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Sample records for 8-quinolinol

  1. Studies on the extraction of lanthanide complexes with 8-quinolinol

    The solvent extraction of Dy(3), Er(3), Yb(3) and Lu(3) by 8-quinolinol (HOx) in CHCl3 from aqueous and polar aqueous-methanol phase has been studied as a function of pH(pHx) or the concentration of HOx in the organic phase. The data suggest that the equation for the extraction reaction from the aqueous phase is Ln(H2O)y(aq)3+ + 3HOx(o)↔ LnOx3(o) + 3H(aq)+ + yH2O where: Ln = Dy, Er, Yb. The extraction equilibrium constants of reaction, two-phase stability constants for the DyOx3, ErOx3 and YbOx3 complexes, pH 0.5, pH0.5x and separation factor have been evaluated. Methanol causes a synergistic effect. 3 figs., 1 tab. 33 refs. (author)

  2. Separation of Metal Complexes with Counter Ions by Tube Radial Distribution Chromatography Using a Ternary Solvent Containing 8-quinolinol.

    Kawai, Yuji; Fujinaga, Satoshi; Hashimoto, Masahiko; Tsukagoshi, Kazuhiko

    2015-01-01

    An open-tubular capillary chromatography system (tube radial distribution chromatography, TRDC) was developed using a ternary solvent (water-acetonitrile-ethyl acetate; volume ratio, 3:8:4) containing 10 mmol L(-1) 8-quinolinol for the separation of nitrate, chloride, and sulfate compounds of Ni(II), Al(III), and Fe(III). When a mixed solution of the Ni(II) compounds was injected into an untreated fused-silica capillary tube (90 cm × 75 μm i.d.) with a ternary solvent flow rate of 0.8 μL min(-1), the compounds were eluted in the following order: [Ni(II)-(8-quinolinol)3] complex, [Ni(II)-(8-quinolinol)]-nitrate ion interaction complex, [Ni(II)-(8-quinolinol)]-chloride ion interaction complex, and [Ni(II)-(8-quinolinol)]-sulfate ion interaction complex. The elution of mixtures of the Al(III) and Fe(III) compounds showed similar trends. PMID:26561263

  3. Metabolism of chinoform(5-chloro-7-iodo-8-quinolinol)-14C in dog

    Chinoform (6-chloro-7-iodo-8-quinolinol)-14C (302.4μCi/83 mg) packed in a capsule was given orally to a dog weighing 10.5 kg, and the urine and feces were collected for 5 days after dosing. Excretion of a large portion of the radioactivity in urine and feces was observed on the 1st day and 3rd day after dosing. The total radioactivity in both excreta in 5 days was about 70% of dose. The urine was used for the study of metabolites. The urine was extracted with a mixture of benzene and pyridine (9:1), and an organic layer and an aqueous layer were obtained. Intact chinoform and 5-chloro-8-quinolinol (a deiodinated product of chinoform) were identified in the organic layer by radiochromatography and by an isotope dilution method. From the water layer of urine, glucuronides of chinoform and the deiodinated product, and sulfate of chinoform were identified as the metabolites. (author)

  4. Simple activation by acid of latent Ru-NHC-based metathesis initiators bearing 8-quinolinolate co-ligands

    Wappel, Julia

    2016-01-28

    A straightforward synthesis utilizing the ring-opening metathesis polymerization (ROMP) reaction is described for acid-triggered N,O-chelating ruthenium-based pre-catalysts bearing one or two 8-quinolinolate ligands. The innovative pre-catalysts were tested regarding their behavior in ROMP and especially for their use in the synthesis of poly(dicyclopentadiene) (pDCPD). Bearing either the common phosphine leaving ligand in the first and second Grubbs olefin metathesis catalysts, or the Ru–O bond cleavage for the next Hoveyda-type catalysts, this work is a step forward towards the control of polymer functionalization and living or switchable polymerizations.

