Oxine Derivatives Research Articles

A Quick Responsive Chitosan‐Oxine Based Thin Film to Recognize and Remove Zn2+ Ions from Potable Water

AbstractThrough the functionalization of chitosan (CS) with an oxine derivative, 8‐hydroxy‐2‐methyl‐quinoline5,7‐ sulfonyl chloride (HQSC), a thin film was prepared (CS‐HQSC). The film can recognize and adsorb Zn2+ ions from the aqueous samples. The sensor performances were characterized by UV‐Visible and fluorescence spectroscopic analysis. The weakly fluorescent thin film becomes highly fluorescent in the presence of Zn2+ ions. The solution‐phase study of the functionalized material shows a 30‐fold fluorescence enhancement in the presence of Zn2+ ions. The chelation of Zn2+ ions with CS‐HQSC could be the reason for the fluorescence enhancement. The chelation restricts the excited‐state proton transfer in the quinoline ring and facilitates chelation enhanced fluorescence. The sensor showed a linear detection of Zn2+ ions from 0.2 to 2 ppm, with the lowest detection limit of 0.08 ppm. The practical applicability studies of the sensor prove that the sensor film is quick responsive (30 seconds) and recyclable in acid solution. Also, the functionalized material CS‐HQSC shows 96 % removal of Zn2+ ions from the water samples.

Substituted oxines inhibit endothelial cell proliferation and angiogenesis

Two substituted oxines, nitroxoline (5) and 5-chloroquinolin-8-yl phenylcarbamate (22), were identified as hits in a high-throughput screen aimed at finding new anti-angiogenic agents. In a previous study, we have elucidated the molecular mechanism of antiproliferative activity of nitroxoline in endothelial cells, which comprises of a dual inhibition of type 2 human methionine aminopeptidase (MetAP2) and sirtuin 1 (SIRT1). Structure-activity relationship study (SAR) of nitroxoline offered many surprises where minor modifications yielded oxine derivatives with increased potency against human umbilical vein endothelial cells (HUVEC), but with entirely different as yet unknown mechanisms. For example, 5-nitrosoquinolin-8-ol (33) inhibited HUVEC growth with sub-micromolar IC(50), but did not affect MetAP2 or MetAP1, and it only showed weak inhibition against SIRT1. Other sub-micromolar inhibitors were derivatives of 5-aminoquinolin-8-ol (34) and 8-sulfonamidoquinoline (32). A sulfamate derivative of nitroxoline (48) was found to be more potent than nitroxoline with the retention of activities against MetAP2 and SIRT1. The bioactivity of the second hit, micromolar HUVEC and MetAP2 inhibitor carbamate 22 was improved further with an SAR study culminating in carbamate 24 which is a nanomolar inhibitor of HUVEC and MetAP2.

Synthesis of novel 5,7‐disubstituted 8‐hydroxyquinolines

Abstractmagnified imageSeven new 5,7‐disubstituted oxine derivatives have been synthesized via a Mannich reaction between a sec. amine (e.g. piperidine, pyrrolidine, morpholine, or dibenzylamine,) and 5‐cyano or 5‐azidomethyl‐8‐hydroxyquinoline, which were respectively obtained by nucleophilic displacement of 5‐chloromethyl‐8‐hydroxyquinoline by cyanide or azide anions. In all cases, a single product was isolated in medium to fair yield and characterized on the basis of 1H and 13C‐NMR, MS and IR spectrometric data. The X‐ray structure of the product obtained from 5‐cyanomethyl‐8‐hydroxyquinoline and piperidine is also reported.

Oxovanadium(IV) and oxovanadium(V) complexes relevant to biological systems

Different aspects of the coordination chemistry of oxovanadium(IV) and oxovanadium(V), relevant to the bioinorganic chemistry of vanadium, are presented. Some of the investigated complexes are good models for different aspects of the metabolism and detoxification of vanadium or for a better characterization and understanding of the structural and electronic peculiarities of the coordination spheres of VO 2+ and VO 2 + in biomolecules. Their structural, spectroscopic and magnetic properties are briefly discussed. The investigated systems include ligands such as reduced and oxidized glutathione, l-ascorbic acid, nucleotides and related systems, carbohydrates, phosphates, carboxylic acids, oxine derivatives and some others.

