Binding properties of a polyclonal antibody directed towards lead complexes

A previously described conjugate of 8-hydroxyquinoline and bovine serum albumin was complexed with lead(II), (8-hydroxyquinoline to metal ion ratio 2:1) and used as an immunogen to produce polyclonal antibodies against lead in chickens. Antibodies obtained from a first blood sample during a standard immunisation procedure showed very promising features (dynamic range of the assay was 1 to 1000 ng l(-1)). Nevertheless, proceeding with the immunisation caused a complete loss of the recognition of the complex. A modified brief immunisation procedure was carried out and, in this case, the immunogen proved to be sufficiently stable in vivo to produce antibodies that selectively bound to the lead(II) complex (in the same 2:1 ratio used as an immunogen). Since the antiserum obtained cannot reach the same performance levels as the first one, standard curves were obtained by adding the free 8-hydroxyquinoline to the solution, which enables 2:1 complexes to be more easily formed. Cross-reactivity and dependence from buffer were investigated, showing at least 10-fold lower binding to non-target divalent metal ions compared to lead(II). MES buffer (pH = 6.0) gave more sensitive but very imprecise curves, whereas Tris (pH = 8.5) allows higher precision but lower sensitivity to be observed.     

Preparation and study of new poly-8-hydroxyquinoline chelators for an anti-Alzheimer strategy

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.     

Synthesis, magnetic, spectral, and antimicrobial studies of Cu(II), Ni(II) Co(II), Fe(III), and UO2(II) complexes of a new Schiff base hydrazone derived from 7-chloro-4-hydrazinoquinoline

A new hydrazone ligand, HL, was prepared by the reaction of 7-chloro-4-hydrazinoquinoline with o-hydroxybenzaldehyde. The ligand behaves as monoprotic bidentate. This was accounted for as the ligand contains a phenolic group and its hydrogen atom is reluctant to be replaced by a metal ion. The ligand reacted with Cu(II), Ni(II), Co(II), Fe(III), and UO2(II) ions to yield mononuclear complexes. In the case of Fe(III) ion two complexes, mono- and binuclear complexes, were obtained in the absence and presence of LiOH, respectively. Also, mixed ligand complexes were obtained from the reaction of the metal cations Cu(II), Ni(II) and Fe(III) with the ligand (HL) and 8-hydroxyquinoline (8-OHqu) in the presence of LiOH, in the molar ratio 1:1:1:1. It is clear that 8-OHqu behaves as monoprotic bidentate ligand in such mixed ligand complexes. The ligand, HL, and its metal complexes were characterized by elemental analyses, IR, UV-vis, mass, and 1H NMR spectra, as well as magnetic moment, conductance measurements, and thermal analyses. All complexes have octahedral configurations except Cu(II) complex which has an extra square-planar geometry, while Ni(II) mixed complex has also formed a tetrahedral configuration and UO2(II) complex which formed a favorable pentagonal biprymidial geometry. Magnetic moment of the binuclear Fe(III) complex is quite low compared to calculated value for two iron ions complex and thus shows antiferromagnetic interactions between the two adjacent ferric ions. The HL and metal complexes were tested against one stain Gram positive bacteria (Staphylococcus aureus), Gram negative bacteria (Escherichia coli), and fungi (Candida albicans). The tested compounds exhibited higher antibacterial acivities.     

Massenspektren von Metallkomplexen des 2-n-Butyl-8-Hydroxychinolins

The fragmentation pattern of metal complexes of 2-butyl-8-hydroxyquinoline depends essentially upon the ability of the metal ion to absorb an electron, i.e. to exist in a stable monovalent form. In this case the main fragment is formed by loss of a molecule of 2-n-butyl-8-hydroxyquinoline, otherwise an ethyl radical is eliminated.     

Thermal decomposition of 8-hydroxyquinoline complexes with aluminium,cobalt, manganese and nickel

The conditions of thermal decomposition of aluminium(III), cobalt(II), manganese(II) and nickel(II) 8-hydroxyquinoline complexes have been studied by TG-DSC analysis. The thermal decomposition of these complexes has two stages: dehydration and loss of 8-hydroxyquinoline. The final solid product is an oxide.     

