共查询到20条相似文献,搜索用时 15 毫秒
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Molecular Diversity - A facile, inexpensive and eco-friendly synthesis of functionalised... 相似文献
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在 p H10 .5的 Na2 B4O7- Na OH介质及 CS(NH2 ) 2 、氯化十六烷基吡啶 (CPC)存在时 ,室温下镍 ( )与5 - (4 -氯苯基偶氮 ) - 8-苯磺酰氨基喹啉 (CPBSQ)反应 ,生成络合比为 1∶ 4的有色络合物 ,其最大吸收波长位于 6 0 0 nm。研究了反应的最佳条件 ,建立了一个测定 Ni( )的光度分析新方法。 Ni( )的浓度在 0—10 .0 μg/2 5 m L范围内符合比耳定律 ,其摩尔吸光系数为 1.93× 10 5L· mol-1·cm-1。考察了 2 0多种共存离子的影响 ,大多数常见离子在氨水沉淀分离后不干扰测定。方法用于合金钢中镍的测定 ,其相对标准偏差为 1.9%— 2 .1% ,标准加入回收率为 97%— 10 4 %。 相似文献
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Low energy electron diffraction (LEED) patterns for the GeSi(111)-5 × 5 surface are reported and compared to those for the Si(111)-7 × 7 surface. Parallels between the observed LEED patterns are explained by a structural analogy between GeSi(111)-5 × 5 and Si(111)-7 × 7 surfaces. Both the (5 × 5) and (7 × 7) patterns are shown to be consistent with structural models of the triangle-dimer type previously proposed for Si(111)-7 × 7 surface. 相似文献
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M. Jozefowicz J. R. Heldt J. Heldt 《The European physical journal. Special topics》2013,222(9):2373-2379
The absorption and fluorescence transition dipole moments ( $\hat M_{ge}$ and $\hat M_{eg}$ ) for ethyl 5-(4-aminophenyl)-3-amino-2, 4-dicyanobenzoate (EAADCy) and ethyl 5-(4-dimethylaminophenyl)-3-amino-2, 4-dicyanobenzoate (EDMAADCy) have been determined on the basis of the steady-state and time-resolved spectroscopic measurements and semiempirical quantum-chemical calculations. The values of the transition dipole moments of perpendicular and flattened forms of the investigated molecules were estimated as a function of the solvent polarity. Noted differences between the absorption and emission transition dipole moments (i.e., ${{\hat M_{ge} } \mathord{\left/ {\vphantom {{\hat M_{ge} } {\hat M_{eg} }}} \right. \kern-0em} {\hat M_{eg} }} \ne 1$ ) confirm that the change of the electronic and molecular structure take place in the excited state. 相似文献
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以丹磺酰胺为荧光基团设计合成了新型Zn2+荧光探针DW1(5-(二甲基氨基)-N-(4-(2-(2-喹啉亚甲基)甲酰肼基)苯基)萘-1-磺酰胺)。通过紫外光谱、荧光光谱及电喷雾质谱研究了DW1对Zn2+的选择性识别作用。结果表明,DW1与Zn2+结合后荧光显著增强,荧光发射光谱由545 nm蓝移至515 nm,量子产率达到0.32,且对Zn2+具有较高的选择性,受常见离子的干扰较小。光谱滴定和ESI-MS谱表明DW1与Zn2+以1∶1的化学计量数形成配合物,平衡常数K=1.75×104(mol/L)-1。 相似文献
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Mariusz Gago? Arkadiusz Matwijczuk Daniel Kami��ski Andrzej Niewiadomy Rados?aw Kowalski Grzegorz P. Karwasz 《Journal of fluorescence》2011,21(1):1-10
Spectroscopic studies of the biologically active compound 2-(4-fluorophenylamino)-5-(2,4-dihydroxybenzeno)-1,3,4-thiadiazole (FABT), have been performed. Absorption studies in the UV-Vis region for FABT in polar solvents, like water or ethanol, exhibit the domination of the enol form over its keto counterpart, with a broad absorption band centered around 340 nm. In non-polar solvents such as n-heptane or heavier alkanes the 340 nm absorption band disappears and an increase of the band related to the keto form (approximately 270 nm) is observed. Fluorescence spectra (with 270 nm and 340 nm excitation energies used) show a similar dependence: for FABT in 2-propanol a peak at about 400 nm dominates over that at 330 nm while in n-heptane this relation is reversed. The solvent dependent equilibrium between the keto and enol forms is further confirmed by FTIR and Raman spectroscopies. As can be expected, this equilibrium also shows some temperature dependences. We note that the changes between the two tautomeric forms of FABT are not related to the permanent dipole moment of the solvent but rather to its dipole polarizability. 相似文献
