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991.
合成了冠醚3,3′-二甲基二苯并-18-冠-6(MDB18-C-6),并以该化合物为配体分别与镍(Ⅱ)、钯(Ⅱ)和K2(i-mnt)作用,进一步合成了配合物[K(MDB18-C-6)(CH3COCH3)]2[Ni(i-mnt)2](1)及配合物[K(MDB18-C-6)(CH3SOCH3)]2[Pd(i-mnt)2](2)。通过元素分析、红外光谱、紫外光谱、核磁共振氢谱、质谱等测试手段对其结构进行表征,用X-射线单晶衍射测定了配合物1和配合物2的晶体结构。利用紫外吸收光谱、荧光光谱和圆二色光谱等光谱分析法研究了配合物与小牛胸腺DNA(CT-DNA)的作用,结果表明两种配合物与DNA都具有相互作用,配合物主要是通过影响DNA的螺旋结构,从而引起DNA的构象变化,并且配合物2的作用性能大于配合物1。 相似文献
992.
A new method of sample preparation was developed and is reported for the first time. The approach combines in-vial filtration with dispersive solid-phase extraction (d-SPE) in a fast and convenient cleanup of QuEChERS (quick, easy, cheap, effective, rugged, and safe) extracts. The method was applied to simultaneous analysis of 42 diverse pesticides and 17 environmental contaminants, including polycyclic aromatic hydrocarbons, polychlorinated biphenyls (PCBs), and flame retardants, in shrimp as the sample matrix. Final extracts were analyzed by both low-pressure gas chromatography – triple quadrupole tandem mass spectrometry (LPGC-MS/MS), and high-performance liquid chromatography – triple quadrupole tandem mass spectrometry (HPLC-MS/MS) to provide a wide scope of analysis for targeted analytes. During method development, several different commercial sorbents for d-SPE were investigated and compared with respect to analyte recoveries. The method was validated at 10, 50, and 100 ng g−1 spiking levels (10-fold lower for PCBs), and the results for nearly all analytes were between 70 and 115% recoveries with ≤17% relative standard deviations. The method was shown to be simple, fast, and effective for multi-application analysis of chemical residues in the representative food and environmental marker matrix. 相似文献
993.
Convenient and facile syntheses of 12H-benzo[a]xanthenes from 2-tetralone and 2-hydroxyaromatic aldehydes is described. 2-Tetralone reacted with 2-hydroxyarylaldehydes to yield 12H-benzo[a]xanthenes under acidic conditions. 相似文献
994.
A. Salinas-Castillo J.F. Fernndez-Snchez A. Segura-Carretero A. Fernndez-Gutirrez 《Analytica chimica acta》2005,550(1-2):53-60
This paper presents the phosphorescence characterization of polycyclic aromatic hydrocarbons (PAHs) on solid-surface for obtaining new flow-through phosphorescence optosensors for PAHs-based on-line, immobilized onto a non-ionic resin solid support coupled to a continuous flow system and the applications for the selective determination of benzo(a)pyrene (BaP). The phosphorescent characterization of 15 PAHs, described as major pollutants by the Environmental Protection Agency (EPA) (naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, chrysene, benzo(a)anthracene, benzo(k)fluoranthene, benzo(b)fluoranthene, benzo(a)pyrene, indeno(1,2,3-cd)pyrene, benzo(g,h,i)perylene and dibenzo(a,h)anthracene) has been carried out. The experimental variables (heavy atom, deoxygenation and organic solvent in samples) for obtaining different possibilities for developing mono and multi-parameter PAH sensors and the conditions for PAH screening have been carefully studied and the experimental conditions to determination of BaP in presence of other PAHs in water samples have been optimized. 相似文献
995.
996.
997.
Barend L. van Drooge Irina NikolovaPascual Pérez Ballesta 《Journal of chromatography. A》2009,1216(18):4030-4039
Polycyclic aromatic hydrocarbons (PAHs) from ambient air particulate matter (PM) were analysed by a two-step thermal desorption (TD) injection system integrated to a gas chromatograph–mass spectrometer (GC/MS). The operational variables of the TD method were optimised and the analytical expanded uncertainties were calculated to vary from 8% to 16% over the operative concentration range (40–4000 pg). The performance of the TD method was validated by the analysis of a standard reference material and by comparison of PAH concentrations in PM samples to those obtained by a conventional liquid extraction (LE) method. The TD method reported lower uncertainties than the LE method for the analysis of similar concentrations in air. The TD method also showed advantages for shorter sampling times in comparison to 24 h for source apportionment applications and for reducing losses of more reactive compounds such as benzo[a]pyrene. 相似文献
998.
利用DFT理论B3LYP/6-31+G(d, p)方法对六种PAHs分子进行理论计算, 可以得到六种多环芳烃分子的分子构型信息, 其中包括具体的键长、键角以及整个分子的长宽信息, 从而为我们能够更加深入地理解稠环芳烃的大小与环糊精内腔的尺寸匹配效应对SERS增强效果的影响提供了理论依据; 还利用Gaussview对这些分子的拉曼光谱给出具体的峰位, 并对计算出的六种多环芳烃的拉曼光谱进行主要峰位的指认。通过与实验测得拉曼光谱的对应关系, 从而对实验所得的拉曼光谱在理论上进行了有力的补充。 相似文献
999.
1000.
From S,N‐Heteroacene to Large Discotic Polycyclic Aromatic Hydrocarbons (PAHs): Liquid Crystal versus Plastic Crystalline Materials with Tunable Mechanochromic Fluorescence 下载免费PDF全文
Wei Yuan Prof. Xiang‐Kui Ren Mengwei Li Hongshuang Guo Yi Han Mengjiao Wu Qi Wang Dr. Miaomiao Li Prof. Yulan Chen 《Angewandte Chemie (International ed. in English)》2018,57(21):6161-6165
A novel type of discotic polycyclic aromatic hydrocarbon (PAH) based on an enlarged dibenzo[a,c]phenazine core has been developed. The large conjugated mesogenic core with increased dipole moment derived from S,N heteroatoms facilitates the formation of highly ordered columnar superstructures both in solution and bulk. Columnar mesophases, including liquid crystal (LC) and plastic crystal (PC) assemblies could form unprecedentedly based on the same PAH core. The cores are delicately modulated by the peripherical alkoxy chains. Both mesogens have mechanochromic fluorescent (MCF) character, which is also structure dependent and correlated with the different mesophase formation. For the first time, MCF properties can be realized in such a large conjugated mesogenic system. 相似文献