Differential Thermal Analysis of Some Metal Chelates of 8-Quinolinol and Substituted 8-Quinolinols.

Wendlandt, W.W.; Horton, G.R.

doi:10.1021/ac60189a021

Cited by 31 publications

(6 citation statements)

References 13 publications

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“…The final process with a maximum at 445-460 o C corresponds to ignition of the residual organic ligand yielding ThO 2 with the intermediate formation ThOCO 3 (23) . In general, from peak maxima temperatures, Th (IV) complexes are less thermally stable than those of UO 2 (II) and this agrees with the previous work (25) .…”

Section: Complexes In the Solid Statesupporting

confidence: 92%

Studies of Uranyl (UO2)+2 and Thorium (Th)4+ Complexes with some Azo-β-diketone in Methanol- water Solvent

2012

Egypt. J. Chem.

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HE THERMODYNAMIC parameter of complexes of UO 2 (II)and ……Th(IV) cations with ortho substituted of some phenyl hydrazo compounds of di-bnzoyl methane or acetoacetanilide was studied. The ortho-substitution involves carboxy or phenolic or thiol groups. The potentiometric titrations were carried out in 75% (v/v) methanol-water and 0.10 M KNO 3. The thermodynamic parameters have been divided into electrostatic (el.) and non-electrostatic (non), which give some light upon the nature of the coordination between metal ions and ligands. Comparison of the experimental and calculated (using modified Born equation) values of ΔG indicates the inner sphere nature of all the complex systems. Spectrophotometric studies were carried out between UO 2 (II) and o-hydroxy phenyl hydrazo acetoacetanilide. Also, conduct metric titration for both UO 2 (II) and Th(IV) with o-carboxy phenyl-hdrazo acetoacetanilide to confirm the stoichiometric structures of formed complexes was calculated. The solid complexes were isolated and characterized by elemental analysis, infrared and TG, DTG and DTA measurements. The results show that the ligands behave towards the metal ion as dibasic tridentate ligands.

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Section: Complexes In the Solid Statesupporting

confidence: 92%

Studies of Uranyl (UO2)+2 and Thorium (Th)4+ Complexes with some Azo-β-diketone in Methanol- water Solvent

2012

Egypt. J. Chem.

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“…The former complex is presumably octahedral, but the structure of Mn(oxine) 2 is not known although it has been considered to be square planar 576 . The thermal dissociations of the complexes have been investigated 577 . In addition to Mn(oxine) 2 an adduct Mn(oxine) 2 -2oxine-H has also been described which is possibly 8-coordinate 578 .…”

Section: Bidentate (O-n) Donorsmentioning

confidence: 99%

Manganese

Kemmitt¹

1973

The Chemistry of Manganese, Technetium and Rhenium

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“…First prepared by Skraup, Bedall, and Fischer in the early 1870s, 8-hydroxyquinoline (8HQ) and its derivatives comprise a family of lipophilic metal ion chelators that have been used in a range of applications from laboratory-based techniques to medications over the last century. For example, 8HQs have been used extensively since the 1920s as gravimetric and colorimetric analytical reagents for transition metals. − 8-Hydroxyquinoline (oxine; 8HQ), as well as many of its derivatives (Figure ), including dihalogenated 5,7-dibromo-8-hydroxiquinoline (bromoxine; B2Q), 5,7-dichloro-8-hydroxiquinoline (chloroxine; Cl2Q), and 5,7-diiodo-8-hydroxiquinoline (iodoxine; I2Q), have been used for this purpose.…”

Section: Introductionmentioning

confidence: 99%

Solution Chemistry of Copper(II) Binding to Substituted 8-Hydroxyquinolines

et al. 2020

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8-Hydroxyquinolines (8HQs) are a family of lipophilic metal ion chelators that have been used in a range of analytical and pharmaceutical applications over the last 100 years. More recently, CQ (clioquinol; 5-chloro-7-iodo-8-hydroxyquinoline) and PBT2 (5,7-dichloro-2-[(dimethylamino)methyl]-8-hydroxyquinoline) have undergone clinical trials for the treatment of Alzheimer's disease and Huntington's disease. Because CQ and PBT2 appear to redistribute metals into cells, these compounds have been redefined as copper and zinc ionophores. Despite the attention surrounding the clinical trials and the clear link between 8HQs and metals, the fundamental solution chemistry of how these compounds bind divalent metals such as copper and zinc, as well as their mechanism(s) of action in mammalian systems, remains poorly understood. In this study, we used a combination of X-ray absorption spectroscopy (XAS), high-energy resolution fluorescence detected (HERFD) XAS, electron paramagnetic resonance (EPR), and UV−visible absorption spectroscopies to investigate the aqueous solution chemistry of a range of 8HQ derivatives. To circumvent the known solubility issues with 8HQ compounds and their complexes with Cu(II), and to avoid the use of abiological organic solvents, we have devised a surfactant buffer system to investigate these Cu(II) complexes in aqueous solution. Our study comprises the first comprehensive investigation of the Cu(II) complexes formed with many 8HQs of interest in aqueous solution, and it provides the first structural information on some of these complexes. We find that halogen substitutions in 8HQ derivatives appear to have little effect on the Cu(II) coordination environment; 5,7-dihalogenated 8HQ conformers all have a pseudo square planar Cu(II) bound by two quinolin-8-olate anions, in agreement with previous studies. Conversely, substituents in the 2-position of the 8HQ moiety appear to cause significant distortions from the typical square-planar-like coordination of most Cu(II)-bis-8HQ complexes, such that the 8HQ moieties in the Cu(II)-bis-8HQ complex are rotated approximately 30−40°apart in a "propeller-like" arrangement.

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Differential Thermal Analysis of Some Metal Chelates of 8-Quinolinol and Substituted 8-Quinolinols.

Cited by 31 publications

References 13 publications

Studies of Uranyl (UO2)+2 and Thorium (Th)4+ Complexes with some Azo-β-diketone in Methanol- water Solvent

Studies of Uranyl (UO2)+2 and Thorium (Th)4+ Complexes with some Azo-β-diketone in Methanol- water Solvent

Manganese

Solution Chemistry of Copper(II) Binding to Substituted 8-Hydroxyquinolines

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