8-Hydroxyquinoline complexes

Atomic absorption spectrometry coupled with solvent extraction of iron complexes has been used to determine down to 0.5 pg/1 iron in seawater [354, 355]. Hiire [354] extracted iron as its 8-hydroxyquinoline complex. The sample is buffered to pH 3-6 and extracted with a 0.1 % methyl isobutyl ketone solution of 8-hydroxyquinoline. The extraction is aspirated into an air-acetylene flame and evaluated at 248.3 nm. 

Indium, cadmium and silver can be extracted into chloroform as their 8-hydroxyquinoline complexes, and the pH1/2 values for these metals are 2.1, 6.3 and 8.8 respectively. Plot a graph of theoretical percent extraction against pH over the range 0 to 9 for each metal. Deduce the pH of incipient extraction (0.01%) and complete extraction (99.99%) for each metal, and comment on the feasibility of separating each from the other assuming that all the distribution coefficients are sufficiently high. 

V.A. Montes, C. Li, R. Pohl, J. Shinar, and P. Anzenbacher Jr., Effective color tuning in organic light-emitting diodes based on Aluminium tris(5-aryl-8-hydroxyquinoline) complexes, Adv. Mater., 16 2001-2003 (2004). 

Colorimetric Determination of Vitamin C Using Fe(II)-5-Chloro-7-Iodo-8-Hydroxyquinoline Complex... 

The only other recorded compound for the +3 oxidation state is the 8-hydroxyquinoline complex, Pu(C9H6NO)3, precipitated when an aqueous solution containing plutonium(III) is added dropwise, in a stream of nitrogen, to an aqueous solution of the ligand in the presence of reducing agents. It is rapidly oxidized in air. 

Compounds of composition AmL3, where HL is 8-hydroxyquinoline, 5-chloro- or 5,7-dichloro-8-hydroxyquinoline, are precipitated when an aqueous solution containing americium(III) is added to an aqueous, or aqueous dioxane, solution of the ligand in the pH range 5.1-6.5.409 There is solvent extraction evidence for the californium(III) 5,7-dichloro-8-hydroxyquinoline complex.410... 

Why is it difficult to extract the EDTA complex of aluminum into an oiganic solvent but easy to extract the 8-hydroxyquinoline complex ... 

A mixture of the 8-hydroxyquinoline complexes of A1 and Mg weighed 1.084 3 g. When ignited in a furnace open to the air, the mixture decomposed, leaving a residue of ALO, and MgO weighing 0.134 4 g. Find the weight percent of Al(CyH6NO)3 in the original mixture. 

In-labeled white blood cells (WBC) have also been clinically used for infection and inflammation imaging. The neutral, lipid-soluble "In(oxine)3 (oxine = 8-hydroxyquinoline) complex penetrates cellular membranes and is used to label WBC. After diffusing intracellularly, the "In(oxine)3 complex dissociates and the " In is bound to nuclear and cytoplasmic proteins. Labeling of WBCs is done in plasma to avoid transchelation with transferrin in blood. The procedure consists of withdrawal of blood from patient, separation of red blood cells from white blood cells, purification of leucocytes, radiolabeling, followed by reinjection of the radiolabeled cells into the patient. The WBCs migrate to inflamed area and can lead to positive imaging. 

Before these findings, Van Deun et al. had investigated the luminescence properties of Er tris-8-hydroxyquinolinate complexes in dmso upon ligand excitation around 400 nm (Van Deun et al., 2003a). Since dmso molecules coordinate to the Er ion expelling the water molecules from the first coordination sphere, the most efficient quencher in such complexes is the aromatic C-H stretching vibration, which is located at 3060 cm . As a consequence, the second overtone almost matches the energy of the Er(" Ii3/2 " 115/2) transition ( 6500 cm ). 

A third technique which is somewhat less popular but still useful is application of surface adsorption reagents. Activated car n is generally used as the carrier after conversion of the metal ion(s) of interest to a suitable form. For example, iodide in ground water has been determined by this method after conversion to silver iodide [61]. Neutral 8-hydroxyquinoline complexes have been employed in which, again, the oxine complex is collected on activated carbon [62]. Use of activated carbon is particularly useful where PIXE is being employed as the analysis technique, since the resultant sample is ideal for direct presentation to the instrument [63]. Other preconcentration methods that have been employed in this area include electrodeposition [64], precipitation chromatography [65], liquid/liquid extraction, immobilized reagents [66], plus a variety of other techniques well known to the analytical chemist. 

The lUPAC (International Union for Pure and Applied Chemistry) reference method for the determination of nickel in serum and urine [43], for example, recommends an acid digestion followed by extraction with APDC-MIBK prior to ETAAS determination. Similar procedures were described for molybdenum in blood plasma which was extracted as the 8-hydroxyquinoline complex prior to its determination by ETAAS [44] and for vanadium in serum and urine [45]. There is no question, however, that these procedures require skilled operators. As multistage manual procedures they also bear the risk of analyte loss and/or contamination, so that the final result may not always reflect the analyte concentration in the original sample. 

Xu, X. Zhou, N. Xie, G. Syndiotactic polymerization of styrene using titanium-8-hydroxyquinolinate complexes/methylaluminoxane systems. Gaofenzi Xuebao 1997, 6, 746-748 Chem. Abstr. 1998,... 

The field of development of sensitizers for NIR-emitting lanthanide ions is currently booming. A large number of examples can be found in the literature, such as /3-diketone, ligands based on 8-hydroxyquinolinate, complexes with transition metal ions, MOFs, macrocyclic ligands, and so on. 

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