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 A study of the formation constants of ternary and quaternary complexes of some bivalent transition metals

2010 ◽  
Vol 75 (1) ◽  
pp. 75-82 ◽  
Author(s):  
Sangita Sharma ◽  
Dipika Dalwadi ◽  
Madhurjya Neog
Keyword(s):  
Salicylic Acid ◽  
Ionic Strength ◽  
Transition Metals ◽  
Metal Ions ◽  
Aqueous Medium ◽  
Coordination Number ◽  
Metal Ion ◽  
Formation Constants ◽  
Bivalent Transition Metals ◽  
The Stability

The formation of hetero-ligand 1:1:1, M(II)-Opda-Sal/Gly ternary and 1:1:1:1, M(II)-Opda-Sal-Gly quaternary complexes, where M(II) = Ni, Cu, Zn and Cd; Opda = o-phenylenediamine, Sal = salicylic acid, Gly = glycine, was studied pH-metrically in aqueous medium. The formation constants for the resulting ternary and quaternary complexes were evaluated at a constant ionic strength, ? = 0.20 mol dm-3 and temperature, 30?0.1 ?C. The order of the formation constants in terms of the metal ion for both type of complexes was found to be Cu(II) > Ni(II) > Zn(II) > Cd(II). This order was explained based on the increasing number of fused rings, the coordination number of the metal ions, the Irving - William order and the stability of various species. The expected species formed in solution were pruned with the Fortran IV program SPEPLOT and the stability of the ternary and quaternary complexes is explained.

scholarly journals Stability Constants of Some Biologically Important Pyrazoles and Their Ni2+Complexes in Different Dielectric Constant of Medium

2012 ◽  
Vol 9 (2) ◽  
pp. 637-641 ◽  
Author(s):  
S. D. Deosarkar ◽  
A. L. Puyad ◽  
S. A. Chavan
Keyword(s):  
Dielectric Constant ◽  
Ionic Strength ◽  
Stability Constants ◽  
Metal Ion ◽  
Formation Constants ◽  
Water Mixture ◽  
Electrostatic Forces ◽  
Ph Titration ◽  
Titration Technique

The proton-ligand stability constants of some biologically important new pyrazoles and formation constants of their complexes with Ni(II) were determined at 0.1 mol dm-3ionic strength and at 303.15 K in different dielectric constant of dioxane-water mixture by potentiometric method. The Calvin-Bjerrum's pH-titration technique as used by Irving and Rossotti was used for determination of stability constants. The results enabled to study the electrostatic forces of attraction between metal ion and ligand with changes in dielectric constant of the medium.

scholarly journals Interaction of Ampicillin and Amoxicillin with Mn2+: A Speciation Study in Aqueous Solution

Molecules ◽  
2020 ◽  
Vol 25 (14) ◽  
pp. 3110
Author(s):  
Claudia Foti ◽  
Ottavia Giuffrè
Keyword(s):  
Aqueous Solution ◽  
Stability Constants ◽  
Metal Ion ◽  
Formation Constants ◽  
Enthalpy Change ◽  
Ligand Concentration ◽  
Empirical Parameter ◽  
Speciation Study ◽  
Potentiometric Measurements ◽  
The Stability

A potentiometric and UV spectrophotometric investigation on Mn2+-ampicillin and Mn2+-amoxicillin systems in NaCl aqueous solution is reported. The potentiometric measurements were carried out under different conditions of temperature (15 ≤ t/°C ≤ 37). The obtained speciation pattern includes two species for both the investigated systems. More in detail, for system containing ampicillin MLH and ML species, for that containing amoxicillin, MLH2 and MLH ones. The spectrophotometric findings have fully confirmed the results obtained by potentiometry for both the systems, in terms of speciation models as well as the stability constants of the formed species. Enthalpy change values were calculated via the dependence of formation constants of the species on temperature. The sequestering ability of ampicillin and amoxicillin towards Mn2+ was also evaluated under different conditions of pH and temperature via pL0.5 empirical parameter (i.e., cologarithm of the ligand concentration required to sequester 50% of the metal ion present in traces).

scholarly journals Stability Constants of Lanthanide Metal Ions Chelates with Substituted Pyrazoles in Different Solvents

2011 ◽  
Vol 8 (1) ◽  
pp. 131-136 ◽  
Author(s):  
G. H. Murhekar ◽  
A. R. Raut ◽  
R. S. Sonone
Keyword(s):  
Ionic Strength ◽  
Metal Ions ◽  
Stability Constants ◽  
Water Mixture ◽  
Solvent Medium ◽  
Acetone Water ◽  
Lanthanide Metal ◽  
Substituted Pyrazoles ◽  
Metal Ligand

The reaction of Pr (III) and Nd (III) metal ions with some substituted pyrazoles, at 0.1M ionic strength and at 30 ± 0.10C in 70% acetone-water mixture and 70% propanol-water mixture have been studied pH-metrically. The data obtained were used to estimate the values of proton-ligand (pK) and metal-ligand (logK) stability constants in different solvents. It is observed that the pK and logK values in 70% propanol-water mixture are grater than in 70% acetone -water mixture. Pr (III) and Nd (III) metal ions formed 1:1 and 1:2 complexes with all the ligands in both solvent medium.

