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101.
102.
在自制的硅基纤维素-三(3,5-二甲基苯基氨基甲酸酯)高效液相色谱手性固定相上(HPLC-CSP),优化了1-(6'-甲氧基萘)乙醇氢酯基化反应产物-萘普生甲酯手性分离的条件,测定了相应的一系列不对称氢酯基化反应产物的对映体过剩值(e.e.值)。结果表明,在CDMPC-CSP手性柱上用HPLC测定此类不对称催化反应的光学产率,评价催化剂体系的手性选择是一种非常理想的方法。 相似文献
103.
氨基酸柱前衍生化的3种新荧光试剂的光谱特性及高效液相色谱研究 总被引:1,自引:2,他引:1
合成了3种新的荧光标记试剂:吖啶-N-乙酰氯,咔唑-9-乙酰氯和咔唑-9-丙酰氯。它们的最大发射降激发波长分别为430nm,368nm,和365nm。3种衍生化试剂与氨基酸形成的衍生物在pH6.5的条件下结合梯度洗脱程序在C18反相柱上对色谱条件进行了优化。 相似文献
104.
Zhong‐Zhen Yu Ming Lei Yu‐Chun Ou Guisheng Yang Guo‐Hua Hu 《Journal of Polymer Science.Polymer Physics》2000,38(21):2801-2809
A reactive extrusion process was developed to toughen an amorphous copolyester (PETG) of ethylene glycol, terephthalic acid and 1,4‐cyclohexanedimethanol using either a maleic anhydride grafted polyethylene–octene elastomer (POEg), or a maleic anhydride grafted mixture (TPEg) of the polyethylene–octene elastomer and a semicrystalline polyolefin plastic as the impact modifier. TPEg showed an important toughening effect on the PETG. A sharp ductile‐brittle transition was observed when the TPEg content was about 10 wt %. For POEg toughened PETG, the ductile–brittle transition required a higher content in POEg, ∼15 wt %. Evolution of the topography and morphology of the blends and the relationship between impact strength and topography were discussed. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 2801–2809, 2000 相似文献
105.
在磷酸催化作用下,采用前体二胺N,N’-(2-胺基苯基)-2,6-二甲酰亚胺吡啶(1)和前体二醛1,4-二(2’-甲酰苯氧基)丁烷(2)进行缩合作用得到[1+1]Schiff碱大环化合物3,进一步将Schiff碱大环3还原得到饱和大环4.并采用1H NMR,IR,质谱和元素分析等技术对大环3和4的组成进行了表征.采用X射线单晶衍射技术测定了Schiff碱大环3的晶体结构,结果表明大环3具有扭曲的"8"字形结构.采用UV-vis光谱滴定技术对大环与系列阴离子的键合作用进行了考察,结果表明,Schiff碱大环3对F-离子有明显的选择性识别作用,并测定了该配位反应的配位比和平衡常数. 相似文献
106.
Pingchun Wei Kai Zhang Dr. Xin Li Deying Meng Prof. Dr. Hans Ågren Prof. Dr. Zhongping Ou Prof. Dr. Seikweng Ng Prof. Dr. Hiroyuki Furuta Prof. Dr. Yongshu Xie 《Angewandte Chemie (International ed. in English)》2014,53(51):14069-14073
The first neo‐confused hexaphyrin(1.1.1.1.1.0) was synthesized by oxidative ring closure of a hexapyrrane bearing two terminal “confused” pyrroles. The new compound displays a folded conformation with a short interpyrrolic C???N distance of 3.102 Å, and thus it readily underwent ring fusion to afford a neo‐fused hexaphyrin with an unprecedented 5,5,5,7‐tetracyclic ring structure. Furthermore, coordination of CuII triggered a ring opening/contracting reaction to afford a CuII complex of an N‐linked pentaphyrin derivative. The roles of reactive N? C bonds in the porphyrinoid macrocycles were demonstrated. 相似文献
107.
Bridge‐Localized HOMO‐Binding Character of Divinylanthracene‐Bridged Dinuclear Ruthenium Carbonyl Complexes: Spectroscopic,Spectroelectrochemical, and Computational Studies 下载免费PDF全文
Ya‐Ping Ou Jing Zhang Meng Xu Jianlong Xia Prof. František Hartl Prof. Dr. Jun Yin Prof. Dr. Guang‐Ao Yu Prof. Dr. Sheng Hua Liu 《化学:亚洲杂志》2014,9(4):1152-1160
The electronic properties of four divinylanthracene‐bridged diruthenium carbonyl complexes [{RuCl(CO)(PMe3)3}2(μ? CH?CHArCH?CH)] (Ar=9,10‐anthracene ( 1 ), 1,5‐anthracene ( 2 ), 2,6‐anthracene ( 3 ), 1,8‐anthracene ( 4 )) obtained by molecular spectroscopic methods (IR, UV/Vis/near‐IR, and EPR spectroscopy) and DFT calculations are reported. IR spectroelectrochemical studies have revealed that these complexes are first oxidized at the noninnocent bridging ligand, which is in line with the very small ν(C?O) wavenumber shift that accompanies this process and also supported by DFT calculations. Because of poor conjugation in complex 1 , except oxidized 1+ , the electronic absorption spectra of complexes 2+ , 3+ , and 4+ all display the characteristic near‐IR band envelopes that have been deconvoluted into three Gaussian sub‐bands. Two of the sub‐bands belong mainly to metal‐to‐ligand charge‐transfer (MLCT) transitions according to results from time‐dependent DFT calculations. EPR spectroscopy of chemically generated 1+ – 4+ proves largely ligand‐centered spin density, again in accordance with IR spectra and DFT calculations results. 相似文献
108.
