TARTRATE COMPLEXES OF THE RARE-EARTH ELEMENTS II. THE dl- AND meso-TARTRATE COMPLEXES OF La, Ce, Pm, Tm, AND Y

1963 ◽  
Vol 41 (10) ◽  
pp. 2566-2574 ◽  
Author(s):  
P. G. Manning
Keyword(s):  
Rare Earth ◽  
Ionic Strength ◽  
Stability Constant ◽  
Metal Ion ◽  
Ionic Radius ◽  
Ion Association ◽  
Liquid Distribution ◽  
Distribution Method ◽  
The Stability ◽  
Two Stages

The liquid-liquid distribution method has been used to measure the stability constants of the dl-tartrate complexes of La3+, Ce3+, Pm3+, Tm3+, and Y3+, and the meso-tartrate complexes of Ce3+ and Tm3+. Thenoyltrifluoroacetone was the organic phase extractant, and the aqueous phase, acetate buffered (pH = 4.53), was maintained at a constant ionic strength (0.0597) by means of sodium perchlorate.The order of stabilities for the two stages of ion association are[Formula: see text][Formula: see text]The b1/b2 values, where b is a stepwise stability constant defined as [Formula: see text]are lower (by factors of 4–8) for the dl-tartrates than for the meso-tartrate complexes. The b1/b2 ratios decrease as the ionic radius of the metal ion decreases, and for the dl-tartrates of Tb3+, Y3+, and Tm3+, the b1/b2 values are 5.3, 5.0, and 4.3 respectively. The enhanced stabilities of the 1:2 (ML2−) dl-tartrate chelates have been interpreted in terms of ligand–ligand hydrogen bridging in the 1:2 complex.

Europium tartronate and mandelate ion association in water

1967 ◽  
Vol 45 (14) ◽  
pp. 1643-1647 ◽  
Author(s):  
P. G. Manning
Keyword(s):  
Ionic Strength ◽  
Solvent Extraction ◽  
Stability Constant ◽  
Stability Constants ◽  
Ion Association ◽  
Tridentate Ligand ◽  
Radiotracer Method ◽  
The Stability ◽  
Two Stages ◽  
Low Ionic Strength

Stepwise stability constants have been determined for the 1:1 and 1:2 Eu3+:mandelate− and Eu3+:tartronate2− complexes in water. Measurements were made at low ionic strength and the temperature was 25 °C. The solvent-extraction–radiotracer method was used.For the mandelate system at an ionic strength of 0.104, K1 = 5.0 × 102, K2 = 1.58 × 102, and K1:K2 = 3.1. The K1:K2 ratios suggest monodentate ligandcy.The stepwise stability constants for the two stages of tartronate ion association are: K1 = 7.1 ( ± 15%) × 104 and K1K2 = 4.2 ( ± 5%) × 108. The magnitudes of the stability constants suggest that tartronate is a tridentate ligand. The stability constant ratios are discussed with reference to the ratios for piperidinedicarboxylate and iminodiacetate complexes.

scholarly journals Stability Constant of Rare Earth Metals with Substituted Thiazoles at 298.15K

2016 ◽  
Vol 64 ◽  
pp. 106-109
Author(s):  
A.B. Naik ◽  
M.S. Poharkar
Keyword(s):  
Rare Earth ◽  
Ionic Strength ◽  
Stability Constant ◽  
Rare Earth Metal ◽  
Rare Earth Metals ◽  
Sodium Perchlorate ◽  
Earth Metal ◽  
Water Mixture ◽  
Dissociation Process ◽  
The Stability

The stability constant on complexation of rare earth metal ions Eu (III), Gd (III), Nd (III) and Tb (III) with substituted thiazole in 70% Dioxane (Dx)-water mixture have been determined by a pH and spectrophotometric method at 298.15K and ionic strength 0.1mol.dm-3(sodium perchlorate). At constant temperature, the stability constant of the formed complexes decreases in the order Tb (III), Gd (III), Eu (III), Nd (III). The dissociation process is non-spontaneous, endothermic and entrophically unfavorable while formation of metal complexes has been found to be spontaneous, endothermic and entrophically favorable.

EUROPIUM OXALATE ION ASSOCIATION IN WATER

1966 ◽  
Vol 44 (24) ◽  
pp. 3057-3062 ◽  
Author(s):  
P. G. Manning
Keyword(s):  
Acetic Acid ◽  
Ionic Strength ◽  
Stability Constant ◽  
Stability Constants ◽  
Aqueous Phase ◽  
Sodium Acetate ◽  
Ion Association ◽  
Sodium Oxalate ◽  
Aqueous Sodium ◽  
Oxalate Ion

The partitioning of radiotracer 152/151Eu between aqueous sodium oxalate (Na2L) solutions and toluene solutions of thenoyltrifluoroacetone (HTTA) has been studied as a function of the oxalate concentration. The pH of the aqueous phase was controlled by means of sodium acetate – acetic acid mixtures and the ionic strength (I) by NaCl or NaClO4.At low ionic strengths (~0.05) and [L] ~10−4 M EuL+ formed, but at I = 0.95 and [L] ~10−3 M EuL2− also formed. Stability constants for the 1:1 and 1:2 (metal:ligand) complexes are reported.The magnitudes of the stepwise stability constant ratios are discussed.

