共查询到20条相似文献,搜索用时 44 毫秒
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Stefan TsakovskiKarima Benkhedda Elisaveta IvanovaFreddy C Adams 《Analytica chimica acta》2002,453(1):143-154
8-Hydroxyquinoline (HQ), 2-methyl-8-hydroxyquinoline (CH3-HQ), 5,7-dichloro-2-methyl-8-hydroxyquinoline (Cl2-CH3-HQ), 5,7-dibromo-8-hydroxyquinoline (Br2-HQ), 5-sulfo-7-iodo-8-hydroxyquinoline (ferron) and 5-sulfo-8-hydroxyquinoline (SO3H-HQ) were compared as chelating reagents for on-line sorption preconcentration of cobalt in a knotted reactor (KR) precoated with the reagent. The results obtained with the different HQ derivatives reveal those properties of the chelating reagent responsible for the processes taking place in the KR. The influence of hydrophobicity, acidity, stability of the cobalt chelate and type of substituents in the HQ ring system on the separate steps of the flow injection (FI) preconcentration procedure are discussed. According to the performance characteristics of the different HQ derivatives, the most important parameters for on-line preconcentration in a KR are the hydrophobicity of the reagent and the stability of the chelate complex with the analyte. 相似文献
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LI Zhi-Feng ZHU Yuan-Cheng YUAN Kun KANG Jing-Wan 《结构化学》2008,27(1):63-69
The structures of 2,7'-(ethylene)-bis-8-hydroxyquinoline and its derivatives were optimized at the ground states using ab initio HF and B3LYP methods. At the same time, the molecular structures of the first singlet excited state for 2,7'-(ethylene)-bis-8-hydroxyqulnoline and its derivatives were optimized by CIS/6-31G(d). The absorption and emission spectra based on the above structures were obtained by the time-dependent density functional theory (TD-DFT) by the B3LYP method with the 6-31G(d) basis set. The calculated results of luminescence originate from the electronic transition from the hydroxphenol ring of 8-hydroxyquinoline A to the pyridine ring of 8-hydroxyquinoline B. Their luminescence wave bands can be tuned by different substituents on the ligand of 8-hydroxyquinoline. 相似文献
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《Analytical letters》2012,45(14):2487-2498
Abstract A colorimetric method for the determination of certain 8-hydroxyquinolines has been developed. The method is based on the coupling of 8-quinolinols with diazotriazole carboxylic acid in the presence of sodium carbonate (0.5% w/v) at ambient temperature (around 30°C). The resulting azo dyes are stable and give intense absorption in the range of 486–540 nm. Beer's law is valid in the concentration ranges of 1 – 8, 2.5 – 17.5, 5 – 35, 2 – 20, and 2 – 20 mcg/ml for 8-hydroxyquinoline (HQ), 5,7-diiodo-8-hydroxyquinoline (DIQ), 5,7-dibromo-8-hydroxyquinoline (DBQ), 5-chloro-7-iodo-8-hydroxyquinoline (CIQ) and 8-hydroxy-7-iodo-5-quinoline sulfonic acid (SIQ), respectively. The proposed method has been successfully applied for the determination of the studied compounds in pure form and in commercial formulations. The obtained results are in good agreement with those obtained from reported methods. 相似文献
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The orange compound formed between thorium(IV) and 8-hydroxyquinoline by conventional precipitation is non-stoichiometric. The composition is very sensitive to experimental conditions; the average ratio of bound 8-hydroxyquinoline to thorium was found to be 4.9:1. The deficiency of 8-hydroxyquinoline is due either to partial hydrolysis of thorium, or to the presence of co-ordinated water. A simple procedure for the preparation of the pure tetrakis compound is described. 相似文献
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在8-羟基喹啉存在下,分别采用水相法和两相法简便合成了5种取代水杨酸二茂钛配合物,并用元素分析、IR及 1H NMR等手段对配合物进行了结构表征,发现配合物中均不含8-羟基喹啉配体,而是形成以取代水杨酸为双齿配体的六元杂环化合物.用电子吸收光谱分别对两相反应体系(H2O/CHCl3)的水相和有机相进行了动态监测,发现8-羟基喹啉首先通过两相界面与有机相中的二氯二茂钛形成水溶性的过渡性配合物,然后该过渡性配合物再与有机相中的取代水杨酸作用形成了目标配合物. 相似文献
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Deraeve C Boldron C Maraval A Mazarguil H Gornitzka H Vendier L Pitié M Meunier B 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(2):682-696
