其中2a,2b,3a,3b的结构经IR、1H NMR、13C NMR、MS得以确定。 相似文献
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2-(取代哌嗪-1-甲基)-3-喹啉甲酸乙酯及其衍生物的合成、 表征及晶体结构 总被引:1,自引:0,他引:1
以邻硝基苯甲醛为起始原料, 经还原、Friedländer 缩合反应合成2-甲基-3-喹啉甲酸乙酯(2), 2经N-溴代丁二酰亚胺(NBS)溴代得到化合物3, 3再与N-取代哌嗪5a~5p 发生SN2亲核取代反应, 合成一系列2-(取代哌嗪-1-甲基)-3-喹啉甲酸乙酯及其衍生物6a~6p. 它们的结构通过元素分析, IR, 1H NMR, 13C NMR和MS进行了鉴定和表征, 并用X射线衍射法测定了化合物6n的晶体结构. 相似文献
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麦芽酚及麦芽酚-3-O-β-D-葡萄糖甙的合成 总被引:1,自引:0,他引:1
以乙酰丙酮(1)为原料,经溴代、酯化反应得到3-苯甲酰氧基-2,4-戊二酮(2),2与甲酸乙酯缩合、脱水闭环、酯水解得麦芽酚(3),总收率50.4%。3与a一溴代四乙酰化葡萄糖(4)经糖甙化、脱乙酰基得麦芽酚-3-O-β-D-葡萄糖甙(5),收率60.8%,IR,^1H NMR和^13C NMR确证5的葡萄糖为β-构型。中间产物2无须纯化,可实现“一锅”反应合成3。 相似文献
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Haijian Yu Qiaohui Wang Prof. Youming Wang Prof. Haibing Song Prof. Zhenghong Zhou Prof. Chuchi Tang 《化学:亚洲杂志》2013,8(11):2859-2863
A highly diastereo‐ and enantioselective cyclopropanation of β,γ‐unsaturated α‐ketoesters with bromonitromethane has been successfully developed through a domino Michael‐addition/intramolecular‐alkylation strategy. Acceptable yields (up to 89 %) and enantioselectivities (up to 96 % ee) have been obtained. 相似文献
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T. V. Gubanova E. I. Frolov I. K. Garkushin 《Russian Journal of Inorganic Chemistry》2009,54(5):792-796
Phase equilibria in the LiF-LiBr-LiVO3 and LiBr-Li2SO4-LiVO3 systems have been investigated by differential thermal analysis. Eutectic compositions have been revealed (mol %). In the LiF-LiBr-LiVO3 system, 16.8% LiF, 52.0% LiBr, 31.2% LiVO3 with a melting point of 428°C; in the LiBr-Li2SO4-LiVO3 system, 52.0% LiBr, 38.0% LiVO3, 10.0% Li2SO4 with a melting point of 444°C. Crystallization fields of the phases have been demarcated. 相似文献
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Zaira Batool M. Raffi M. Zakria Rana I. Shakoor R. Rashid Mazhar Mehmood Muhammad Aslam Mirza 《Journal of Cluster Science》2017,28(4):1857-1870
In this research work, crystalline structure, phase transformation, morphology and mean size of titanium dioxide (TiO2) electrospun nanofibers have been tailored by loading with 2.5, 5.0 and 7.5 wt.% of silver (Ag) which was followed by calcination. The as prepared non woven mats of nanofibers were calcinated at 500 °C to allow the reaction moieties to leave the TiO2 matrix and subsequently formation of Ag clusters. The effect of Ag loading and calcination on the transformation of microstructure of these electrospun nanofibers have been characterized by XRD, FESEM, FT-IR and Raman spectroscopy (RS). The mean diameter of Ag loaded nanofibers has been found to decrease upon calcination which was estimated to 70 nm whereas length was in the order of mm range. XRD and RS results have strongly supported the transformation of crystalline phase from rutile (A) to anatase (R) above 2.5 wt.% of Ag loading in TiO2 after calcination. The roughness on the outer surfaces of these nanofibers has been observed to increase with the Ag loading consequent to calcination, which has been attributed to the formation Ag nanoparticles that were found adsorbed at the surfaces. An interesting finding of this study is the existence of 1D nanofibers’ structure even at higher (7.5 wt.%) Ag loading, as observed by the SEM micrographs. 相似文献
