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251.
252.
Based on quantum chemistry calculations combined with the Marcus–Hush electron transfer theory, we investigated the charge‐transport properties of oligothiophenes (nTs) and oligopyrroles (nPs) (n=6, 7, 8) as potential p‐ or n‐type organic semiconductor materials. The results of our calculations indicate that 1) the nPs show intrinsic hole mobilities as high as or even higher than those of nTs, and 2) the vertical ionization potentials (VIPs) of the nPs are about 0.6–0.7 eV smaller than the corresponding VIPs of the nTs. Based on their charge‐transport ability and hole‐injection efficiency, the nPs have potential as p‐type organic semiconducting materials. Furthermore, it was also found that the maximum values of the electron‐transfer mobility for the nTs are larger by one‐to‐two orders of magnitude than the corresponding maximum values of hole‐transfer mobility, which suggests that the nTs have the potential to be developed as promising n‐type organic semiconducting materials owing to their electron mobility. 相似文献
253.
以乙二胺为结构导向剂,在200℃加热物质的量组成为nAl2O3:nP2O5:nen:nH2O=1:1:2:226的初始混合物(en=乙二胺),合成了三维开放骨架磷酸铝化合物AlPO4-12。用X-射线衍射、元素分析、pH测量、液体核磁共振以及电喷雾质谱研究了其晶化过程。依据质谱数据,开发了一个系统枚举在晶化过程中可能生成的小结构单元分子式的方法。研究发现在AlPO4-12的晶化过程中经历了层状磷酸铝UiO-15和UiO-13中间相,液相中Al物种的浓度极低,在晶化过程中生成的小结构单元中P-OH逐渐增多,乙二胺分子逐渐质子化,在晶化过程中生成了磷酸铝的4元环和6元环。用电喷雾质谱研究晶化过程中的液相可以获得小结构单元的结构和组成信息。 相似文献
254.
255.
A poly(4‐bromoaniline) (PBA) film is electrochemically synthesized on a gold electrode for the recognition of amino acids enantiomers. Scanning electron microscopy measurements show that the porous PBA films are made up of nano‐ribbons. At the PBA modified Au electrode differential pulse voltammograms of L ‐ and D ‐glutamic acids not only have very different current densities, but also produce different waveforms, providing an intuitive way to differentiate the two chiral molecules. Similar results are obtained in analyzing L ‐ and D ‐aspartic acids. Control experiments suggest that the observed sensing behavior arises from synergistic interactions between Au and the PBA film, where polymerization at the meta‐position creates a steric structure needed for differentiating chiral molecules. 相似文献
256.
257.
Hongbin Zhu Shu Liu Xue Li Fengrui Song Zhiqiang Liu Shuying Liu 《Analytical and bioanalytical chemistry》2013,405(23):7437-7445
A novel fingerprinting method, bioactivity fingerprint analysis, based on an ultrafiltration–ultraperformance liquid chromatography–multistage tandem mass spectrometry (UPLC–MS n ) method is proposed for the quality control of herbal medicines from the bioactivity viewpoint concerning the efficacy of herbal medicines. The bioactivity fingerprints reflecting the anti-inflammatory activities of radix Aconiti and radix Aconiti preparata were established. With use of ultrafiltration UPLC–MS n , 11 cyclooxygenase-2 ligands from radix Aconiti preparata and 14 cyclooxygenase-2 ligands from radix Aconiti were found after incubation with cyclooxygenase-2. Twelve of the cyclooxygenase-2 ligands were identified by the ultraperformance UPLC–MS n method. The enrichment factor of each peak in the bioactivity fingerprint was calculated and was demonstrated to be characteristic, which makes bioactivity fingerprint analysis for the quality control of herbal medicines possible from the viewpoint of their bioactivities. Figure
Bioactivity fingerprint analysis is defined as the chromatograms and spectra of the complex system of effective constituents containing information on their pharmacodynamic activities 相似文献
258.
Xi‐Kai Shu Jia Li Feng Liu Xiao‐Jing Lin Xiao Wang Chun‐Xia Song 《Journal of separation science》2013,36(16):2680-2685
This study aimed to seek an efficient method to extract and purify yunaconitine and 8‐deacetylyunaconitine from Aconitum vilmorinianum Kom. by accelerated solvent extraction combined with pH‐zone‐refining counter‐current chromatography. The major extraction parameters for accelerated solvent extraction were optimized by an orthogonal test design L9 (3)4. Then a separation and purification method was established using pH‐zone‐refining counter‐current chromatography with a two‐phase solvent system composed of petroleum ether/ethyl acetate/methanol/water (5:5:2:8, v/v) with 10 mM triethylamine in the upper phase and 10 mM HCl in the lower phase. From 2 g crude extract, 224 mg of 8‐deacetylyunaconitine (I) and 841 mg of yunaconitine (II) were obtained with a purity of over 98.0%. The chemical structures were identified by ESI‐MS and 1H and 13C NMR spectroscopy. 相似文献
259.
The introduction of sulfur atoms onto target molecules is an important area in organic synthesis, in particular in the synthesis of pharmaceutical compounds, and a wide variety of sulfuration agents have been developed for thionation reactions over the past few decades. In this Focus Review, we collect and summarize the C? S bond‐formation reactions that have been used to construct C? S bonds in natural products and pharmaceutical compounds. 相似文献
260.
Mengbo Zhou Li Song Feng Niu Kangying Shu Wenxiang Chai 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(5):463-466
In the title CuII complex, [Cu(C19H14O3P)2(C3H7NO)(H2O)2], the molecule is bisected by a twofold axis relating the two 2‐(diphenylphosphoryl)benzoate (ODPPB) ligands. The asymmetric unit consists of a CuII metal centre on the symmetry axis, an ODPPB ligand, one water ligand and one dimethylformamide (DMF) ligand (disordered around the twofold axis). The CuII ion has fivefold coordination provided by two carboxylate O atoms from two ODPPB ligands, two O atoms from two coordinated water molecules and another O atom from a (disordered) DMF molecule, giving a CuO5 square‐pyramidal coordination geometry. The ODPPB ligand adopts a terminal monocoordinated mode with two free O atoms forming two strong intramolecular hydrogen bonds with the coordinated water molecules, which may play a key role in the stability of the molecular structure, as shown by the higher release temperature for the coordinated water molecules than for the coordinated DMF molecule. The optical absorption properties of powder samples of the title compound have also been studied. 相似文献