scholarly journals Complexation of molybdenum(VI) with methyliminodiacetic acid in different water + methanol solutions

2016 ◽  
Vol 81 (5) ◽  
pp. 541-551
Author(s):  
Saleh Zeighaminezhad ◽  
Kavosh Majlesi
Keyword(s):  
Sodium Chloride ◽  
Aqueous Solutions ◽  
Stability Constants ◽  
Specific Interactions ◽  
Microsoft Excel ◽  
Methanol Solutions ◽  
The Stability ◽  
Methyliminodiacetic Acid

The complexation of molybdenum(VI) with methyliminodiacetic acid (MIDA) at pH = 6.00, T = 298 K , I = 0.1 mol.dm-3 of sodium chloride and different water + methanol solutions (0-45% v/v) was studied by using potentiometric and UV spectrophotometric measurements. The stability constants values were calculated and their trends have been interpreted by using the Kamlet-Abboud-Taft (KAT) model in order to investigate the role of different specific and non-specific interactions in the aqueous solutions of methanol. Hyperquad 2013 and Microsoft Excel 2010 softwares have been used for the calculations.

On the Structure of Lead(II) Complexes in Aqueous Solutions. I. Trinuclear Clusters

1995 ◽  
Vol 60 (4) ◽  
pp. 527-536 ◽  
Author(s):  
Martin Breza ◽  
Alena Manová
Keyword(s):  
Quantum Chemistry ◽  
Aqueous Solutions ◽  
Electronic Structures ◽  
Mndo Method ◽  
Model Systems ◽  
Trinuclear Clusters ◽  
The Stability ◽  
Semiempirical Mndo

Using semiempirical MNDO method of quantum chemistry the optimal geometries and corresponding electronic structures of [Pb3(OH)n]6-n model systems as well as of their hydrated [Pb3(OH)n(H2O)8-n]6-n analogues (n = 4, 5) are investigated. The most stable trinuclear lead(II) complexes present in aqueous solutions correspond to cyclo-(μ3-OH)(μ2-OH)3Pb32+, Pb(μ-OH)2Pb(μ-OH)2Pb2+, cyclo-(μ3-OH)2(μ2-OH)3Pb3+, Pb(OH)(μ-OH)2Pb(μ-OH)Pb(OH)+ and Pb(OH)(μ-OH)2Pb(μ-OH)2Pb+ systems. The key role of OH bridges (by vanishing direct Pb-Pb bonds) on the stability of individual isomers is discussed.

The affinity of aldehydic compounds to complex formation. Nickel(II) and cobalt(II) complexes with 2-pyridinecarboxaldehyde

1977 ◽  
Vol 55 (14) ◽  
pp. 2613-2619 ◽  
Author(s):  
M. S. El-Ezaby ◽  
M. A. El-Dessouky ◽  
N. M. Shuaib
Keyword(s):  
Complex Formation ◽  
Aqueous Solutions ◽  
Stability Constants ◽  
Metal Ion ◽  
Experimental Conditions ◽  
Complex Species ◽  
Spectrophotometric Methods ◽  
Complex Equilibria ◽  
The Stability ◽  
Hydroxy Groups

The interactions of Ni(II) and Co(II) with 2-pyridinecarboxaldehyde have been investigated in aqueous solutions at μ = 0.10 M (KNO3) at 30 °C. The stability constants of different complex equilibria have been determined using potentiometric methods. Spectrophotometric methods were also used in the case of the nickel(II) – 2-pyridinecarboxaldehyde system. It was concluded that nickel(II) and cobalt(II), analogous to copper(II), enhance hyrdation of 2-pyridinecarboxaldehyde prior to deprotonation of one of the geminal hydroxy groups. Complex species of 1:1 as well as 1:2 metal ion to ligand composition exist under the experimental conditions used.

Determination of the stability constants for equilibriums involving copper(II) and fluoride ions in aqueous solutions

1974 ◽  
Vol 13 (6) ◽  
pp. 1434-1437 ◽  
Author(s):  
Sidney. Gifford ◽  
Wayne. Cherry ◽  
Joe. Jecmen ◽  
Mike. Readnour
Keyword(s):  
Aqueous Solutions ◽  
Stability Constants ◽  
Fluoride Ions ◽  
The Stability

Single and double crown macrocyclic derivatives of cyclotriphosphazene as receptors of silver(i) ions

RSC Advances ◽  
2015 ◽  
Vol 5 (48) ◽  
pp. 38435-38442 ◽  
Author(s):  
Natalia Gutowska ◽  
Piotr Seliger ◽  
Grzegorz Andrijewski ◽  
Mariola Siwy ◽  
Magdalena Małecka ◽  
...  
Keyword(s):  
Stability Constants ◽  
Lariat Ethers ◽  
Double Crown ◽  
Methanol Solutions ◽  
The Stability ◽  
Derivatives Of

Two new single and double P-pivot lariat ethers have been synthesized and the stability constants of their complexes with silver(i) ions were determined in acetonitrile and methanol solutions.

