Complexation of Dioxovanadium(V) with Methyliminodiacetic Acid in NaClO4Aqueous Solutions at Different Ionic Strengths by Using an Extended Debye−Hückel Equation, Specific Ion Interaction Theory, and Parabolic Equations

2010 ◽  
Vol 55 (2) ◽  
pp. 882-888 ◽  
Author(s):  
Kavosh Majlesi ◽  
Saghar Rezaienejad
Keyword(s):  
Parabolic Equations ◽  
Interaction Theory ◽  
Specific Ion Interaction Theory ◽  
Methyliminodiacetic Acid

scholarly journals Understanding the Solution Behavior of Epinephrine in the Presence of Toxic Cations: A Thermodynamic Investigation in Different Experimental Conditions

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 511 ◽  
Author(s):  
Francesco Crea ◽  
Concetta De Stefano ◽  
Anna Irto ◽  
Gabriele Lando ◽  
Stefano Materazzi ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Complex Formation ◽  
Formation Constants ◽  
Titration Calorimetry ◽  
Interaction Theory ◽  
Thermodynamic Investigation ◽  
Experimental Conditions ◽  
Complex Formation Constants ◽  
Specific Ion Interaction Theory ◽  
Enthalpy Changes

The interactions of epinephrine ((R)-(−)-3,4-dihydroxy-α-(methylaminomethyl)benzyl alcohol; Eph−) with different toxic cations (methylmercury(II): CH3Hg+; dimethyltin(IV): (CH3)2Sn2+; dioxouranium(VI): UO22+) were studied in NaClaq at different ionic strengths and at T = 298.15 K (T = 310.15 K for (CH3)2Sn2+). The enthalpy changes for the protonation of epinephrine and its complex formation with UO22+ were also determined using isoperibolic titration calorimetry: ΔHHL = −39 ± 1 kJ mol−1, ΔHH2L = −67 ± 1 kJ mol−1 (overall reaction), ΔHML = −26 ± 4 kJ mol−1, and ΔHM2L2(OH)2 = 39 ± 2 kJ mol−1. The results were that UO22+ complexation by Eph− was an entropy-driven process. The dependence on the ionic strength of protonation and the complex formation constants was modeled using the extended Debye–Hückel, specific ion interaction theory (SIT), and Pitzer approaches. The sequestering ability of adrenaline toward the investigated cations was evaluated using the calculation of pL0.5 parameters. The sequestering ability trend resulted in the following: UO22+ >> (CH3)2Sn2+ > CH3Hg+. For example, at I = 0.15 mol dm−3 and pH = 7.4 (pH = 9.5 for CH3Hg+), pL0.5 = 7.68, 5.64, and 2.40 for UO22+, (CH3)2Sn2+, and CH3Hg+, respectively. Here, the pH is with respect to ionic strength in terms of sequestration.

A more realistic approach to speciation using the IUPAC Stability Constants Database

2009 ◽  
Vol 81 (9) ◽  
pp. 1585-1590 ◽  
Author(s):  
Leslie Pettit ◽  
Gwyneth Pettit
Keyword(s):  
Ionic Strength ◽  
Stability Constants ◽  
Interaction Theory ◽  
Temperature Changes ◽  
Specific Ion Interaction Theory ◽  
Realistic Approach ◽  
Lower Accuracy ◽  
Inorganic Ligands ◽  
Existing Data ◽  
General Method

The IUPAC Stability Constants Database (SC-Database), designed to contain all significant published constants, provides the most complete and accessible route to stability constants in the literature. Collection of new constants is becoming less significant since most are now measured to confirm a mechanism or to identify bonding centers, not to provide data for general use. As a result, constants are often measured less rigorously and are of lower accuracy. What are required now are critical evaluations of existing data, coupled with accurate study of a number of important and superficially simpler systems (e.g., complexes with some inorganic ligands). Calculation of species distribution curves is a major use of stability constants. Ways of reflecting possible errors in the calculated curves are now required. Historically, curves have been drawn as sharp lines, but these could only result from using the exact stability constants with an accurate model for the system. Two techniques for demonstrating the effect of errors are outlined. Constants are dependent on ionic strength and temperature changes. Specific ion interaction theory (SIT) is the most general method of compensating for ionic strength changes up to about 5 molal. Software to correct constants for ionic strength changes, prepared under recent IUPAC projects, is described.

