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排序方式: 共有205条查询结果,搜索用时 15 毫秒
1.
利用Wittig反应将高荧光量子产率的蒽基团通过双键连接在四硫富瓦烯单元上,合成了二元共轭体系化合物TTFan.在氧化作用的控制下,四硫富瓦烯单元的给电子能力降低,TTFan的荧光发射强度增大至原来的十几倍,实现了荧光的“off-on”过程.  相似文献   
2.
粗蒽中蒽、菲、咔唑的分离与精制技术进展   总被引:2,自引:0,他引:2  
综述了从粗蒽中分离和精制蒽、菲、咔唑的技术进展,介绍了物理分离法、化学分离法和复合法,并对各种方法进行了评述。结果表明,复合法因其流程简单、投资低和元环境污染等,具有推广价值。  相似文献   
3.
Isocyanoaminoarenes (ICAAr-s) are a novel and versatile group of solvatochromic fluorophores. Despite their versatile applicability, such as antifungals, cancer drugs and analytical probes, they still represent a mostly unchartered territory among intramolecular charge-transfer (ICT) dyes. The current paper describes the preparation and detailed optical study of novel 1-isocyano-5-aminoanthrace (ICAA) and its N-methylated derivatives along with the starting 1,5-diaminoanthracene. The conversion of one of the amino groups of the diamine into an isocyano group significantly increased the polar character of the dyes, which resulted in a significant 50–70 nm (2077–2609 cm−1) redshift of the emission maximum and a broadened solvatochromic range. The fluorescence quantum yield of ICAAs is strongly influenced by the polarity of the solvent. The starting anthracene-diamine is highly fluorescent in every solvent (√f = 12–53%), while the isocyano derivatives are practically nonfluorescent in solvents more polar than dioxane. This phenomenon implies the potential application of ICAAs to probe the polarity of the medium and is favorable in practical applications, such as cell-staining, resulting in a reduced background fluorescence. The ICT character of the emission states of ICAAs are in good agreement with the computational findings presented in TD-DFT calculations and molecular electrostatic potential (MESP) isosurfaces.  相似文献   
4.
Solvent crystallization is the main method used for preparing anthracene and carbazole from the crude anthracene. The key to the optimization of this method is improving the solubility selectivity of the solvent by means of solvent modulating and process optimization. In this study, the solubility of anthracene, phenanthrene, and carbazole in xylene, dimethylformamide (DMF), DMF with amine/amide, isopropanolamine, and chlorobenzene is examined and the solid‐liquid ternary anthracene–carbazole–DMF/(DMF+19.96% isopropanolamine) system phase diagram is determined and applied in the solvent crystallization process. The results showed that the solubility selectivity of xylene increases with increased temperature. Also, selectivity increases with an increase of the amount of isopropanolamine in the mixture of DMF and isopropanolamine, while decreases with increased temperature. Through multiple washings of crude anthracene with xylene, DMF+19.96% isopropanolamine, and chlorobenzene, it was possible to obtain anthracene and carbazole of purity higher than 98 wt %. © 2013 American Institute of Chemical Engineers AIChE J, 60: 275–281, 2014  相似文献   
5.
Three mechanisms have been proposed to explain the carcinogenic activities of polycyclic aromatic hydrocarbons (PAHs). On the basis of the nature of the active metabolites involved, they may be termed: the diol epoxide mechanism, the quinone mechanism, and the radical-cation mechanism. In connection with studies to evaluate the relative importance of these pathways, we required practical methods for the syntheses of the active PAH metabolites involved. We now report efficient new synthesis of the o-quinones of benzo[a]pyrene (BPQ), 7,12-dimethylbenz[a]anthracene (DMBAQ), and benz[a]anthracene (BAQ). These quinones are convenient synthetic precursors of the related o-catechols, trans-dihydrodiols, and diol epoxides, as well as the stable adducts of the o-quinones with 2-deoxyadenosine and 2′-deoxyguanosine.  相似文献   
6.