  5. Simple activation by acid of latent Ru-NHC-based metathesis initiators bearing 8-quinolinolate co-ligands

    Wappel, Julia; Fischer, Roland C; Cavallo, Luigi; Slugovc, Christian

    2016-01-01

    Summary A straightforward synthesis utilizing the ring-opening metathesis polymerization (ROMP) reaction is described for acid-triggered N,O-chelating ruthenium-based pre-catalysts bearing one or two 8-quinolinolate ligands. The innovative pre-catalysts were tested regarding their behavior in ROMP and especially for their use in the synthesis of poly(dicyclopentadiene) (pDCPD). Bearing either the common phosphine leaving ligand in the first and second Grubbs olefin metathesis catalysts, or the Ru–O bond cleavage for the next Hoveyda-type catalysts, this work is a step forward towards the control of polymer functionalization and living or switchable polymerizations. PMID:26877818

  6. The kinetics and mechanism of the reaction of uranium(VI) with 8-quinolinol and 8-hydroxy-5-quinolinesulfonic acid

    The kinetics of the reaction of uranium(VI) with 8-quinolinol and 8-hydroxy-5-quinolinesulfonate under the conditions of 1:1 chelate formation in the pH range 3.6-4.6 at different temperatures (20-30degC) and ionic strength I = 0.1 moldm-3 (KNO3) have been studied. A dual path mechanism involving both UO2(aq)2+ and UO2(OH)(aq)+ and the partially deprotonated ligand (LH, LH-) is consistent under the experimental conditions. The different rate constants under the condition of equilibrium have been determined. The results conform to kobs/B = k1[H+] + k2Kh; where B = (1/Q) + Ka(1)TU / ([H+] + Ka(1)) (Kh + [H+]); Kh = hydrolysis constant of UO2(aq)2+; Ka(1) = first deprotonation constant of the ligand, LH2 (charges are omitted); k1 and k2 are the second order forward rate constants of UO2(aq)2+ and UO2(OH)(aq)+ respectively and Q is the equilibrium constant of the reaction, UO22+ + LH ↔ UO2L+ + H+, where LH represents the partially deprotonated form of the ligand, 8-quinolinol and a similar reaction occurs for deprotonated 8-hydroxy-5-quinolinesulfonate (LH-). Thermodynamic parameters for each of the steps have been determined. The results have been compared with those of recent findings in the interaction of cerium(VI) and iron(III) with these ligands. UO2(aq)2+ has been argued to react through a dissociative interchange (Id) mechanism and its characteristic water exchange rate has been found as a rough estimate. Similarly for UO2(OH)(aq)+, a dissociative mechanism has been speculated. (author)

  7. Pressure dependence of supercritical carbon dioxide extraction equilibrium of palladium(II)with 2-methyl-8-quinolinol

    Pressure effect on the distribution of Pd(II) between an aqueous chloride solution and a supercritical carbon dioxide phase in the presence of 2-methyl-8-quinolinol (HMQ) as a chelating extractant has been investigated. The distribution ratio (D) of Pd(II) extracted as Pd(MQ)2 complex does not depend on the pressure in the range of 8.5 to 23 MPa, when the pH of the aqueous solution is buffered at pH 2.77∼2.96. The CO2 pressure affects the solubility of CO2 in the aqueous phase and therefore the pH of the non-buffered aqueous solution changed with the pressure, which leads to a change of D with the pressure. The extraction of Pd(II) into the supercritical CO2 using HMQ is promising for the recovery of Pd(II) in the aqueous chloride media. The HMQ forms the water-soluble protonated species, H2MQ|, which allows the coexistence of HMQ of enough high concentration in the extraction system. (author)

  8. Multielement preconcentration of trace heavy metals in seawater with an emulsion containing 8-quinolinol for graphite-furnace atomic absorption spectrometry

    A water-in-oil type emulsion containing 8-quinolinol has been used for the concentration of traces of heavy metals from seawater prior to their determinations by graphite-furnace atomic absorption spectrometry. The emulsion used was prepared by dissolving 40 mg of 8-quinolinol and 60 mg of sorbitan monooleate (Span-80) in 3.0 ml of toluene and vigorously mixing with 0.70 ml of aqueous hydrochloric acid solution (1.5 mol l-1) by ultrasonic irradiation. The resulting emulsion was gradually injected into 100 ml of sample solution (pH 8.5) and dispersed by stirring as numerous tiny globules. Four heavy metals (Co, Ni, Cu, and Cd) in the sample solution were quantitatively transported through the organic layer into the acidic aqueous droplets encapsulated in the emulsion. After collecting the dispersed emulsion globules, they were demulsified by heating and the heavy metals in the segregated aqueous phase were determined by atomic absorption spectrometry. Owing to the highly efficient concentration (100-fold), these heavy metals at sub-ng ml-1 levels in seawater were determined with satisfactory accuracy and precision, being confirmed with certified reference samples

  9. Ionic Self-Assembly and Red-Phosphorescence Properties of a Charged Platinum(II) 8-Quinolinol Complex Associated with Ammonium-Based Amphiphiles.

