共查询到20条相似文献,搜索用时 15 毫秒
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报道了2-(4′-正烷基苯)-4,6-二羟基-5-烷基嘧啶类衍生物的电子轰击源(EI)的质谱行为,通过对10种不同取代基嘧啶类衍生物的质谱研究,推测了该类化合物的质谱裂解机理。该类化合物离子的主要特征是均有较强的分子离子;其基峰离子是由于嘧啶环烷基的β位处断裂,形成基峰离子[R2C6H4C4N2(OH)2CH2] ;碎裂离子主要是由于嘧啶环断裂所致,从而形成[R2C6H4C2N2OH] 、[R2C6H4CN] ·、[R2C6H4C] 等一系列特征离子。 相似文献
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以右旋CB-15为原料,通过水解反应制备了一个含有手性基团的联苯甲酸型化合物,用红外光谱(FTIR)、核磁共振(1HNMR)和元素分析(EA)对其化学结构进行了确认。结合差示扫描量热(DSC)、偏光显微镜(POM)和变温红外光谱等对它的二聚体的热稳定性进行了研究。结果表明,此化合物仅有胆甾相,且与非手性酸类似,当它处于熔融态时,它的红外谱图上会出现代表游离态的羰基和羟基存在的吸收峰,且它们随着温度的升高而增大。结合DSC数据可知,这意味着此手性酸羧在固态时绝大部分是以二聚体的形式存在的,但当它受热熔融后,它的二聚体则会发生部分分解,并且随着温度的升高,分解量逐渐增加。 相似文献
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4-甲氧基苯酚4′-正烷氧基-2′,3′,5′,6′-四氟联苯甲酸酯的合成及相变研究 总被引:1,自引:0,他引:1
本文报道了4—甲氧基苯酚4′—正烷氧基—2′,3′,5′,6′—四氟联苯甲酸酯的合成方法及相变性质,并讨论了此类液晶的结构和性质的关系。 相似文献
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Tobias Glaser Sebastian Beck Bernd Lunkenheimer Daniela Donhauser Andreas Köhn Michael Kröger Annemarie Pucci 《Organic Electronics》2013,14(2):575-583
Electrochemical doping produces clear changes in the vibrational spectra of organic semiconductors as we show here for the system molybdenum oxide (MoO3) doped into the charge transport material 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP). Based on density-functional theory (DFT) calculations of vibrational spectra, the new spectral features can be attributed to the CBP cation that forms as a result of electron transfer from CBP to MoO3. The intensity of the new vibrational lines is a direct measure for the probability of charge transfer. MoO3 agglomerating within the CBP matrix limits the active interface area between the two species. The appearance of a broad electronic transition in the infrared range indicates a new electronic structure at the interface compared to the individual components. The intensity of this electronic excitation serves as a measure for the interface area indicating a linear increase with MoO3 concentration. Deposition onto cooled substrates results in smaller agglomerates, and thus yields a higher efficiency. 相似文献
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丁烯类液晶具有黏度小、熔点低、清亮点高、低温稳定性良好的优点,对改进混晶的性能有着显著作用,是一类具有广阔前景的液晶单体。本文经过对接、酰化、酯化反应得到2-氟-4-溴-1-乙酸乙酯基联苯,与丙基苯硼酸偶联、还原、氯代得到4-氯甲基-2′-氟-4″丙基-[1,1′,4′1″]三联苯,再与3-氯丙烯的格氏试剂偶联,共7步反应得到目标产物4-(3-烯)正丁基-2′氟-4″丙基-[1,1′,4′1″]三联苯,总收率为21.7%。最后对化合物进行了IR、H1 NMR、GC-MS表征。 相似文献
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目的:通过DNA甲基化转移酶抑制剂5-氮杂-2′-脱氧胞苷(5-Aza-CdR)对人子宫内膜样癌JEC细胞(中分化)中p57kip2基因启动子区去甲基化干预,研究5-Aza-CdR对JEC细胞生长抑制及形态改变的影响。方法:Ⅰ.用亚硫酸氢盐测序PCR (BSP)法检测不同浓度5-Aza-CdR干预后JEC细胞中p57kip2基因启动子区甲基化状态。Ⅱ.将实验组分为12.5μmol·L-1组、12.5μmol·L-1组(48h换液时追加一次5-Aza-CdR),对照组不加任何浓度的5-Aza-CdR:(1)干预24 h、72 h,倒置显微镜下观察各组细胞的生长情况。(2)干预72 h,电镜观察各组细胞的超微结构改变情况。结果:Ⅰ. JEC细胞中p57kip2基因启动子区甲基化水平:未加药组(0μmol·L-1)p57kip2基因启动子区呈高甲基化状态(88.1%),12.5μmol·L-1组总体甲基化率最低(76.2%)。Ⅱ. JEC细胞的生长情况及形态改变情况:(1)光镜:对照组JEC细胞呈多角形或不规则形,梁索状、巢团状、小巢状或散在分布,局部形成微腺泡样结构。随着培养时间的延长,细胞密度逐渐增加,微腺泡样结构更加明显。与对照组比较,干预24 h后,两实验组细胞密度均有所减少;干预72 h后,12.5μmol·L-1组细胞密度仅比对照组略有减少,12.5μmol·L-1组细胞密度比对照组明显稀少。(2)电镜:对照组JEC细胞呈不规则形,表面可见短小的微绒毛;胞质内可见线粒体、粗面内质网、分泌泡、脂滴和自噬溶酶体等结构;胞核不规则形,以常染色质为主,可见篮网状核仁,偶见核分裂像及凋亡的细胞。干预72 h后,两实验组细胞表面微绒毛均较对照组增多,胞质内分泌泡、自噬溶酶体增多,扩张的内质网腔内充满合成的蛋白质,未见线粒体肿胀,12.5μmol·L-1组比12.5μmol·L-1组的结构改变更明显。结论:5-Aza-CdR可下调人子宫内膜样癌JEC细胞中抑癌基因p57kip2启动子区甲基化水平,从而发挥其抑制JEC细胞生长与增殖的作用,还可使细胞向较好的分化方向转化;浓度为12.5μmol·L-1的5-Aza-CdR对JEC细胞不具备细胞毒性作用,追加用药比单纯一次用药对JEC细胞生长与增殖的抑制的效果更好。 相似文献
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以4-羟基联苯为原料,经酰化、氨解、脱水三步反应合成了液晶材料重要中间体4-羟基-4′-氰基联苯,总收率达51.8%,其结构经核磁共振、质谱、红外光谱等确证,HPLC含量在99%以上。 相似文献
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合成了双—(反—4—烷基环己烷羧酸)—2,3—二氯—1,4—苯二酯,烷基分别为n-C6H13、n-C7H15、n-C8H17。测定了这些化合物的液晶相变温度,并通过磁场法测定了介电各向异性,Δε均为负值。 相似文献