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Synthesis of( E ) -5- ( dimethylamino ) -N- ( 4- ( 2- ( quinolin-2-ylmethylene ) -hydrazinecarbonyi ) phenyl ) naphthalene-1-sulfonamide for Detection of Zinc Ion 下载免费PDF全文
以丹磺酰胺为荧光基团设计合成了新型Zn2+荧光探针DW1(5-(二甲基氨基)-N-(4-(2-(2-喹啉亚甲基)甲酰肼基)苯基)萘-1-磺酰胺).通过紫外光谱、荧光光谱及电喷雾质谱研究了DW1对Zn2+的选择性识别作用.结果表明,DW1与Zn2+结合后荧光显著增强,荧光发射光谱由545nm蓝移至515nm,量子产率达到0.32,且对Zn2具有较高的选择性,受常见离子的干扰较小.光谱滴定和ESI-MS谱表明DW1与Zn2+以1:1的化学计量数形成配合物,平衡常数K=1.75×104(mol/L)-1. 相似文献
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Atomic and electronic structures of the SrTiO3(100)-(square root of 5 x square root of 5) - R26.6 degrees surface are studied by using scanning tunneling microscopy (STM) and noncontact atomic force microscopy (NC-AFM). Instead of the well established oxygen vacancy model, it is found that a structural model, consisting of an ordered Sr adatom at the oxygen fourfold site of a TiO2 terminated layer, can explain the experimental results very well. We theoretically simulate the model cluster with the first-principles total-energy calculation. Calculated density of states and images for STM and NC-AFM are in good agreement with the experimental results. 相似文献
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Mingliang Wang Junxiang ZhangJuzheng Liu Chunxiang XuHuangxian Ju 《Journal of luminescence》2002,99(1):79-83
The absorption and photoluminescence of the newly synthesized 5-(9-anthryl)-3-(4-nitrophenyl)-1-phenyl-2-pyrazoline (AN PP) were investigated. The absorption is the absorption of anthryl moiety at about 325-400 nm, superimposed on the broader absorption of 3-(4-nitrophenyl)-1-phenyl-2-pyrazoline moiety peaked at 420 nm. On excitation at 420 nm, the fluorescence spectrum has only one emission band from the pyrazoline moiety. This emission band exhibits a larger red shift with an increase in the polarity of solvents. But on excitation at 365 nm, the fluorescence spectrum has two emission bands coming from the anthryl and pyrazoline moieties, respectively. The intensity ratio of the two bands is different in solvents of different polarity. It is concluded that photo-induced intramolecular energy transfer from the anthryl to pyrazoline moiety exists simultaneously with the charge transfer from N (1) to C (3) in the pyrazoline moiety in the excited state and both compete with each other. 相似文献
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以(2R,5S)-2,5-二甲基哌嗪为原料,经过成盐,单取代反应,用D-酉石酸对光学异构体的手性拆分,用氢氧化钠游离,最终合成(2R,5S)-N-间氟苄基-2,5-二甲基哌嗪,反应总收率为83%.该物质的合成未见文献报道,目标化合物用1H NMR,IR进行结构表征. 相似文献
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5-(2-苯并噻唑偶氮)-8-氨基喹啉作为钴的光度分析试剂及应用研究 总被引:4,自引:1,他引:3
在阳离子表面活性剂溴化十六烷基三甲基铵存在下 ,于 p H=9.2的硼砂缓冲介质中 ,5 - (2 -苯并噻唑偶氮 ) - 8-氨基喹啉与钴 ( )形成 2∶ 1的蓝色配合物 ,其最大吸收波长位于 6 5 0 nm处 ,表观摩尔吸光系数为 1.2 4× 10 5L· mol-1· cm-1。钴浓度在 0— 10 .0μg/2 5 m L范围内 ,符合比耳定律。应用于维生素 B12 和水系沉积物中微量钴的测定 ,获得了满意的结果。 相似文献