Experiments were designed to investigate how the route of exposure to polycyclic aromatic hydrocarbons (PAHs) in mice and rats affects the induction of cytogenetic end points and DNA adduction. Both mice and rats were exposed to 100 mg/kg of benz[ a ]anthracene (B[ a ]A), benzo[ b ]fluoranthene (B[ b ]F), benzo[ a ]pyrene (B[ a ]P), or chrysene (Chr) by gavage or by intraperitoneal injection (i.p.). Peripheral blood was removed by cardiac puncture 7 days after PAH administration. Blood samples were analyzed in parallel for sister chromatid exchange (SCE) frequency, the frequency of micronuclei in cytochalasin B-induced binucleate cells (MN bn ), and DNA adduction using 32P-postlabeling. The i.p. route of exposure produced both the highest levels of cytogenetic damage and DNA adducts for each PAH. The mouse was more sensitive than the rat to PAH exposure as measured by SCE induction and the total amount of DNA adducts/ w g DNA.  相似文献   
7.
PAHs代谢物对PAHs生物降解的影响作用   总被引:1,自引:0,他引:1  
分别研究了芽胞杆菌CN2降解蒽产生的代谢物对蒽生物降解的影响和菲产生的代谢物对菲生物降解的影响.试验结果表明:(1)外加蒽(或菲)代谢物,对蒽(或菲)的降解均表现出促进作用.蒽156 h累计去除率可提高3.07%~6.10%,菲60 h累计去除率可提高13.14%~30.35%.(2)在芽胞杆菌CN2作用下,蒽(或菲)生物降解过程能够用一级动力学方程式较准确地描述,外加代谢物可以增大降解反应表观速率常数k值;从不同时段内蒽(或菲)的降解速率看,反应初期0~2 h内,外加代谢物对蒽(或菲)的降解速率提高最为明显,对蒽可提高0.281~1.20 mg/L·h,对菲可提高0.570~1.13 mg/L·h.(3)外加代谢物对蒽(或菲)降解液的pH值有缓冲作用,使降解液的pH值随降解时间下降趋势减缓.  相似文献   
8.
采用反应分子动力学模拟方法ReaxFF模拟蒽热生焦初期的反应过程,推测得到蒽缩合生成四聚体可能的反应途径。蒽在热生焦初期,首先通过氢转移反应引发生成自由基?C14H9,自由基?C14H9与周围的蒽分子结合生成自由基?C28H19,?C28H19被周围的蒽分子夺去1个氢原子生成二聚物C28H18。二聚物C28H18通过氢转移反应生成自由基?C28H17,自由基?C28H17与周围的二聚物分子反应,可能生成三聚物C42H26,也可能生成四聚体自由基?C56H35。  相似文献   
9.
以蒽和1-十一烯烃为原料,HY型分子筛作催化剂,在微型高压釜中反应得到蒽的烷基化产物,通过单因素实验,考察了反应温度、反应压力、反应时间、催化剂添加量、物料配比对蒽烷基化反应的影响。结果表明:在反应温度为180 ℃,反应压力为3.0 MPa,HY型分子筛质量分数为5%,蒽/1-十一烯烃(摩尔比)为0.77的优化条件下,蒽的转化率达到85.08%。气相色谱-质谱联用和傅里叶变换红外光谱分析结果表明,多种烷基化蒽的选择性为48.93%,蒽与1-十一烯烃的反应为多种反应同时进行的复杂烷基化反应。  相似文献   
10.
A series of sulfonated polyaniline/derivatized polyaniline nanocomposites was chemically synthesized in the presence of anthracene and naphthalene sulfonic acids. UV-vis and FTIR results indicated the emergence of new bands at 420 and 700 nm and 1100 cm?1 in their spectra, respectively, meaning the dopant/polymer intercalations involved electronic interactions between dopant/polymer sub-lattices. The electroactive composites displayed moderately fast electrode kinetics. A composite-based biosensor for hydrogen peroxide reached a steady state current of 9.2 and 5.3 µA, and when fine-tuned for diazinon detection gave % inhibitions to be 41 and 81% for the polyaniline and poly-o-methoxyaniline biosensors, respectively.  相似文献   
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