2-乙烯基氟代苯-8-羟基喹啉锌配合物的合成及光学性能研究

设计合成了2种新型的含不同氟原子数的8-羟基喹啉衍生物配体:(E)-2-[2-(2-氟代苯基)乙烯基]-8-羟基喹啉(4a)和(E)-2-[2-(五氟苯基)乙烯基]-8-羟基喹啉(4b)及其相应的锌配合物5a和5b,利用1H NMR、IR、MS、元素分析确认了产物结构。通过紫外滴定模拟了金属锌与配体4a和4b的配位过程,测定了其在二甲基甲酰胺(DMF)溶液中的荧光性质。荧光光谱显示:配体4a和4b在DMF溶液中的λmax分别为505 nm(蓝绿色)和517 nm(绿色),配合物5a和5b的λmax分别为559 nm(青绿色)和599 nm(黄色),配位后体系共轭程度增大,荧光光谱发生明显的红移。而且随着取代氟原子的增加,配体和配合物的荧光光谱也发生明显的红移。荧光光谱显示氟原子取代数量的改变可以调控8-羟基喹啉锌配合物的发光性质。     

A novel decanuclear Co(II) cluster with adamantane-like metallic skeleton supported by 8-hydroxyquinoline and in situ formed CO3(2-) anions

A novel decanuclear Co(II) cluster, [Co(10)(Q)(12)(μ(6)-CO(3))(4)]·2.5DMF (1) (Q = 8-hydroxyquinoline), has been synthesized under solvothermal conditions and characterized by powder XRD, TGA and IR spectroscopy. Single-crystal X-ray diffraction analysis shows that 1 represents a new type of decanuclear cobalt cluster with an approximate supertruncated tetrahedral shape coordinated with coexisted Q ligands and in situ formed μ(6)-bridging CO(3)(2-) anions. Meanwhile, 1 is the largest aggregate in metal-Q coordination chemistry. Another distinguishing feature of 1 is the adamantane-like metallic skeleton with point symbol {6(3)}(2){6}(3), which is observed in the polynuclear metal complexes for the first time. Furthermore, it is considered that the in situ formed CO(3)(2-) anions have a crucial effect on the formation of the resultant unexpected polynuclear structures. The magnetic studies show that antiferromagnetic (AF) interactions exist within 1.     

A green solventless temperature-assisted homogeneous liquid–liquid microextraction method based on 8-hydroxyquinoline simultaneously as complexing agent and extractant for preconcentration of cobalt and nickel from water and fruit juice samples

A green, simple, rapid and efficient solventless temperature-assisted homogeneous liquid-liquid microextraction based on 8-hydroxyquinoline as complexing agent and extractant, followed by flame atomic absorption spectrometry was developed for the extraction, enrichment, and determination of trace amounts of nickel and cobalt in aqueous samples. For this purpose, first, a specified amount of 8-hydroxyquinoline is added to the analytes solution. Then the temperature of the solution is increased to melt 8-hydroxyquinoline and form a homogeneous solution. Then, it is cooled to room temperature and a cloudy solution is formed due to decreasing 8-hydroxyquinoline solubility. The solution is then centrifuged, and 8-hydroxyquinoline particles containing the produced complexes (8-hydroxyquinoline-cation) are collected at the bottom of the tube. They are removed and dissolved in a suitable solvent and injected to the detection system. The main parameters affecting the extraction efficiency, such as the amount of 8-hydroxyquinoline, solvent nature, pH, extraction temperature and heating time were investigated. Under optimum conditions, linear ranges for Co(II) and Ni(II) were 1–100 and 0.5–75 µg L^?1, respectively. Relative standard deviations for intra- and inter-day precisions calculated from six repeated determinations at three different concentrations of Co(II) and Ni(II) were ≤5.2 %. Moreover, the obtained detection limits of the analytes were 0.35 and 0.20 µg L^?1 for Co(II) and Ni(II), respectively. The accuracy of the developed procedure was checked by analysing SPS-WW2 Batch 108 water as a certified reference material. Finally, the developed method was successfully applied for the determination of the selected cations in water and fruit juice samples.     