Transferrin binding of Al3+ and Fe3+.

1987 ◽  
Vol 33 (3) ◽  
pp. 405-407 ◽  
Author(s):  
R B Martin ◽  
J Savory ◽  
S Brown ◽  
R L Bertholf ◽  
M R Wills
Keyword(s):  
Stability Constant ◽  
Blood Plasma ◽  
Stability Constants ◽  
Metal Ion ◽  
Equilibrium Dialysis ◽  
Ion Binding ◽  
Metal Ion Binding ◽  
Quantitative Studies ◽  
Intensity Changes ◽  
The Stability

Abstract An understanding of Al3+-induced diseases requires identification of the blood carrier of Al3+ to the tissues where Al3+ exerts a toxic action. Quantitative studies demonstrate that the protein transferrin (iron-free) is the strongest Al3+ binder in blood plasma. Under plasma conditions of pH 7.4 and [HCO3-]27 mmol/L, the successive stability constant values for Al3+ binding to transferrin are log K1 = 12.9 and log K2 = 12.3. When the concentration of total Al3+ in plasma is 1 mumol/L, the free Al3+ concentration permitted by transferrin is 10(-14.6) mol/L, less than that allowed by insoluble Al(OH)3, by Al(OH)2H2PO4, or by complexing with citrate. Thus transferrin is the ultimate carrier of Al3+ in the blood. We also used intensity changes produced by metal ion binding to determine the stability constants for Fe3+ binding to transferrin: log K1 = 22.7 and log K2 = 22.1. These constants agree closely with a revision of the reported values obtained by equilibrium dialysis. By comparison with Fe3+ binding, the Al3+ stability constants are weaker than expected; this suggests that the significantly smaller Al3+ ions cannot coordinate to all the transferrin donor atoms available to Fe3+.

scholarly journals Inhibition of enzymes by metal ion-chelating reagents. Theory and new graphical methods of study

1974 ◽  
Vol 137 (1) ◽  
pp. 55-60 ◽  
Author(s):  
William G. Bardsley ◽  
Robert E. Childs
Keyword(s):  
Stability Constant ◽  
Metal Ions ◽  
Metal Ion ◽  
Graphical Methods ◽  
Ligand Interaction ◽  
Mechanism Of Inhibition ◽  
The Stability ◽  
Chelating Reagents

1. The mechanism of inhibition of enzymes by metal ion-chelating reagents is discussed and equations derived. 2. Two distinct mechanisms are postulated and graphical methods are given for differentiating between them. 3. Where the metal ion is actually removed from the enzyme to form a co-ordination complex in solution, a procedure is described for obtaining the stability constant for metal–enzyme interaction, the number of metal ions involved and the stoicheiometry of metal ion–ligand interaction.

Preparation and Luminescent Properties of the La3+ Doped Tb3+-Hydroxyapatite

2014 ◽  
Vol 716-717 ◽  
pp. 32-35
Author(s):  
Wen Bin Liu ◽  
Adu ◽  
Yu Guang Lv ◽  
Li Li Yu ◽  
Yong Xiang Du ◽  
...  
Keyword(s):  
Rare Earth ◽  
Metal Ion ◽  
Chemical Properties ◽  
Earth Metal ◽  
Luminescent Properties ◽  
Central Metal ◽  
X Ray Diffraction ◽  
Light Emitting ◽  
Terbium Ion ◽  
The Stability

In this paper, a rare earth metal terbium ion as the central metal ion, a nanohydroxyapatite powder of the lanthanum doped terbium was synthesis by precipitation with hydroxyapatite as ligand. The sample was characterized by infrared spectrum, fluorescence spectrum and X ray diffraction instrument, and the thermal properties and fluorescence properties, structure of powderes were discussed. A nanohydroxyapatite powder of the lanthanum doped terbium achieves the maximum luminous intensity, when the La3+ doping concentration of Tb3+ was HAP 5% (La3+ and Tb3+ mole fraction ratio) devices. Rare earth powder of the lanthanum doped terbium hydroxyapatite has the stability chemical properties, the luminescence properties and good biological activity, the rare earth powder has good luminescent properties can be used in preparation of a good light emitting device. At the same time a nanohydroxyapatite powder of the lanthanum doped terbium has good antibacterial property, can be used as antibacterial materials.

scholarly journals Formation constants of lanthanide metal ion chelates with some substituted sulfonic acids

2010 ◽  
Vol 7 (1) ◽  
pp. 235-238
Author(s):  
R. S. Sonone ◽  
G. H. Murhekar
Keyword(s):  
Ionic Strength ◽  
Sulfonic Acid ◽  
Metal Ion ◽  
Formation Constants ◽  
Trifluoromethanesulfonic Acid ◽  
Water Mixture ◽  
Benzenesulfonic Acid ◽  
Sulfonic Acids ◽  
Lanthanide Metal ◽  
The Stability