Amily Fang-ju Jou Chun-Hua Lu Yen-Chuan Ou Shian-Shiang Wang Shih-Lan Hsu Itamar Willner Ja-an Annie Ho 《Chemical science》2015,6(1):659-665
The microRNA, miR-141, is a promising biomarker for prostate cancer. We implement here a two-step sensing platform for the sensitive detection of miR-141. The first step involves the use of semiconductor CdSe/ZnS quantum dots (QDs) modified by FRET quencher-functionalized nucleic acids, that include the recognition sequence for miR-141 and a telomerase primer sequence for the second step of the analytical platform. Subjecting the probe-modified QDs to miR-141, in the presence of duplex specific nuclease, DSN, leads to the formation of a miR-141/probe duplex and to its DSN-mediated cleavage, while regenerating the miR-141. The DSN-induced cleavage of the quencher units leads to the activation of the fluorescence of the QDs, thus allowing the optical detection of miR-141 with a sensitivity corresponding to 1.0 × 10–12 M. The nucleic acid residues associated with the QDs after cleavage of the probe nucleic acids by DSN act as primers for telomerase. The subsequent telomerase/dNTPs-stimulated elongation of the primer units forms G-quadruplex telomer chains. Incorporation of hemin in the resulting G-quadruplex telomer chains yields horseradish peroxidase-mimicking DNAzyme units, that catalyze the generation of chemiluminescence in the presence of luminol/H2O2. The resulting chemiluminescence intensities provide a readout signal for miR-141, DL = 2.8 × 10–13 M. The first step of the sensing platform is non-selective toward miR-141 and the resulting fluorescence may be considered only as an indicator for the existence of miR-141. The second step in the sensing protocol, involving telomerase, provides a selective chemiluminescence signal for the existence of miR-141. The two-step sensing platform is implemented for the analysis of miR-141 in serum samples from healthy individuals and prostate cancer carriers. Impressive discrimination between healthy individuals and prostate cancer carriers is demonstrated. 相似文献
109.
β-羰基膦酸酯是一类重要的有机化合物和反应中间体,在有机合成及药物化学中发挥着重要的作用.提供了一种高原子经济性、高选择性、温和的炔基膦酸酯水合反应体系.实验结果表明:在阳离子金催化剂(2.5 mol%)的催化作用下,以1,2-二氯乙烷(1 m L)为溶剂,室温下炔基膦酸酯(1 mmol)与水(3 mmol)发生水合反应,高收率、高区域选择性地得到β-羰基膦酸酯化合物(收率≥92%).该方法具有底物适用范围广、反应条件温和、环境友好等优点,为含β-羰基膦酸酯结构单元的天然产物及复杂药物分子的合成提供了一种新途径. 相似文献
110.
Wei Shi Jian‐Jun Liu Xiang‐Ping Ou Chang‐Cang Huang 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(4):289-293
A homochiral helical three‐dimensional coordination polymer, poly[[(μ2‐acetato‐κ3O,O′:O)(hydroxido‐κO)(μ4‐5‐nicotinamido‐1H‐1,2,3,4‐tetrazol‐1‐ido‐κ5N1,O:N2:N4:N5)(μ3‐5‐nicotinamido‐1H‐1,2,3,4‐tetrazol‐1‐ido‐κ4N1,O:N2:N4:N5)dicadmium(II)] 0.75‐hydrate], {[Cd2(C7H5N6O)2(CH3COO)(OH)]·0.75H2O}n, was synthesized by the reaction of cadmium acetate, N‐(1H‐tetrazol‐5‐yl)isonicotinamide (H‐NTIA), ethanol and H2O under hydrothermal conditions. The asymmetric unit contains two crystallographically independent CdII cations, two deprotonated 5‐nicotinamido‐1H‐1,2,3,4‐tetrazol‐1‐ide (NTIA−) ligands, one acetate anion, one hydroxide anion and three independent partially occupied water sites. The two CdII cations, with six‐coordinated octahedral and seven‐coordinated pentagonal bipyramidal geometries are located on general sites. The tetrazole group of one symmetry‐independent NTIA− ligand links one of the independent CdII cations into 61 helical chains, while the other NTIA− ligand links the other independent CdII cations into similar but unequal 61 helical chains. These chains, with a pitch of 24.937 (5) Å, intertwine into a double‐stranded helix. Each of the double‐stranded 61 helices is further connected to six adjacent helical chains through an acetate μ2‐O atom and the tetrazole group of the NTIA− ligand into a three‐dimensional framework. The helical channel is occupied by the isonicotinamide groups of NTIA− ligands and two helices are connected to each other through the pyridine N and carbonyl O atoms of isonicotinamide groups. In addition, N—H...O and O—H...N hydrogen bonds exist in the complex. 相似文献