Comparison between thermal analysis and mass spectroscopic studies of uranyl oxinates

The 5,7-dichloro, 5,7-dibromo, 5,7-diiodo and 5,6-dinitro derivatives of oxine (ligandsL 1,−L 4) were used to prepare uranyl chelates (A 1–A 4). Thermal analysis (DTA) and mass spectroscopic studies were performed. The stoichiometries of the chelates were determined by elemental analysis, molecular weight determination applying an α-spectroscopic liquid scintillation counter and mass spectral measurements. The uranyl∶ligand ratios were found to be 1∶1 for A1, 1∶3 for A2, 1∶2 (monohydrate) for A3, and 1∶2 forA 4. The correlation between the thermal analysis and mass spectra was examined. The activation energy required for each step of thermal degradation of the ligands and chelates was calculated. The natures of most of the molecular ions obtained in the mass spectra were also explained.

Synergistic Extraction of Gallium(III) with 2-Ethylhexyl-Phosphonic Acid Mono-2-Ethylhexyl Ester in the Presence of Oxine Derivatives.

The synergistic extraction of gallium (III) with mixed extractants of 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (EHPNA) as the main extractant and four kinds of oxine derivatives as synergists diluted in toluene or n-heptane was examined. The synergists used were 8-hydroxyquinoline, 8-hydroxyquinaldine, 5-fluoro-8-hydroxyquinoline and 5-chloro-8-hydroxyquinoline. The extraction system using EHPNA and 8-hydroxyquinaidine did not show any synergistic effect. The order of magnitude of synergism was as follows; 5-chloro-8-hydroxyquinoline > 5-fluoro-8-hydyoxyquinoline > 8-hydroxyquinoline. The extraction reaction with mixed extractants can he reasonably interpreted based an the formation of three gallium complexes. The chemical effect of the substituent group of the oxine derivatives as synergists was small. The synergistic extraction mechanism of gallium (III) by the mixed extractants of EHPNA and the oxine derivatives can he related to concentration of the synergist in the organic solution, which is determined by its distribution ratio and acid dissociation constant.

Spontaneous abortions: more common among familial Alzheimer disease cases than sporadic cases : Z. Davanipour (Loma Linda University, USA), R. Sulkava (University of Kuopio, Finland), E. Sobel (University of Southern California, USA), T. Erkinjuntti (University of Helsinki, Finland)

Kelex 100, a commercially available alkylated oxine derivative, is shown to be effective, in purified form, for the simultaneous extraction of trace levels of Cd(II), Co(II), Cu(II), Mn(II), Ni(II), Pb(II), and Zn(II) from natural waters into toluene. The high lipophilicity of the extractant and its chelates affords large preconcentration factors in a single batch-extraction. Back-extraction with a small volume of nitric acid provides additional enrichment for subsequent determination of total (soluble) metal by graphite-furnace atomic-absorption spectrometry (GFAAS). Calibration with standard solutions can be used, which has advantages over the method of standard additions.

Multielement preconcentration of trace metals from natural waters by solvent extraction with an alkylated oxine derivative

Kelex 100, a commercially available alkylated oxine derivative, is shown to be effective, in purified form, for the simultaneous extraction of trace levels of Cd(II), Co(II), Cu(II), Mn(II), Ni(II), Pb(II), and Zn(II) from natural waters into toluene. The high lipophilicity of the extractant and its chelates affords large preconcentration factors in a single batch-extraction. Back-extraction with a small volume of nitric acid provides additional enrichment for subsequent determination of total (soluble) metal by graphite-furnace atomic-absorption spectrometry (GFAAS). Calibration with standard solutions can be used, which has advantages over the method of standard additions.

Synthesis and Characterization of Some New Derivatives of Dichloroniobium(V) Tricatecholate and Tripyrogallolate

Abstract Some new pseudohalide, oxine and amido derivatives of dichloroniobium(V) tricatecholate/tripyrogallolate1 were isolated and studied. These compounds of the general formula L2Nb(X) (where X = (OC6H40) (OC6H4OH), (O3C6H4OH) (03C6H5), L = N3 −, NCO−, NCS, CN−, C9H6NO− and NH2 −) are coloured solids. The compounds were characterized by chemical analysis and infrared spectral data.