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.

Complexation of Europium(III) with Carbonate Ions in Groundwater

1988 ◽  
Vol 127 ◽  
Author(s):  
A. Chatt ◽  
R. R. Rao
Keyword(s):  
Ionic Strength ◽  
Metal Ion ◽  
Ion Pairing ◽  
Formation Constants ◽  
Trioctylphosphine Oxide ◽  
Synergic Effect ◽  
Extraction Behavior ◽  
Carbonate Ions ◽  
Synergic Extraction ◽  
Carbonate Complexation

ABSTRACTThe equilibrium extraction behavior of Eu(III) studied in chloroform solutions containing l-nitroso-2-naphthol (HA), either alone or combined with 2, 2'-dipyridyl, 1, 10-phenanthroline (phen), or trioctylphosphine oxide (TOPO) shows that the metal ion is extracted as either EuA, EuA3.2, 2'-dipyridyl, EuA3·phen, or EuA3·2TOPO, respectively. The synergic effect of phen or TOPO on the extraction of Eu(III) with l-nitroso-2-naphthol is more pronounced over that of 2, 2'-dipyridyl. The carbonate complexation of Eu(III) has been studied in 1.0 M ionic strength solutions at pH 8.0–9.0 and 25 °C using the synergic extraction system of 1-nitrşso-2-naphthol and pheo. The following complexes have been identified: EuCO34, Eu(CO3)2-, Eu(CO3)33-, and Eu(CO3)45- the results suggest that the first two species predominate at carbonate concentrations and pH similar to those found in most groundwaters. The formation constants of these species have been calculated at zero ionic strength using both SIT and ion pairing models.

scholarly journals Study of Complex Formation Between Iodoquinol (IQ) and Co2+, Mn2+, Cd2+, Pb2+and Zn2+Cations in Binary Aqueous / Non-aqueous Solvent Using Spectrophotometry

2007 ◽  
Vol 4 (4) ◽  
pp. 581-586 ◽  
Author(s):  
A. Nezhadali ◽  
H. A. Hosseini ◽  
P. Langara
Keyword(s):  
Ionic Strength ◽  
Complex Formation ◽  
Stability Constants ◽  
Spectrophotometric Method ◽  
Formation Constants ◽  
The Other ◽  
Aqueous Solvent ◽  
The Stability ◽  
Complexation Reactions

The complexation reactions between iodoquinol and Co2+, Mn2+, Cd2+, Pb2+and Zn2+cations were studied in different DMF/H2O binary mixtures at the ionic strength of 0.1(using NaNO3).The spectrophotometric method was used for the determination of formation constants and the stoichiometries. The stoichiometry of the complexes is established 1:1 by Job's and mole ratio methods. It was found that the stability constants of the complex formed between the ligand (IQ) and the cations in the all cases increase with increasing of the non-aqueous solvent. In the most cases the maximum formation constants between Zn2+ion and IQ were obtained respect to the other cations.

Chélates du fer (III) avec des anions dicarboxylates

1968 ◽  
Vol 46 (8) ◽  
pp. 1383-1388 ◽  
Author(s):  
M. Deneux ◽  
R. Meilleur ◽  
R. L. Benoit
Keyword(s):  
Ionic Strength ◽  
Complex Formation ◽  
Dicarboxylic Acids ◽  
Formation Constants ◽  
Acidity Constants ◽  
Spectrophotometric Methods ◽  
Stability Order ◽  
The Stability

Complex formation between iron(III) and oxalate, malonate, succinate, glutarate, and acetate ions has been studied by potentiométric and spectrophotométric methods at 25 °C, ionic strength 0.52 ± 0.02, and [Formula: see text] and 0.1 M H+ concentrations. The acidity constants of the dicarboxylic acids and the formation constants of the monochelates of iron(III) have been determined. The stability order is as follows: [Formula: see text].

Studies on the Mixed Ligand Complexes Involving Ligands of Biological Importance (Ni(II)/Zn(II)/Cd(II)-1,10-phenanthroline-2,2′ -bipyridyl-phenylalanine)

1977 ◽  
Vol 32 (4) ◽  
pp. 426-429 ◽  
Author(s):  
G. S. Malik ◽  
S. P. Singh ◽  
J. P. Tandon
Keyword(s):  
Ionic Strength ◽  
Metal Ion ◽  
Formation Constants ◽  
Ternary Complexes ◽  
Mixed Ligand ◽  
Mixed Ligand Complexes ◽  
Biological Importance

pH-metric studies on the interaction of Ni(II), Zn(II) or Cd(II) with 1,10-phenanthroline (Phen) or 2,2′-bipyridyl (Bipy) in the presence of phenylalanine (Phe) indicate the formation of 1:1:1 mixed ligand chelates and their monohydroxo derivatives. The addition of Phe takes place after the combination of Phen or Bipy with the metal ion is complete. The formation constants of the resulting complexes have been determined at 30 ± 1 °C and ionic strength (µ) = 0.1 KNO3 and the ternary complexes involving Phen are found to be more stable than the corresponding complexes involving Bipy as primary ligand.

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