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《化学:亚洲杂志》2017,12(17):2299-2303
Aromatic difluoroboronated β‐diketone ( BF2DK ) derivatives are a widely known class of luminescent organic materials that exhibit high photoluminescent quantum efficiency and unique aggregation‐dependent fluorescence behavior. However, there have been only a few reports on their use in solid‐state electronic devices, such as organic light‐emitting devices (OLEDs). Herein, we investigated the solid‐state properties and OLED performance of a series of π‐extended BF2DK derivatives that have previously been shown to exhibit intense fluorescence in the solution state. The BF2DK derivatives formed exciplexes with a carbazole derivative and exhibited thermally activated delayed fluorescence (TADF) behavior to give orange electroluminescence with a peak external quantum efficiency of 10 % that apparently exceeds the theoretical efficiency limit of conventional fluorescent OLEDs (7.5 %), assuming a light out‐coupling factor of 30 %. 相似文献
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Highly Efficient Near‐Infrared Delayed Fluorescence Organic Light Emitting Diodes Using a Phenanthrene‐Based Charge‐Transfer Compound
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Shipan Wang Xianju Yan Zong Cheng Prof. Dr. Hongyu Zhang Prof. Dr. Yu Liu Prof. Dr. Yue Wang 《Angewandte Chemie (International ed. in English)》2015,54(44):13068-13072
Significant efforts have been made to develop high‐efficiency organic light‐emitting diodes (OLEDs) employing thermally activated delayed fluorescence (TADF) emitters with blue, green, yellow, and orange–red colors. However, efficient TADF materials with colors ranging from red, to deep‐red, to near‐infrared (NIR) have been rarely reported owing to the difficulty in molecular design. Herein, we report the first NIR TADF molecule TPA‐DCPP (TPA=triphenylamine; DCPP=2,3‐dicyanopyrazino phenanthrene) which has a small singlet–triplet splitting (ΔEST) of 0.13 eV. Its nondoped OLED device exhibits a maximum external quantum efficiency (EQE) of 2.1 % with a Commission International de L′Éclairage (CIE) coordinate of (0.70, 0.29). Moreover, an extremely high EQE of nearly 10 % with an emission band at λ=668 nm has been achieved in the doped device, which is comparable to the most‐efficient deep‐red/NIR phosphorescent OLEDs with similar electroluminescent spectra. 相似文献
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Tetragonal lead zirconate titanate thin films on platinized silicon wafers have been prepared from chemically different precursor
solutions by chemical solution deposition. Literature known routes have been evaluated and an optimized standard process has
been developed leading to Pb(Zr0.3,Ti0.7)O3 films with a high degree of (111) orientation which consequently shows square hysteris loops with Pr values of 34 μC/cm2. Other solvents, different alkoxides of the transition metals, and different carboxylates of lead have been systematically
introduced in this standard process and their influence on the final morphological and electrical properties has been studied.