    Camerel, Franck; Vacher, Antoine; Jeannin, Olivier; Barberá, Joaquín; Fourmigué, Marc

    2015-12-21

    A series of ionic associates based on the platinum(II) chelate of 5-sulfo-8-quinolinol, [Pt(qS)2](2-), and ammonium-based amphiphiles is described. At variance with the prototypical neutral complex Pt(q)2 (q=8-quinolinol), these dianionic fluorophores, functionalized at the periphery with sulfonate groups, can be associated by the ionic self-assembly approach with various ammonium cations, such as (H2n+1Cn)2Me2N(+) (n=12, 16, 18) or complex ammonium cations carrying three Cn carbon chains (n=12, 14, 16) and an additional amide group. Investigations of their luminescence properties in solution, in the solid state, and, when possible, in thin films revealed that the phosphorescence properties in condensed phases are directly correlated to intermolecular interactions between the luminescent [Pt(qS)2](2-) centers. Of particular interest is also the formation of a columnar liquid-crystalline phase around room temperature (between -25 and +180 °C), as well as the very good film-forming ability of some of these fluorophores from organic solvents. PMID:26552608

  10. Solvent extraction of lanthanum (III), europium (III), and lutetium (III) with 5,7-dichloro-8-quinolinol into chloroform in the absence and presence of tetrabutylammonium ions or trioctylphosphine oxide

    The solvent extractions of lanthanum(III), europium(III), and lutetium(III) (M3+) in 0.1 moldm-3 sodium nitrate solutions with 5,7-dichloro-8-quinolinol (HA) into chloroform were studied in both the absence and presence of tetrabutylammonium ions (tba+) or trioctylphosphine oxide (TOPO). In the absence of tba+ or TOPO, the extracted species were the MA3 and MAHA (self-adduct), though MA4-tba+ was found when tba+ was added; MA3TOPO and MA3(TOPO)2 were found when TOPO was added in addition to the above mentioned two species. The anionic complex or TOPO adducts greatly enhanced the extraction. The data were statistically analyzed and the equilibrium constants for the extraction of these species, as well as the constants for the association of the HA, the A-tba+, or the TOPO on the MA3 in the organic phase, were determined. The extraction of the MA3 is better in the order LaA333. Although the values of the association constant of the HA or the TOPO on the MA3 are rather similar for the three metal chelates, the constants for A-tba+ are larger in the same order as mentioned above. Thus, the separation of these three metal ions by solvent extraction with this chelating extractant is not much affected by the addition of TOPO, but is greatly improved by the addition of tba+. (author)

  11. Separation of U(VI) from aqueous solutions by precipitate flotation with 8-quinolinol and surfactants

    Foam separation investigations over the 2.5-10.5 pH range show that U(VI) can be successfully separated from aqueous solutions by precipitation with oxine and subsequent flotation of the precipitate, either in absence or in presence of surfactant collectors. Collectors tested were: cetyl trimethyl ammonium bromide (CTAB) and sodium lauryl sulphate (NaLS). The extent of removal depends on many factors and removals as high as 98% could be achieved when uranyl oxinate precipitate was floated, under certain controlled conditions, in the presence of CTAB. Factors affecting the percentage removal were investigated and the best conditions were selected. The results obtained are discussed in terms of the hydrolytic behaviour of U(VI)

  12. Cancer stem/progenitor cell active compound 8-quinolinol in combination with paclitaxel achieves an improved cure of breast cancer in the mouse model

    Zhou, Jiangbing; Zhang, Hao; Gu, Peihua; Margolick, Joseph B.; Yin, Deling; Zhang, Ying

    2008-01-01

    Increasing evidence suggests that breast cancer is caused by cancer stem cells and the cure of breast cancer requires eradication of breast cancer stem cells. In this study, we established and characterized a sphere culture model derived from side population cells from the human breast cancer cell line MCF7. The sphere culture could be maintained long term and was enriched in cells expressing known breast cancer stem cell marker CD44+CD24−. These sphere cells showed higher colony formation ab...