The pKa and logK values of some substituted sulfonic acid in 70% (v/v) dioxane-water mixture have been determined using pH metric measurements. The stability constant of complexes of Gd (III), Tb (III) and Ho (III) with p-aminobenzenesulfonic (L1) and p-sulfophthalic acid (L2), 2-amino-5-chloro benzenesulfonic acid (L3) and trifluoromethanesulfonic acid (L4) have been determined at 0.1M ionic strength at 28±0.1 0C pH metrically. It is observed that both the metal ions formed 1:1 & 1:2 complexes with all the ligands.

scholarly journals Nano Synthesis and Characterization of Complex Derived from Silver Metal Conjugated with Midodrine Hydrochloride

2021 ◽  
Vol 37 (1) ◽  
pp. 157-161
Author(s):  
Namita Bharadwaj ◽  
Jaishri Kaushik
Keyword(s):  
Stability Constant ◽  
Silver Nanoparticle ◽  
Metal Ion ◽  
Ratio Method ◽  
Synthesis And Characterization ◽  
Face Centered Cubic ◽  
Uv Visible ◽  
Face Centered ◽  
The Stability

The stability constant Kf for the complexation of Ag(Ⅰ) metal ion with Midodrine hydrochloride were determinedby spectrophotometric method at room temperature .The colored complexes were measured at 300 nm. The stability constant of the complexes were found to be 5.47 by mole ratio method. The stoichiometry of the complexes formed between the Midodrine drug and Ag (Ⅰ) metal ion are 1:1 M/L ratio. Silver conjugated Midodrine hydrochloride Nano synthesized and characterized by UV/Visible spectroscopy, SEM, XRD and FT-IR. The UV/Visible spectra of Midodrine –Ag nanoparticle in the range of 322 nm. XRD conformThe crystallite size of Midodrine - Ag (Ⅰ) nanoparticles are found to be 64.5 nmfrom Debye Scherer formula.Thecrystallinity of nanoparticles is Face centered cubic structure. SEM conform of particle size and surface morphology, FTIR analyzed involvement of -NH2 group in Midodrine is the stabilized of silver nanoparticle. This research is focuses on complexation, Nano synthesis and characterization of Drug-silver nanoparticle for antihypotention therapy.

TARTRATE COMPLEXES OF THE RARE-EARTH ELEMENTS: I. THE d-, dl-, AND meso-TARTRATE COMPLEXES OF Tb AND Eu

1963 ◽  
Vol 41 (10) ◽  
pp. 2557-2565 ◽  
Author(s):  
P. G. Manning
Keyword(s):  
Rare Earth ◽  
Ionic Strength ◽  
Sodium Perchlorate ◽  
Ion Association ◽  
Complex Species ◽  
Sodium Tartrate ◽  
Aqueous Sodium ◽  
Coordination Numbers ◽  
Trace Concentrations ◽  
Radiotracer Techniques

Solvent extraction and radiotracer techniques have been applied to the study of metal – tartrate ion association in water at 25 °C. Trace concentrations of the radioisotopes Tb160 and Eu152/154 were equilibrated between aqueous sodium tartrate solutions and organic phases of thenoyltrifluoroacetone in toluene. The ionic strength (0.0597) and the pH (4.53) of the aqueous phase were kept constant by means of sodium perchlorate and sodium acetate.Metal complexing with the d-, dl-, and meso isomers of the ligand was examined. For all isomers two complex species were identified with metal:ligand ratios of 1:1 and 1:2, and stability constants for both stages of ion association have been estimated. No third (1:3) complex was detected.Metal coordination numbers and the formation of tartrate–tartrate hydrogen bridges in the 1:2 complex are discussed.

Chemical speciation in fresh, saline and hyper-saline waters

2014 ◽  
Vol 86 (7) ◽  
pp. 1097-1104 ◽  
Author(s):  
Stefka Tepavitcharova ◽  
Diana Rabadjieva ◽  
Tihomir Todorov ◽  
Antonina Kovacheva ◽  
Manos Dassenakis ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Natural Waters ◽  
Chemical Species ◽  
Interaction Model ◽  
Ion Association ◽  
Water Systems ◽  
Association Model ◽  
Combined Model ◽  
Inorganic Composition ◽  
The Stability

AbstractA thermodynamic model is proposed, which combines the ion association and the ion interaction models using the extended database pit2010.dat for a more precise modeling of the chemical species of micro components in natural waters of varying ionic strength (fresh, saline and hyper-saline). Compared to the ion association model, the proposed combined model more adequately describes the complex character of the ionic interactions. The performance of the combined ion association/ion interaction model compared to that of the ion association model is illustrated in case studies of several Bulgarian natural water systems of different ionic strength and type of pollution. The results are interpreted in terms of the chemical behavior of the metals and of their chemical species in the water systems, which is defined by the redox potential, pH, cationic and anionic organic and inorganic composition of the water systems and by the ability of the metals to preferentially coordinate with some anions, as well as by the stability of the corresponding species. The affinity of the transition metals towards the ligands is explained by the “hardness-softness” factor and the crystal field stabilization energy (CFSE).

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