3-[2-(8-羟基喹啉基)-乙烯基]-N-芳基咔唑及其金属配合物的合成和光电性能研究

设计合成了3-[2-(8-羟基喹啉基)-乙烯基]-N-对甲苯基咔唑(8)和3-[2-(8-羟基喹啉基)-乙烯基]-N-对甲氧苯基咔唑(9)及其金属锌配合物(10和11), 用UV-Vis, FTIR, ESI-MS, FAB-MS, ¹H NMR和元素分析确认了化合物的结构. 热重分析实验结果表明, 金属锌配合物(10和11)有很好的热稳定性, 这对真空蒸镀制电致发光器件是有益的. 金属锌配合物组装成有机单层发光器件的结构为ITO/Organ layer(50 nm)/Al(100 nm), 其荧光发射峰分别位于592和583 nm, 为稳定的黄色光. 这两个发光器件的最大亮度分别为489和402 cd/m², 最大电流效率分别为0.41和1.81 cd/A. 电致发光研究表明, 通过化学修饰8-羟基喹啉的2-位取代基可以改变这两个金属锌配合物的电致发光性能.     

Determination of UO2(II), Th(IV) and Ce(III) Complexes Formed with Halogen and Nitro Derivatives of 8-Hydroxyquinoline

Proton-ligand stability constants for some iodo and nitro derivatives of 8-hydroxyquinoline were determined by Calvin Bjerrum potantiometric method. The stability constants of the corresponding chelates with UO₂ (II), Th(IV) and Co(III) were studied potentiometrically at 25 °C by applying Irving-Rossotti computing method. The complexes of the nitro-substituted ligands were less stable than the corresponding complexes of the unsubstituted ligands. The stability constants of metal-ligands depend on the ionic radii and ionic charge of metals and also they decrease with steric repulsions of the nitro groups.     

Stability constants of uranium(VI) and thorium(IV) complexes formed with 8-hydroxyquinoline and its 5-sulfonic acid derivative

In this study, the stability constants of uranium(VI) and thorium(IV) complexes formed with 8-hydroxyquinoline (8-HOQ) and its 5-sulfonic acid (8-HOQ-5-SO₃H) derivative have been determined using the Irving-Rossotti method, computing the Calvin-Bjerrum pH-titration data. As a result, it is determined that the thorium(IV) complexes are considerably more stable than the corresponding uranium(VI) complexes. On the other hand, the complexes formed between 8-HOQ-5-SO₃H and uranium(VI) or thorium(IV) are less stable than the corresponding 8-HOQ complexes.     

First raw transition metal complexes of salicylidene and 2-hydroxy-1-naphthylidene-N-cyanoacetohydrazone

Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes of salicylidene-N-cyano-acetohydrazone H2L1 and 2-hydroxy-l-naphthylidene-N-cyanoacetohydrazone H2L2 have been prepared in ethanolic solution and characterized by analytical, spectral, magnetic susceptibility, molar conductivity and TGA measurements. The analytical data show that all the complexes derived from H2L1 and H2L2 are formed in molar ratios 1M:2L, except the complexes of Mn(II), Co(II) and Cu(II) acetates of H2L2 and the complexes of Mn(II), Co(II) and Ni(II) acetates and CuCl2 of H2L1 are formed in 1:1 molar ratios. The conductance data show that all metal complexes are non-electrolytes. Electronic absorption spectra and magnetic susceptibility measurements proved that the prepared complexes have octahedral configuration except [Co(HL2)OAc] which has tetrahedral structure. The ligand field parameters were calculated for the Co(II) and Ni(II) complexes and the data show that the covalent character of the metal ligand sigma-bond is low. The ESR parameters of the Cu(II) complexes at room temperature were calculated. Thermal TGA for some solid complexes are reported.     