  13. Synthesis, Characterization and Catalytic Performance of Copper( Ⅱ )-8-quinolinol Functionalized SBA-15%8-羟基喹啉铜(Ⅱ)功能化SBA-15的制备、表征及催化性质

    王虹苏; 黄家辉; 徐臣; 徐玲; 宋科; 徐海燕; 王竹倩; 阚秋斌

    2007-01-01

    利用3-氨丙基功能化的介孔SBA-15(APS-SBA-15)作为载体, 通过C-N共价键将8-羟基喹啉铜(Ⅱ)固定到APS-SBA-15孔道中, 制备了8-羟基喹啉铜(Ⅱ)功能化的SBA-15催化剂[Cu(Ⅱ)-Q-APS-SBA-15], 并将其用于以质量分数30%的过氧化氢为氧化剂的苯酚羟化反应中. 结果表明, Cu(Ⅱ)-Q-APS-SBA-15呈现出较高的苯酚转化率和苯二酚选择性.

  14. ORGANIC CHELATING REAGENT ON REDOX ADSORPTION OF ACTIVATED CARBON FIBER TOWARDS Au3+

    2002-01-01

    Organic chelating reagent influences upon the redox adsorption of activated carbon fibertowards Au3- were systematically investigated. The experimental results indicated that the presenceof organic chelating reagent on activated carbon fiber strongly affects adsorption capacity ofactivated carbon fiber towards Au3+. The reduction-adsorption amount of Au3+ increased three timesby the presence of 8-quinolinol. Furthermore, The reduction-adsorption amount of Au3+ depended onthe pH value of adsorption and temperature.

  15. Composition and stability of Nb(V), Zr(IV), Y(III) and La(III) chelates with 7-nitroso-8-quinolinone-5-sulphonate

    New Nb(V), Zr(IV), Y(III) and La(III) chelates obtained from disodium salt of 7-nitroso-8-quinolinole-5-sulphonic acid were studied using spectrophotometric, conductimetric and potentiometric methods. The solid chelates were synthesized and their ir spectra and elemental analysis were discussed. The ligand is bonded to the metal ion through the oxygens of nitroso and hydroxy groups. The apparent stability constants of the complexes formed in solution were also determined spectrophotometrically and potentiometrically

  16. Structural dynamics of nitrosylruthenium isomeric complexes studied with steady-state and transient pump-probe infrared spectroscopies.

    Zhao, Yan; Yang, Fan; Wang, Jianru; Yu, Pengyun; Pan, Huifen; Wang, Hongfei; Wang, Jianping

    2016-09-01

    The characteristic nitrosyl stretching (NO) in the region of 1800-1900cm(-1) was used to study the geometric and ligand effect on two nitrosylruthenium complexes, namely [Ru(OAc)(2QN)2NO] (QN=2-chloro-8-quinolinol (H2cqn) or QN=2-methyl-8-quinolinol (H2mqn)). The NO stretching frequency (νNO) was found in the following order: νcis-1 (2cqn)>νcis-2 (2cqn)>νcis-1 (2mqn)>νtrans (2mqn). The results exhibited a spectral sensitivity of the NO mode to both charge distribution and ligand arrangement, which was supported by ab initio computations and natural bond orbital (NBO) analyses. Further, the vibrational population of the vibrationally excited NO stretching mode was found to relax on the order of 7-10ps, showing less than 30% variation from one isomer to another, which were explained on the basis of NO local structures and solute-solvent interactions in these isomeric nitrosylruthenium complexes. PMID:27209490

  17. Covalent heterogenization of discrete bis(8-quinolinolato)dioxomolybdenum(VI) and dioxotungsten(VI) complexes by a metal-template/metal-exchange method: Cyclooctene epoxidation catalysts with enhanced performances

    Yang, Ying; Chattopadhyay, Soma; Shibata, Tomohiro; Ren, Yang; Lee, Sungsik; Kan, Qiubin