Fourteen different ligands have been synthesized with two covalently linked 8-hydroxyquinoline motifs that favor metal complexation. These bis-chelators include different bridges at the C2 positions and different substituents to modulate their physicochemical properties. They can form metal complexes in a ratio of one ligand per metal ion with Cu II and Zn II, two metal ions involved in the formation of amyloid aggregates of the toxic Abeta-peptides in the Alzheimer disease. The apparent affinity of all bis-8-hydroxyquinoline ligands for Cu II and Zn II are similar with logK Cu II approximately 16 and logK Zn II approximately 13 and are 10,000 times more efficient than for the corresponding 8-hydroxyquinoline monomers. Their strong chelating capacities allow them to inhibit more efficiently than the corresponding monomers the precipitation of Abeta-peptides induced by Cu II and Zn II and also to inhibit the toxic formation of H2O2 due to copper complexes of Abeta. The best results were obtained with a one-atom linker between the two quinoline units. X-ray analyses of single-crystals of Cu II, Zn II or Ni II complexes of 2,2'-(2,2-propanediyl)-bis(8-hydroxyquinoline), including a one-atom linker, showed that all heteroatoms of the bis-8-hydroxyquinoline ligand chelate the same metal ion in a distorted square-planar geometry. The Cu II and Zn II complexes include a fifth axial ligand and are pentacoordinated. 相似文献
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Wagner CC González-Baró AC Baran EJ 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,79(5):1762-1765
The FTIR and FT-Raman spectra of the gallium(III) complexes of 8-hydroxyquinoline (oxine) and 5-chloro-7-iodo-8-hydroxyquinoline (clioquinol), were recorded and briefly discussed by comparison with the spectra of the uncoordinated ligands and with some related species. 相似文献
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The influence of sodium dodecyl sulfate on the dissociation of protonated 8-hydroxyquinoline in aqueous solutions is investigated by potentiometric titration at 293 K. The constants of direct binding of 8-hydroxyquinoline with the monomers and micelles of sodium dodecyl sulfate are determined by the computer simulation of the most probable processes. The role of electrostatic and hydrophobic interactions in the studied system is discussed.__________Translated from Kolloidnyi Zhurnal, Vol. 67, No. 2, 2005, pp. 231–234.Original Russian Text Copyright © 2005 by Ramenskaya, Vladimirova. 相似文献
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The extraction of tungsten by chloroform solutions of 8-hydroxyquinoline(I), 2-methyl-8-hydroxyquinoline(II), 5,7-dibromo-8-hydroxyquinoline(III) and 8-mercaptoquinoline(IV), as a function of the concentration of tungsten and reagent and the acidity of the aqueous phase, has been studied. Evidence was obtained for the quantitative extraction of tungsten over a wide range of acidity. The degree of extraction of tungsten at 10(-5)M concentration with I,III and IV gives two maxima when plotted against acidity. The extraction maximum for the more acidic solutions lies in the region where the reagents exist in the protonated form and its position depends on the reagent used. It is suggested that different tungsten complexes are extracted, depending on the acidity of the aqueous phase. 相似文献
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合成了 8-羟基喹啉与β-环糊精的包合物, 通过X射线单晶衍射研究了它的晶体结构. 结果显示其不对称单元包含2个β-环糊精、1个8-羟基喹啉, 2个乙醇和30个水分子. 其中两个β-环糊精分子通过仲羟基间氢键以头对头的方式形成二聚体, 客体8-羟基喹啉被包合在此二聚体的中间区域, 分子平面与环糊精的大环平面平行, 形成了一个具有三明治夹心结构的包合物. 两个环糊精空腔各包合一个乙醇分子, 30个水分子分散在β-环糊精二聚体之间. 研究表明, β-环糊精二聚体的三明治区域是疏水的, 对于某些大小合适且具有平面构型的客体分子, 如8-羟基喹啉, 此三明治区域比β-环糊精空腔具有更强的包合能力, 这种新颖的包合方式是乙醇与8-羟基喹啉竞争包合的结果. 相似文献