Synthesis,characterization, and the antimicrobial and anthelmintic activities of some metal complexes with a new Schiff base 3-[(Z)-5-amino-1,3,3-trimethyl cyclohexylmethylimino]-1,3-dihydroindol-2-one

The complexes of Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II), dioxouranium(VI), and Th (IV) with a new Schiff base, 3-[(Z)-5-amino-1,3,3-trimethyl cyclohexylmethylimino]-1,3-dihydroindol-2-one formed by the condensation of isatin (Indole-2.3-dione) with isophoronediamine(5-amino-1,3,3-trimethyl-cyclohexane methylamine) (IPDA) was synthesized and characterized by microanalysis, conductivity, UV-visi-ble, FT-IR, 1 H NMR,TGA, and magnetic susceptibility measurements. All the complexes exhibit 1: 1 metal to ligand ratio except for the dioxouranium(VI) and thorium(IV) complexes, where the metal: ligand stoichiometry is 1: 2. The spectral data revealed that the ligand acts as monobasic bidentate, coordinating to the metal ion through the azomethine nitrogen and carbonyl oxygen of the isatin moiety. Tetrahedral geometry for Co(II), Ni(II), Zn(II), Cd(II), and Hg(II) complexes, square planar geometry for Cu(II) complexes, and the coordination numbers 6 and 8 for UO₂(VI) and Th(IV) complexes, respectively, are proposed. Both the ligand and the metal complexes were screened for their antibacterial activity against Bacillus subtilis, Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Pseudomonas aeruginosa, and the complexes are more potent bactericides than the ligand. The anthelmentic activity of the ligand and its complexes against earthworms was also investigated. This article was submitted by the authors in English.     

Study on preparation and fluorescence characteristic of the (Alqx)/Al2O3 nano colloids

Alumina 8-hydroxyquinoline complexes (Alqx)/Al2O3 nano colloids have been successfully prepared by focused, pulsed laser ablation at the interface of solid Al2O3 and a flowing liquid containing 8-hydroxyquinoline (Q) and one of two polymers (polystyrene, PS, and polymethyl methacrylate, PMMA). Three factors influenced the luminescence of the (Alqx)/Al2O3 nano colloids. The first factor was whether the 8-hydroxyquinoline was added before or after laser ablation. The second factor was if the reaction medium consisted of (1) Q dissolved in ethanol, (2) Q dissolved in cyclohexane containing PS, or (3) Q dissolved in ethyl acetate containing PMMA. The third factor affecting luminescence was the age of the colloids. The (Alqx)/Al2O3 nano colloid product was characterized by transmission electron microscopy (TEM), ultraviolet visible spectroscopy (UV-vis), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and fluorescence spectroscopy. The product from all three-reaction media luminesced when irradiated with ultraviolet light. The product formed in cyclohexane containing PS gave the greatest luminescence, followed by the product formed in ethanol, and the product formed in ethyl acetate containing PMMA gave the smallest luminescence. The luminescence mechanism is similar to that of Alq3.     

Extraction of tungsten with 8-hydroxyquinoline and some of its derivatives

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.     

Stereochemistry of new nitrogen containing heterocyclic compounds.; X. Supramolecular structures and stereochemical versatility of polymeric complexes

New polymeric complexes of Cu(II), Co(II), Ni(II) and UO2(II) with 5-(2(1)-carboxyphenylazo)-8-hydroxyquinoline (LH2) have been prepared and characterized on the basis of analytical, magnetic, 1H NMR, EPR and electronic spectral studies. Tentative structures for the polymeric complexes are proposed. The important infrared (IR) bands and the main 1H NMR signals are assigned and discussed relative to the molecular structure. EPR spectrum of copper(II) complex has been studied with a view to assigning their stereochemistries. Various EPR parameters have been calculated. Each metal has six-coordinates in an octahedral environment. The ligand acts as a dibasic (bis-bidentate chelating agent coordinating through CN, N=N, COOH and OH groups by replacement of a proton from the two latter groups. Considerable interest has also been focused on the synthesis of the azo compounds and its polymeric metal complex due to its wide potential applications. The thermal decomposition behavior of the complexes is also discussed.     