    2014-05-01

    A metal-template/metal-exchange method was used to imprint covalently attached bis(8- quinolinolato)dioxomolybdenum(VI) and dioxotungsten(VI) complexes onto large surface-area, mesoporous SBA-15 silica to obtain discrete MoO2 VIT and WO2 VIT catalysts bearing different metal loadings, respectively. Homogeneous counterparts, MoO2 VIN and WO2 VIN, as well as randomly ligandgrafted heterogeneous analogues, MoO2 VIG and WO2 VIG, were also prepared for comparison. X-ray absorption fine structure (XAFS), pair distribution function (PDF) and UV–vis data demonstrate that MoO2 VIT and WO2 VIT adopt a more solution-like bis(8-quinolinol) coordination environment than MoO2 VIG and WO2 VIG, respectively. Correspondingly, the templated MoVI and WVI catalysts show superior performances to their randomly grafted counterparts and neat analogues in the epoxidation of cyclooctene. It is found that the representative MoO2 VIT-10% catalyst can be recycled up to five times without significant loss of reactivity, and heterogeneity test confirms the high stability of MoO2 VIT-10% catalyst against leaching of active species into solution. The homogeneity of the discrete bis(8-quinolinol) metal spheres templated on SBA-15 should be responsible for the superior performances.

  18. Theoretical investigation of a blue hydroxyquinaldine-based aluminum(III) complex

    The absorption and light-emitting properties of a blue aluminum complex are investigated theoretically. The complex is bis(8-hydroxyquinolinolato) aluminum hydroxide [Al(Mq)2OH] and emits at about 485 nm. Very bright organic light-emitting diodes can be fabricated from Al(Mq)2OH with a maximum luminance of about 14 000 cd/m2. The geometry, bonding, and frontier orbitals are examined in details by self-consistent Hartree-Fock method and by density functional theory. Computational results indicate that the peak emission is mainly determined by the 2-methyl-8-quinolinol group and is independent of the hydroxide group. The computed absorption and emission gaps are in good agreement with experimentally determined values

  19. Determination of U(VI) using novel reagent by extractive spectrophotometry

    A simple and spectrophotometric method for the determination of U(VI) using a 5-(4-pyridyl azo)-8-quinolinol (PAQ) is developed the reagent was synthesized and used for extraction of uranium. At pH 7.0 ±0.2 uranium forms a yellowish orange colored complex with PAQ, which was then quantitatively extracted from chloroform showing maximum absorbance at wavelength of 485 nm. The proposed method obeys Beer's law in the range of 0.2-10.0 μg ml-1. Molar absorptivity and Sandelson's sensitivity of extracted species was calculated to be 1.325x104 lmol-1 cm-1 and 0.421 x10-4 μg cm-2 respectively. The method was applied for the determination of uranium in food and plant samples. It was found that the newly developed method is competent to those of standard methods. (author)

  20. Recognizing acute health effects of substitute fungicides: are first-aid reports effective?

    Teschke, K; Hertzman, C; Wiens, M; Dimich-Ward, H; Hershler, R; Ostry, A; Kelly, S J

    1992-01-01

    Recently, many British Columbia sawmills stopped using traditional chlorophenate anti-sapstain fungicides and substituted 2-(thiocyanomethylthio) benzothiazole (TCMTB) and copper-8-quinolinolate (Copper 8). We conducted a cross-sectional study with two aims: to ascertain which acute health effects, if any, were associated with the use of the substitute fungicides; and to determine the effectiveness of first-aid records as a means of detecting acute health outcomes. Workers in five coastal sawmills were asked to complete a self-administered questionnaire about symptoms considered potentially related and unrelated to fungicide exposure, and about injuries commonly reported in sawmills. In addition, we collected first-aid records from the mills, and asked senior workers to estimate the duration of exposure to fungicides for each job. Symptoms found to be consistently elevated in TCMTB mills included dry skin around the eyes, blood-stained mucus from the nose, nose bleed, peeling skin, burning or itching skin, and skin redness or rash. No symptoms were consistently elevated in the Copper 8 mills. Symptoms related to TCMTB exposure were recorded only 12 times in first-aid logs during the study period (versus 335 questionnaire self-reports). This low symptom-recording frequency may be a function of established patterns of first-aid use in which illness symptoms are reported less frequently than injuries. PMID:1585948