The role of divalent cations in the activation of the NADP+-specific isocitrate dehydrogenase from Pisum sativum L.

1977 ◽  
Vol 55 (9) ◽  
pp. 928-934 ◽  
Author(s):  
Robert J. Maloney ◽  
David T. Dennis
Keyword(s):  
Ionic Strength ◽  
Stability Constants ◽  
Isocitrate Dehydrogenase ◽  
Divalent Cations ◽  
Free Form ◽  
Saturation Kinetics ◽  
The Difference ◽  
The Stability ◽  
Kinetics Of

A divalent cation electrode was used to measure the stability constants (association constants) for the magnesium and manganese complexes of the substrates for the NADP+-specific isocitrate dehydrogenase (EC 1.1.1.42) from pea stems. At an ionic strength of 26.5 mM and at pH 7.4 the stability constants for the Mg2+–isocitrate and Mg2+–NADP+ complexes were 0.85 ± 0.2 and 0.43 ± 0.04 mM−1 respectively and for the Mn2+–isocitrate and Mn2+–NADP+ complexes they were 1.25 ± 0.07 and 0.75 ± 0.09 mM−1 respectively. At the same ionic strength but at pH 6.0 the Mg2+–NADPH and Mn2+–NADPH complexes had stability constants of 0.95 ± 0.23 and 1.79 ± 0.34 mM−1 respectively. Oxalosuccinate and α-ketoglutarate do not form measureable complexes under these conditions. Saturation kinetics of the enzyme with respect to isocitrate and metal ions are consistent with the metal–isocitrate complex being the substrate for the enzyme. NADP+ binds to the enzyme in the free form. Saturation kinetics of NADPH and Mn2+ indicate that the metal–NADPH complex is the substrate in the reverse reaction. In contrast the pig heart enzyme appears to bind free NADPH and Mn2+. A scheme for the reaction mechanism is presented and the difference between the reversibility of the NAD+ and NADP+ enzyme is discussed in relation to the stability of the NADH and NADPH metal complexes.

Thermodynamic study of the complexation between Nd3+ and functionalized diacetamide ligands in solution

2016 ◽  
Vol 45 (30) ◽  
pp. 11968-11975 ◽  
Author(s):  
Phuong V. Dau ◽  
Zhicheng Zhang ◽  
Phuong D. Dau ◽  
John K. Gibson ◽  
Linfeng Rao
Keyword(s):  
Aqueous Solutions ◽  
Stability Constants ◽  
Thermodynamic Study ◽  
Amine Functionalized ◽  
The Stability ◽  
Diamide Ligands

Three amine-functionalized diamide ligands form tridentate complexes with Nd3+ in aqueous solutions. The stability constants of the complexes follow the order of the ligand basicity that can be tuned by different substitutional groups.

scholarly journals STABILITY CONSTANTS OF L-ASPARAGINE AND L-LEUCINE COMPLEXES WITH SOME LANTHANIDE IN AQUEOUS SOLUTIONS AT 298.15 K

2017 ◽  
Vol 61 (1) ◽  
pp. 37
Author(s):  
Alexandr I. Lytkin ◽  
Natalya V. Chernyavskaya ◽  
Darya K. Smirnova
Keyword(s):  
Amino Acids ◽  
Aqueous Solutions ◽  
Stability Constants ◽  
Quantitative Estimation ◽  
A Priori ◽  
Complex Compounds ◽  
Complexing Agent ◽  
Stability Of Complexes ◽  
Biological Substrates ◽  
The Stability

Lanthanides have a high affinity toward ligands containing donor oxygen atoms, especially amino acids and complexons. The study of the processes of complexation of amino acids with f-element cations provides valuable information for solving problems of supramolecular chemistry, molecular recognition and chiral sensitivity of biological substrates. As a rule, f-elements are not components of biopolymers, but they are spectral label probes, which are important in the bioinorganic chemistry of metals. Quantitative estimation of the stability of complexes is necessary, first of all, to search for an internal connection between the constants themselves and then to find correlations between the stability of complexes and the properties of the complexing agent, the ligand, and the system as a whole. Such correlation dependencies make it possible to calculate a priori, or at least estimate the stability constants of new complexes, and also to better understand the influence of the nature of the chemical bond and the properties of the system as a whole on the formation and stability of complex compounds. In the present work, the complexation of neodymium, lanthanum with L-asparaginat ion and samarium, cerium with L-leucinat ion at 298.15 K and ionic strength values of 0.5 mol/l was studied by potentiometric titration and the stability constants of the complexes formed were determined. The values of the stability constants found allow us to perform rigorous thermodynamic calculations of the equilibria of these amino acids in salt solutions. The data obtained, in particular, can be used to reliably interpret the results of calorimetric studies of the complexation of lanthanides with the participation of the studied amino acids.Forcitation:Lytkin A.I., Chernyavskaya N.V., Smirnova D.K. Stability constants of L-asparagine and L-leucine complexes with some lanthanide in aqueous solutions at 298.15 K. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 1. P. 37-41

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