Metal chelates in adsorption polarography I: Mo(VI) and derivatives of oxine

The formation of complexes between Mo(VI) and 8-hydroxy-quinoline (oxine) and four oxine derivatives were investigated by multiwavelength molecular absorption spectrometry, potentiometry, and polarography. The following pKOH- and pKNH- values of the ligands and logK211-values of the complexes MoO2(OH)2Lx− (x=1 or 2) were obtained at 25° C and an ionic strength of 1M(NaClO4): 5,7-dinitro8-hydroxyquinoline 4.59, <0, 14.50; 7-nitro-8-hydroxyquinoline-5-sulfonic acid 5.34, 0.41, 15.70; 7-iodo-8-hydroxyquinoline-5-sulfonic acid 6.98, 2.62, 17.65; 8-hydroxyquinoline-5-sulfonic acid 8.33, 4.13, 18.71; and 8-hydroxyquinoline 9.62, 5.28, 19.69. A good linearity was found between logK211 and the sum of the pK-values of the OH- and NH+-groups. The dependence of the peak current of Mo(VI)-determinations by adsorption polarography of the 7-nitro-8-hydroxyquinoline-5-sulfonate complex of Mo(VI) MoO(OH)3L− can quantitatively be described at pH 0.8–2 using the corresponding pK-values and the log K311 of 18.54±0.03, determined by polarography.

Studies on the Preparation and Characterization of some new Organometallic Derivatives of Dichloroniobium(V) Triphenoxide

Abstract Some new pseudohalide, oxine and amido derivatives of dichloroniobium(V) triphenoxide1 were prepared. The analytical data, conductance, infrared spectra and proton nmr spectra of the compounds are reported.

Spectroscopic investigation of adsorbed 7-(4-ethyl-1-methyloctyl)-8-quinolinol (kelex 100) and of its gallium(III) complex: Comparison with the behaviours observed in solvent extraction systems

The adsorption of a long hydrocarbon chain oxine derivative, 7-(4-ethyl-1-methyloctyl)-8-quinolinol, on the macromolecular Amberlite XAD-7 support is shown by FT-IR spectroscopy to be the result of only weak extractant-support interactions. It is also shown that the chelation ability of the extractant towards gallium(III) does not suffer from the presence of the solid support. Finally the stereochemistry ( fac or mer configuration) of the tris-7-(4-ethyl-1 -methyloctyl)-8-quinolinato gallium(III) complex formed either in solution in an organic diluent or on the support is discussed on the basis of 1H and 13C NMR and FIR data.

Study of the properties of a liquid ion exchanger adsorbed on a macroreticular resin

The adsorption and retention of the hydrocarbon chain oxine derivative 7-undecyl-8-hydroxyquinoline on a macroreticular resin, Amberlite XAD-7, was studied spectrometrically. The ability of the liquid ion exchange molecules to form chelates with metal cations was examined by ESR spectroscopy. The correlation of both allows a description of the observed adsorption mechanism.

Phenylbismuth(III) and triphenylbismuth(V) complexes with oxine derivatives. The crystal structure of chloro(2-methyl-8-quinolinolato)triphenylbismuth(V)

The complexes Ph 3Bi(MeOx)X (MeOx = 2-methyl-8-quinolinolato; X = Cl, Br), PhBi(MeOx) 2 and PhBiOx 2 (Ox = 8-quinolinolato) have been prepared and characterized by electronic, IR and 1H NMR spectra. The crystal structure of Ph 3Bi(MeOx)Cl was determined by single-crystal X-ray diffraction from diffractometer data. Crystal data: C 28H 23NOClBi, monoclinic, space group P2 1/ n, a 17.05(1), b 13.89(1), c 10.51(1) Å, β 97.30(3)°, V 2468 Å 3, Z = 4, D calcd 1.70 g cm −3; R = 0.078, 3048 observed reflections. The complex is monomeric, and the molecules are well separated, with the metal atom in a distorted octahedral coordination environment. The metal atom makes with the bidentate ligand a BiO bond of 2.19(2) Å and a relatively weak BiN bond of 2.71(2) Å.

Liquid—liquid extraction of germanium with oxine derivatives

A rapid survey of the behaviour of ten extractants shows that oxine derivatives are amongst the most efficient reagents for liquid—liquid extraction of germanium (IV). A commercially available oxine derivative, Kelex 100 (HL) has been chosen. The extraction, when performed in acidic media, has acceptable kinetics ( t < 2 min for 50% extraction) and can be selective towards many metal ions (Zn 2+, Cd 2+, etc). It is also shown that the stripping can be achieved by contacting the organic phase with an aqueous solution containing a strong base e.g. sodium hydroxide. The extracted species have been identified as [GeL 2(OH) 2] and [GeL 3 + HSO 4 −] depending upon the acidity of the aqueous phase.