  1. A water-in-oil emulsion containing Kelex-100 for the speciation analysis of trace heavy metals in water

    A water-in-oil (w/o) emulsion containing Kelex-100 (7-dodecenyl-8-quinolinol) and Span-80 (sorbitan monooleate, non-ionic surfactant) was ultrasonically prepared from 1.0 mol l-1 hydrochloric acid and a (1 + 3) mixture of toluene and n-heptane. The resulting emulsion was gradually injected into water sample and dispersed as numerous tiny globules (0.01-0.1 mm in diameter). Dissolved inorganic species (free metal species) of heavy metals (e.g., Fe, Co, Cu, Cd, and Pb) were selectively transported through the oil layer into the internal aqueous phase of the emulsion, leaving other species, such as humic complexes and suspended particles (larger than 1 μm), in the sample solution. After collecting the dispersed emulsion globules, they were demulsified and the heavy metals in the segregated aqueous phase were determined by graphite-furnace atomic absorption spectrometry. The emulsion-based separation method allowed the selective collection of free metal species with a high concentration factor of 100, whereas the conventional solvent extraction did not offer such discrimination. This unique property of the emulsion method was successfully applied to the selective determination of free species of heavy metals in fresh water samples

  2. Tetrakis(5,7-dimethylquinolin-8-olato-κ2N,Ohafnium(IV dimethylformamide disolvate

    Andreas Roodt

    2011-10-01

    Full Text Available In the title compound, [Hf(C11H10NO4]·2C3H7NO, the HfIV atom is coordinated by four N,O-donating bidentate 5,7-dimethyl-8-quinolinolate (Ox− ligands arranged to give a distorted square-antiprismatic coordination polyhedron. The average Hf—O and Hf—N distances are 2.098 and 2.298 Å, respectively, and the average O—Hf—N bite angle is 70.2°. The crystal packing is controlled by π–π interactions between Ox− ligands of neighbouring molecules, giving rise to a three-dimensional supramolecular grid network. The interplanar distances vary from 3.441 (1 to 3.509 (1 Å, while the centroid–centroid distances vary from 3.688 (2 to 3.759 (12 Å. A non-classical C—H...O hydrogen bond is observed between the complex and one of the solvate molecules.

  3. Spectrophotometric catalytic determination of small amounts of rhenium in mineralized rocks and molybdenite

    Simon, F.O.; Grimaldi, F.S.

    1962-01-01

    Rhenium is determined by spectrophotometry of the tellurium sol formed by the reduction of tellurate by stannous chloride under the catalytic influence of rhenium. A detailed investigation of the conditions for high sensitivity and stability at lowest concentration levels of rhenium is presented as well as the behavior of 26 ions. The method is applied to the determination of some tenths of 1 p.p.m. or more of rhenium in a 1-mg. aliquot of mineralized rocks, mixtures of molybdenite and rocks, and molybdenite concentrates. The practical quantity limit of detection is 2 ?? 10-10 gram of rhenium. Samples are decomposed with a mixture of CaO, CaCl2, and MgO. On leaching, most constituents of the sample are precipitated either as calcium salts or hydroxides, except for rhenium and a small amount of molybdenum which pass into the filtrate. Residual molybdenum is removed by extraction with 8-quinolinol in chloroform. Better than 95% recoveries are obtained with two fusions with flux.

  4. Photoisomerization and structural dynamics of two nitrosylruthenium complexes: a joint study by NMR and nonlinear IR spectroscopies.

    Wang, Jianru; Yang, Fan; Zhao, Yan; Yu, Pengyun; Qiao, Xiaoyan; Wang, Jianping; Wang, Hongfei

    2014-11-21

    In this work, the photoisomerization and structural dynamics of two isomeric nitrosylruthenium(ii) complexes [Ru(OAc)(2cqn)2NO] (H2cqn = 2-chloro-8-quinolinol) in CDCl3 and DMSO are examined using NMR and IR spectroscopic methods. The two N atoms in the 2cqn ligand are in trans position in the synthesized cis-1 isomer, while they are in cis position in the cis-2 isomer. Kinetics monitored by NMR spectroscopy shows that the rate constant of photoisomerization from cis-2 to cis-1 isomer depends on the wavelength of irradiation and solvent polarity; it proceeds faster on irradiating near the absorption peak in the UV-Vis region, and also in more polar solvents (DMSO). Density functional theory computation indicates that the peculiarity of [Ru(ii)-NO(+)] group affects the structure and reactivity of the nitrosylruthenium complexes. Using the nitrosyl stretching (νNO) to be vibrational probe, the structural dynamics and structural distributions of the cis-1 and cis-2 isomers are examined by steady-state linear infrared and ultrafast two-dimensional infrared (2D IR) spectroscopies. The structural and photochemical aspects of the observed spectroscopic parameters are discussed in terms of solute-solvent interactions for the two nitrosylruthenium complexes. PMID:25285659