Synthesis and characterization of iron(III), manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) complexes of salicylidene-N-anilinoacetohydrazone (H2L1) and 2-hydroxy-1-naphthylidene-N-anilinoacetohydrazone (H2L2)

Salicylidene-N-anilinoacetohydrazone (H(2)L(1)) and 2-hydroxy-1-naphthylidene-N-anilinoacetohydrazone (H(2)L(2)) and their iron(III), manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) complexes have been synthesized and characterized by IR, electronic spectra, molar conductivities, magnetic susceptibilities and ESR. Mononuclear complexes are formed with molar ratios of 1:1, 1:2 and 1:3 (M:L). The IR studies reveal various modes of chelation. The electronic absorption spectra and magnetic susceptibility measurements show that the iron(III), nickel(II) and cobalt(II) complexes of H(2)L(1) have octahedral geometry. While the cobalt(II) complexes of H(2)L(2) were separated as tetrahedral structure. The copper(II) complexes have square planar stereochemistry. The ESR parameters of the copper(II) complexes at room temperature were calculated. The g values for copper(II) complexes proved that the Cu-O and Cu-N bonds are of high covalency.     

Relative stabilities of metal complexes of 4-(2-pyridylazo)resorcinol and 4-(2-thiazolylazo)resorcinol

The stability constants of 1:1 complexes of 4-(2-pyridylazo)resorcinol (PAR) and 4-(2-thiazolylazo)resorcinol (TAR) with Mn(II), Ni(II), Cu(II) and Zn(II) have been determined spectrophotometrically at μ = 0.1 and 25°C. The method is based on indirect estimation of the protonated and normal complexes by measuring the ligand absorption peak. Both protonated and normal complexes of these metals with PAR are more stable than those with TAR. The reverse order was previously observed for the pronated complexes of the lanthanides(III). The different behaviour of the 3d transition metals(II) compared to the lanthanides(III) is discussed. The proton dissociation constants of the protonated complexes of PAR or TAR with various metals are also discussed.     

Determination of metals at trace levels via pre-column derivatization and nonpolar stationary-phase high-performance liquid chromatography with n-butyl-2-naphthylmethyldithiocarbamate complexes

A new, very stable dithiocarbamate, bis(n-butyl-2-naphthylmethyldithiocarbamate) zinc(II), has been synthesized and its use in trace metal determination by high-performance liquid chromatography (h.p.l.c.) has been investigated. Metal complexes of this ligand are thermodynamically stable and kinetically inert at the 1 × 10^-8 M level. Various metal complexes including nickel(II), iron(III), copper(II), mercury(II), and cobalt(II) have been “baseline” separated by nonpolar stationary-phase h.p.l.c. The detection limits are about 1–2 ng with a variable-wavelength absorbance detector.     

Surface layer-by-layer chemical deposition reaction for thin film formation of nano-sized metal 8-hydroxyquinolate complexes

The feasibility of a novel and simple layer-by-layer chemical deposition method for the preparation of nano-sized metal 8-hydroxyquinolate complexes has been investigated and reported. Uniform nanocrystalline films have been synthesized via dipping a substrate alternately in metal ion solution followed by ligand solution. The stoichiometry of the as-grown anhydrous Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) complex crystals were confirmed from the metal analysis and molar stoichiometric ratio of metal ion to 8-hydroxyquinoline. This was characterized as 1:2 for the Co(II), Ni(II), Cu(II) and Zn(II)–quinolate complexes. The Fe(III)–quinolate thin film was found to exhibit a 1:3 ratio. Electron impact-mass spectra (EI-MS) of all the synthesized thin film metal quinolate complexes were recorded and the results refer to the existence of the molecular ion peak at the corresponding m/z values. Confirmation of such stoichiometric 1:2 and 1:3 ratios were also evident from the (EI-MS) study. The deposited thin films were also subjected to analysis by a scanning electron microscope (SEM) and a particle size ?50 nm was detected. FT-IR and UV–Vis spectroscopy were further used to confirm the structure of the metal 8-hydroxyquinolate complexes. Thermal gravimetric analysis (TGA) was also used to follow up the possible thermal decomposition steps and to calculate the thermodynamic parameters of the nano-sized metal complexes.