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The monomer, 5-methyl(2-methacryloylethyloxy)-8-quinolinol(HEMA-CH2-Hq), which possesses both double bond and 8-hydroxyquinoline groups, was synthesized from 2-hydroxyethyl methacrylate (HEMA) and 5-chloromethyl-8-quinolinol hydrochloride. The model polymer with 8-hydroxyquinoline ligands was obtained by free-radical copolymerization with styrene. So metaloquinolate (AlQ3, ZnQ2)-containing polymers are prepared by coordinating reaction with di(8-hydroxyquinoline) aluminum(AlQ2) chelates or mono(8-hydroxyquinoline) zinc(ZnQ) chelates without cross-linking. Both polymer and polymer complexes were analyzed by FT-IR, UV-vis, DSC, TGA and photoluminescence spectroscopies. They are soluble in common solvents and easy to form films. The use of AlQ2 and ZnQ avoided the cross-linking caused by the AlQ3, ZnQ2 formation between different polymer chains. High glass transition temperature, good thermal stability, and strong yellow-green fluorescence were observed for the prepared polymers. These polymers were expected to have the potential application in yellow-green OLEDs. 相似文献
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以8-羟基喹啉为原料,合成了5-(烯丙氧)甲基-8-羟基喹啉配体及其铝配合物,并通过红外光谱对配体和配合物进行了表征,通过荧光光谱研究了配合物的光致发光性能。 相似文献
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W. Żmijewska 《Journal of Radioanalytical and Nuclear Chemistry》1974,20(2):521-527
A substoichiometric extraction method of indium with 8-hydroxyquinoline and its application to the determination of indium in semiconductor silicon are described. 相似文献
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Amati M Belviso S Cristinziano PL Minichino C Lelj F Aiello I La Deda M Ghedini M 《The journal of physical chemistry. A》2007,111(51):13403-13414
The low fluorescence quantum yield of 8-hydroxyquinoline cannot be correctly interpreted without knowing the form that such a compound assumes in different environments. The commonly accepted emission-quenching excited-state proton transfer can follow different reaction paths if 8-hydroxyquinoline is dimeric or monomeric or if it exists in the form of cis and trans conformers; in this light, the knowledge of the compound form in a particular environment is basic. We have performed a spectroscopic and computational investigation aimed at the determination of the form of 8-hydroxyquinoline in different solvents. UV-vis, fluorescence, and IR spectral features have been assigned by ab initio computations based on the density functional theory and time-dependent density functional theory; the density functional theory and MP2 computations have been applied to the determination of the relative stability of the dimeric and monomeric cis and trans forms of 8-hydroxyquinoline in different solvents. Molecular dynamics computations have been used to determine the compound behavior in water solutions. According to our results, 8-hydroxyquinoline shows a clear preference for the cis conformation (as dimer or monomer), but, in water solutions, a small fraction of the trans conformation is also present. 相似文献
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This paper describes a photometric assay procedure for the determination of small amounts of 8-hydroxyquinoline, based on the formation of a blue indophenol derivative from the reaction of 8-hydroxyquinoline with N,2,6-trichloro-p-benzoquinoneimine. 相似文献
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The structures of 2,7′-(ethylene)-bis-8-hydroxyquinoline and its derivatives were optimized at the ground states using ab initio HF and B3LYP methods. At the same time, the molecular structures of the first singlet excited state for 2,7′-(ethylene)-bis-8-hydroxyquinoline and its derivatives were optimized by CIS/6-31G(d). The absorption and emission spectra based on the above structures were obtained by the time-dependent density functional theory (TD-DFT) by the B3LYP method with the 6-31G(d) basis set. The calculated results of luminescence originate from the electronic transition from the hydroxphenol ring of 8-hydroxyquinoline A to the pyridine ring of 8-hydroxyquinoline B. Their luminescence wave bands can be tuned by different substituents on the ligand of 8-hydroxyquinoline. 相似文献