  5. A rare earth alloy as a synthetic reagent: contrasting homo metallic rare earth and hetero bimetallic outcomes

    Deacon, G.B.; Forsyth, C.M.; Junk, P.C.; Leary, S.G. [Monash Univ., School of Chemistry, Clayton (Australia)

    2006-04-15

    Reaction of LaNi{sub 5} with 2,2'-dipyridyl-amine (HNpy{sub 2}) at 170 C under vacuum gave crystals of dimeric [La(Npy{sub 2}){sub 3}]{sub 2} as a previously unknown eight-coordinate isomer (1a) (two {mu}-{eta}{sup 2}:{eta}{sup 2} and two terminal chelating (Namide,Npy) Npy{sub 2} ligands), which reverts to the known ten coordinate isomer (1b) on recrystallization from THF/PhMe, thereby establishing linkage isomerism of a [Ln(Npy{sub 2}){sub 3}]{sub 2} complex for the first time. Reaction of 8-hydroxyquinoline (HOQ) with excess LaNi{sub 5} alloy at 190 C resulted in extraction of both metals and the formation of hetero-bimetallic [Ni{sub 2}La(OQ){sub 7}] (2). The trinuclear complex has two terminal, fac-octahedral nickel(II) sites, each bound to three chelating 8-quinolinolate anions which bridge through the oxygen atoms to the lanthanum(III) centre. The eight-coordinate lanthanum environment is completed by a chelating OQ ligand. (authors)

  6. Synthesis and characterisation of 8-hydroxyquinoline-bovine serum albumin conjugates as metal ion chelating proteins

    A derivative of 8-hydroxyquinoline (8-quinolinol, oxine) with a linking bridge containing a carboxylic group was covalently coupled to bovine serum albumin by the N-hydroxysuccinimide method to obtain stable monomeric conjugates with oxine to protein mole ratios up to 37. These conjugates were characterised spectrophotometrically and their complexation properties were confirmed by spectral analysis with and without the addition of Al(III), Cd(II), Co(II), Cu(II), Hg(II), Mn(II), Ni(II), Pb(II), V(IV), U(VI) and Zn(II) ions added. The maximum number of ions bound by these chelating proteins was determined spectrophotometrically by titration with metal ions at pH 6.0. The conjugates with a substitution ratio (moles of 8-hydroxyquinoline bound/mole of albumin) less than about 8 showed 1:1 binding with metal ions, while conjugates with higher substitution ratios were able to complex with 2:1 ratio of 8-hydroxyquinoline to metal ion. Association and dissociation kinetics of complexation with copper(II) ions showed a complex mechanism. The spectral and binding properties of these metal ion-binding proteins confirm that the coupling of the 8-hydroxyquinoline derivative to bovine serum albumin gives stable, water soluble, macromolecular chelating agents that retain the complexing ability of the original ligand. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  7. Microchemical chip technology and nuclear energy. To develop new analytical system for process control in reprocessing plant

    A feasibility study for two years has been done to apply micro-chemical chip technology to nuclear fuel reprocessing plant. Desktop-sized thermal lens microscope (DT-TLM) combined with integrated glass ship was examined in order to find a rapid and sensitive analytical method. A laser-beam is split into two beams, one as the reference while the other to be absorbed in a small quantity of sample solution in a cell with short optical-path length. The solution, on absorbing laser photons, increases in temperature accompanied with change in refractive index, which can be detected by using thermal lens microscope. After examinations of Co-complexes in the presence of 10-6 M Cu ions by using micro chip-extraction behavior from aqueous phase to chloroform organic phase, and of U(VI) solutions in 3M nitric acid with added 8-quinolinol and others to develop optical density at absorbing wavelength, the author concluded that the system may be applicable for the practical analysis of U(VI) and H+ in the spent fuel reprocessing plant. (S. Ohno)

  8. Adsorption properties of gold(III), molybdenum(VI) and vanadium(V) on surface of green-teaparticles in aqueous solutions