It has been found that the use of lead (II) propionate and titanium tetra n-butoxide for solution synthesis leads to a decrease of the remanent polarization of ∼50%. Furthermore the reaction atmosphere
after spinning and during the pyrolysis has been investigated. Increased ambient humidity after the spin coating process also
caused a significant deterioration of the final film properties. The findings have been explained in terms of a hindered formation
of the (111) texture promoting intermediate Pt
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Pb phase. 相似文献
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Hanfang Zhong Ping Wei Pingkai Jiang Dan Wu Genlin Wang 《Journal of Polymer Science.Polymer Physics》2007,45(13):1542-1551
Novel halogen‐free compounds [9,10‐dihydro‐9‐oxa‐10‐phosphaphanthrene‐10‐oxide/vinyl methyl dimethoxysilane/N‐β‐(aminoethyl)‐γ‐aminopropyl methyl dimethoxysilane (DOPO–VMDMS–NMDMS)] that simultaneously contain phosphorus, nitrogen, and silicon have been synthesized through the reaction of 9,10‐dihydro‐9‐oxa‐10‐phosphaphanthrene‐10‐oxide (DOPO), vinyl methyl dimethoxysilane (VMDMS), and N‐β‐(aminoethyl)‐γ‐aminopropyl methyl dimethoxysilane (NMDMS). The chemical structure and properties of DOPO–VMDMS–NMDMS have been investigated with Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, phosphorous nuclear magnetic resonance, and thermogravimetric analysis (TGA). These synthesized flame retardants have been blended with a poly[2,2‐propane‐(bisphenol) carbonate]/acrylonitrile butadiene styrene (PC/ABS) alloy. The flame‐retardant properties of these mixture samples have been estimated with the limiting oxygen index (LOI), and the thermal stability has been characterized with TGA. The LOI value of PC/ABS/DOPO–VMDMS–NMDMS is enhanced up to 27.2 vol % from 21.2 vol %, and the char yield is also improved slightly (from 12 to 17%) with 2.8 wt % phosphorus, 3.0 wt % silicon, and 0.5 wt % nitrogen (at a 30 wt % loading of DOPO–VMDMS–NMDMS). The results show that there is a synergistic effect of the elements phosphorus, silicon, and nitrogen on the flame retardance. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1542–1551, 2007 相似文献
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Phase equilibria in the LiF-LiCl-LiVO3-Li2SO4-Li2MoO4 system have been studied by differential thermal analysis. The eutectic composition has been determined as follows (mol %): LiF, 17.4; LiCl, 42.0; LiVO3, 17.4; Li2SO4, 11.6; and Li2MoO4, 11.6, with the melting temperature equal to 363°C and the enthalpy of melting equal to (284 ± 7) kJ/kg. 相似文献
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Marappan Velusamy Dr. Ying‐Chan Hsu Dr. Jiann T. Lin Prof. Dr. Che‐Wei Chang Chao‐Ping Hsu Prof. Dr. 《化学:亚洲杂志》2010,5(1):87-96
A series of donor–π–acceptor‐type organic dyes based on 1‐alkyl‐1H‐imidazole spacers 1 , 2 , 3 , 4 , 5 have been developed and characterized. The two electron donors are at positions 4 and 5 of the imidazole, while the electron‐accepting cyanoacrylic acid is incorporated at position 2 by a spacer‐containing heteroaromatic rings, such as thiophene and thiazole. Detailed investigation on the relationship between the structure, spectral and electrochemical properties, and performance of DSSC is described here. Dye‐sensitized solar cells (DSSCs) using dyes as the sensitizers exhibit good efficiencies, ranging from 3.06 to 6.35 %, which reached 42–87 % with respect to that of N719‐based device (7.33 %) fabricated and measured under similar conditions. Time‐dependent density functional theory (TDDFT) calculations have been performed on the dyes, and the results show that both electron donors can contribute to electron injection upon photo‐excitation, either directly or indirectly by internal conversion to the lowest excited state. 相似文献
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Ce-substituted BiFeO3 film (BCFO film) have been prepared by sol–gel process on F doped SnO2 (FTO)/glass substrates. The effects of Ce substitution on the structural and electrical properties have been reported. X-ray
diffraction data confirmed the R3c structure with the elimination of all secondary phases. We observed an increase in the
remnant polarization (Pr) with Ce substitution and obtained a maximum value of ∼84 μC/cm2 in 5% Ce-substituted film. The dielectric constant of the films was increased from 280 to about 420 for the BiFeO3 film and 5% Ce-substituted BCFO film, respectively and the films showed excellent dielectric loss behavior. Moreover, the
leakage current was substantially reduced by the Ce substitution. 相似文献