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C篇1.来稿摘要1.1 各主管部门提供的邻信道间隔的资料复述于下面的§2。国家名字用国际频率表前言中表1所示的适当符号来代替。1.2 德意志联邦共和国阐述了公众的和专用的陆地移动业务的频率指配和协调方法。所阐述的频率规划方法基于这样的假设即在扩展的网络中,为了很好的节约频率,使用相同频率的台间距离(共信道间距)应 相似文献
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A new electroluminescent material tris-[5-choloro-8-hydroxyquinoline] aluminum has been synthesized and characterized. Solution of this material Al(5-Clq)3 in toluene showed absorption maxima at 385 nm which was attributed to the moderate energy (π-π*) transitions of the aromatic rings. The photoluminescence spectrum of Al(5-Clq)3 in toluene solution showed a peak at 522 nm. This material shows thermal stability up to 400 ℃. The structure of the device is ITO/0.4 wt%F4-TCNQ doped α-NPD (35 nm) / Al(5-Clq)3(30 nm)/ BCP (6 nm)/ Alq3(30 nm)/ LiF (1 nm)/Al(150 nm). This device exhibited a luminescence peak at 585 nm (CIE coordinates, x= 0.39, y= 0.50). The maximum luminescence of the device was 920 Cd/m2 at 25 V. The maximum current efficiency of OLED was 0.27 Cd/A at 20 V and maximum power efficiency was 0.04 lm/W at 18 V. 相似文献
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偶氮苯及其衍生物是性能良好的介晶基团,含偶氮苯的分子有广泛的用途。文章报道了ω-(4-甲氧基-4′-偶氮苯氧)溴代烷(ZOn,亚甲基数n为2~6)的制备,所合成化合物的结构由红外光谱分析(IR)和核磁共振(1HNMR)测试确定。示差扫描量热(DSC)测试及偏光显微镜(POM)观察显示,产物ZO2未表现出液晶性,ZO3显双向液晶性,呈近晶相;ZO4、ZO5、ZO6呈单向液晶性,为向列相。它们的织构随n的增大而逐渐改善,ZO6的偏光织构最完善。 相似文献
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Photoelectric cells based on titanium dioxide and di-(isothiocyanate)-bis-(2,2′-bipyridyl-4,4′-dicarboxylate)ruthenium(II) with titanium and gold electrodes are fabricated. An analysis of the dark and light current-voltage characteristics shows that the electrode material affects the main parameters of the solar cells: the open-circuit voltage, short-circuit current, and efficiency. 相似文献
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第三届亚太地区微波会议(APMC′90)将于1990年9月18-21日存日本东京召开。本届会议由日本电子、信息和通讯工程师协会(IEICE)主持并由IEEE MTT-S东京分会协办(拟与URSI合作,正在协商中)。征文将主要涉及如下领域: 相似文献
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A novel cathodically coloring viologen electrochrome: 1,1′-bis(2-(1H-indol-3-yl)ethyl)-4,4′-bipyridinium diperchlorate (IEV), comprising of a 4,4′-bipyridyl core, sandwiched between two indole moieties, was synthesized using 3-(2-bromoethyl)-indole. An electrochromic device (ECD) was assembled using an electrolyte containing an imidazolium imide ionic liquid and characterized by a large electrical conductivity, thermal stability upto 150 °C, and an electrochemical potential stability range of ∼3.6 V. The IEV viologen was dissolved in the electrolyte and Prussian blue was used as the anodic electrochrome. The indole moieties of the IEV2+ salt owing to their electron donating tendency can act like bleaching agents and bleach the viologen faster (IEV+ → IEV2+) and this hypothesis was used for the improved write–erase efficiency of the device. The device switched between colorless and dark violet–blue hues under applied potentials of ±1.5 V. A large transmission modulation (52%, λ = 605 nm), a high electrochromic coloring efficiency of 533 cm2 C−1 at 605 nm and switching times of ∼2 s and good stability during 2000 cycles were reported herein. The electrochemical activity of the ECD improved when it was maintained at an elevated temperature of 70 °C, with no sign of thermal degradation. Furthermore, we also present the ability of this new viologen to function as an excellent redox mediator as we achieved an 86% enhancement in the power conversion efficiency of a solution processed solar cell, by its’ addition in the electrolyte. Our studies demonstrate this new viologen to be a highly versatile electroactive material which can be useful for both electrochromics and photovoltaics. 相似文献