    The adsorption properties of Au(III), Mo(VI) and V(V) ions on surface of the Japanese green-tea (powder tea) particles were examined by measurements of the adsorption percentage and by plotting the adsorption isotherm curves in aqueous solutions of pH 1∼6. The powder tea was treated with formaline in a dilute sulfuric acid. A 100 ml sample solution containing Au, Mo and/or V was mixed with the treated tea (0.1 or 0.5 g for usual use) under stirring for 30 min. The solution was then centrifuged and the concentrations of Au(III), Mo(VI) and V(V) ions in the supernatant solution were determined with the atomic absorption spectrometer. Au and Mo at pH 1∼6, and V at pH 3∼6 were adsorbed over 80% on the tea. The maximum adsorption amounts under the conditions were determined by the isotherm and Langmuir plots to be 23, 12 and 3.5 mg g-1 for Au, Mo and V, respectively. It was found that 50μg Au, 200μg Mo, and 150μg V in a 100 ml solution containing 10 or 30 g Zn(NO3)2·6H2O were quantitatively adsorbed on 0.1 g of the tea. Effect of NaCl, Na2SO4, Na2C2O4, 8-quinolinol, 1, 10-phenanthroline and EDTA (Na2[H2edta]) on the adsorbability of Au, Mo and V was examined. The adsorption percentage of Au did not change at all by addition of anyone of them. On the other hand, adsorption of Mo and V was seriously inhibited by addition of EDTA, and that of Mo was remarkably inhibited by addition of 1,10-phenanthroline. (author)

  9. Small-molecule quinolinol inhibitor identified provides protection against BoNT/A in mice.

    Padma Singh

    Full Text Available Botulinum neurotoxins (BoNTs, etiological agents of the life threatening neuroparalytic disease botulism, are the most toxic substances currently known. The potential for the use as bioweapon makes the development of small-molecule inhibitor against these deadly toxins is a top priority. Currently, there are no approved pharmacological treatments for BoNT intoxication. Although an effective vaccine/immunotherapy is available for immuno-prophylaxis but this cannot reverse the effects of toxin inside neurons. A small-molecule pharmacological intervention, especially one that would be effective against the light chain protease, would be highly desirable. Similarity search was carried out from ChemBridge and NSC libraries to the hit (7-(phenyl(8-quinolinylaminomethyl-8-quinolinol; NSC 84096 to mine its analogs. Several hits obtained were screened for in silico inhibition using AutoDock 4.1 and 19 new molecules selected based on binding energy and Ki. Among these, eleven quinolinol derivatives potently inhibited in vitro endopeptidase activity of botulinum neurotoxin type A light chain (rBoNT/A-LC on synaptosomes isolated from rat brain which simulate the in vivo system. Five of these inhibitor molecules exhibited IC(50 values ranging from 3.0 nM to 10.0 µM. NSC 84087 is the most potent inhibitor reported so far, found to be a promising lead for therapeutic development, as it exhibits no toxicity, and is able to protect animals from pre and post challenge of botulinum neurotoxin type A (BoNT/A.

  10. Stereo-selectivity of human serum albumin to enantiomeric and isoelectronic pollutants dissected by spectroscopy, calorimetry and bioinformatics.

    Ejaz Ahmad

    Full Text Available 1-naphthol (1N, 2-naphthol (2N and 8-quinolinol (8H are general water pollutants. 1N and 2N are the configurational enantiomers and 8H is isoelectronic to 1N and 2N. These pollutants when ingested are transported in the blood by proteins like human serum albumin (HSA. Binding of these pollutants to HSA has been explored to elucidate the specific selectivity of molecular recognition by this multiligand binding protein. The association constants (K(b of these pollutants to HSA were moderate (10(4-10(5 M(-1. The proximity of the ligands to HSA is also revealed by their average binding distance, r, which is estimated to be in the range of 4.39-5.37 nm. The binding free energy (ΔG in each case remains effectively the same for each site because of enthalpy-entropy compensation (EEC. The difference observed between ΔC(p (exp and ΔC(p (calc are suggested to be caused by binding-induced flexibility changes in the HSA. Efforts are also made to elaborate the differences observed in binding isotherms obtained through multiple approaches of calorimetry, spectroscopy and bioinformatics. We suggest that difference in dissociation constants of pollutants by calorimetry, spectroscopic and computational approaches could correspond to occurrence of different set of populations of pollutants having different molecular characteristics in ground state and excited state. Furthermore, our observation of enhanced binding of pollutants (2N and 8H in the presence of hemin signifies that ligands like hemin may enhance the storage period of these pollutants in blood that may even facilitate the ill effects of these pollutants.