Spectrophotometric determination of zinc(II) and cadmiun(II) with methylthymol blue, oxine derivatives and cetylpyridinium chloride

Zinc(II) or cadmium(II) rapidly forms a mixed complex with methylthymol blue(MTB), cetylpyridinium chloride(CPC) and 5-nitroso-8-quinolinol (NO-oxine) {for zinc(II)} or 2-methyl-8-oxine (CH3-oxine) {for cadmium(II)} in a weak basic medium. The absorbance of the cadmium(II) complex at 630 nm (λmax) and that of the zinc(II) complex at 620 nm (λmax) were constant over the pH range from 7.6 to 9.0 for 3 h. The molar ratio of metal, MTB, oxine derivative and CPC in the mixed complex was a 1:1:1:2 by Job's method and the molar ratio method. The calibration curves were linear up to 4.0 μg/ml of cadmium(II) and 3.0 μg /ml of zinc (II). Sandell's sensitivity was 0.005 μg/cm2 for cadmium(II) and 0.003 p.g/cm2 for zinc(II). The recommended procedure is as follows: To a sample solution containing≤40 μg of cadmium(II) {or <30 μg of zinc(II)}, 0.5 ml of 1.0 × 10-2 M CPC, 0.25 ml of 1.0 × 10-2 M NO-oxine (or CH3-oxine solution), 2.0 ml of a borate buffer (pH 8.2) and 1.0 ml of 1.0 × 10-3 M MTB were added. The mixture was diluted to 10.0 ml with water. After the solution was kept at (2025)°C for 5 min, the absorbance was measured at 630 nm {for cadmium(II)} or at 620 nm {for zinc(II)} against a reagent blank. Nickel(II), cyanide, sulfide and thiocyanate interfered. Aluminum (III) and thorium (IV) could be masked with sodium fluoride, and mercury(II) with 1-ascorbic acid.

Some typical behaviours of the β-dodecenyl 8-hydroxyquinoline through its reactions with germanium(IV)

In order to enlarge the field of application of the 8-hydroxyquinoline, various derivatives have been proposed. Among them, the β-dodecenyl 8-hydroxyquinoline (βoxH) recently introduced looks very attractive although its behaviours are little known. In the present paper, the reactions between this reagent dissolved in kerosene and an aqueous solution of germanium(IV) have been chemically investigated. It has been shown that germanium(IV) is extracted into the organic phase by formation of two species, Ge(βox) 2(OH) 2 and Ge( βox) 3 +, HSO 4 −, whose proportions depend on the acidity of the aqueous phase. Their formation constants have been evaluated and a mathematical model based on the existence of these two species has been found satisfying. The results also show a main difference between the β-dodecenyl 8-hydroxyquinoline and oxine (or oxine derivatives such as methyl or chloride) since this latter gives only one complex, GeL 2(OH) 2. Such divergent comportments are thought to be due to the fact that βoxH is apparent much less alkaline than oxine.

The acidity of nitro and nitroso derivatives of oxine and the stability of their complexes with cobalt, nickel and copper

The acidity of nitro and nitroso derivatives of oxine and the stability of their complexes with cobalt, nickel and copper

Stability of metal oxinates — II Effect of the solvent composition

The protonation constants and the stability of metal complexes of several 5-substituted derivatives of oxine have been measured in 40, 60, and 75% vol/vol dioxane. The change in metal-complex stability with increasing dioxane content follows in large measure the stability change in the OH proton complexes, and is opposite to the change in stability of the (NH) + complexes. It appears that the effect of solvent composition on metal-complex stability yields only gross information on the relative importance of the OM and NM bonds in bidentate complexes of the type studied. Some data on SH and SM complexes is also presented.

A color reaction of thioxolone with iodine solution

A new method for the identification of thioxolone (4-hydroxy-2H-1, 3-benzoxathio1-2-one), used as antiseborrheic agent, based on the formation of its inclusion compound with iodine has been proposed.Thioxolone and its chlorinated derivatives on filter paper or thin layer plate of silica gel give a blue color, which is similar to that of iodine-starch, with spraying of 0.05 N iodine solution. Oxine and 2-methyloxine indicates same color reaction, although for many other phenolic compounds, such as phenol, resorcinol, salicylic acid, pentachlorophenol etc., and halogenated oxine derivatives, no remarkable color reaction is observed. Because the blue color does not appear in the solution, application of this reagent is limited. As shown in table I, the proposed reaction has not always high sensitivity, but is excellent in selectivity. As an example of application, this has been applied to the thin layer chromatography of alkaline decomposition products of thioxolone.