Chemical speciation of environmentally significant metals with inorganic ligands. Part 5: The Zn2+ + OH–, Cl–, CO32–, SO42–, and PO43– systems (IUPAC Technical Report)

2013 ◽  
Vol 85 (12) ◽  
pp. 2249-2311 ◽  
Author(s):  
Kipton J. Powell ◽  
Paul L. Brown ◽  
Robert H. Byrne ◽  
Tamás Gajda ◽  
Glenn Hefter ◽  
...  
Keyword(s):  
Chemical Speciation ◽  
Formation Constants ◽  
Water Systems ◽  
Organic Ligands ◽  
Interaction Theory ◽  
Interaction Coefficients ◽  
Weakly Alkaline ◽  
Specific Ion Interaction Theory ◽  
Technical Report ◽  
Inorganic Ligands

The numerical modeling of ZnII speciation amongst the environmental inorganic ligands Cl–, OH–, CO32–, SO42–, and PO43– requires reliable values for the relevant stability (formation) constants. This paper compiles and provides a critical review of these constants and related thermodynamic data. It recommends values of log10βp,q,r° valid at Im = 0 mol·kg–1 and 25 °C (298.15 K), and reports the empirical reaction ion interaction coefficients, ∆ε, required to calculate log10βp,q,r values at higher ionic strengths using the Brønsted–Guggenheim–Scatchard specific ion interaction theory (SIT). Values for the corresponding reaction enthalpies, ∆rH, are reported where available. There is scope for additional high-quality measurements for the Zn2+ + H+ + CO32– system and for the Zn2+ + OH– and Zn2+ + SO42– systems at I > 0. In acidic and weakly alkaline fresh water systems (pH < 8), in the absence of organic ligands (e.g., humic substances), ZnII speciation is dominated by Zn2+(aq). In this respect, ZnII contrasts with CuII and PbII (the subjects of earlier reviews in this series) for which carbonato- and hydroxido- complex formation become important at pH > 7. The speciation of ZnII is dominated by ZnCO3(aq) only at pH > 8.4. In seawater systems, the speciation at pH = 8.2 is dominated by Zn2+(aq) with ZnCl+, Zn(Cl)2(aq), ZnCO3(aq), and ZnSO4(aq) as minor species. This behaviour contrasts with that for CuII and PbII for which at the pH of seawater in equilibrium with the atmosphere at 25 °C (log10 {[H+]/c°} ≈ 8.2) the MCO3(aq) complex dominates over the MCln(2–n)+ species. The lower stability of the different complexes of ZnII compared with those of CuII, PbII, and CdII is also illustrated by the percentage of uncomplexed M2+ in seawater, which is ca. 55, 3, 2, and 3.3 % of [MII]T, respectively.

The OECD/NEA TDB review of selected organic ligands

2005 ◽  
Vol 93 (11) ◽  
Author(s):  
Wolfgang Hummel ◽  
Giorgio Anderegg ◽  
Ignasi Puigdomènech ◽  
Linfeng Rao ◽  
Osamu Tochiyama
Keyword(s):  
Ionic Strength ◽  
Data Base ◽  
Nuclear Energy ◽  
Organic Ligands ◽  
Thermochemical Data ◽  
Correction Procedure ◽  
Interaction Theory ◽  
Energy Agency ◽  
Comprehensive Review ◽  
Specific Ion Interaction Theory

SummaryWithin the scope of the OECD Nuclear Energy Agency (NEA) Thermochemical Data Base Project (TDB) a comprehensive review of selected organic ligands has been carried out by the authors. The selected ligands are oxalate, citrate, ethylenediaminetetraacetate (edta) and α-isosaccharinate (isa), and the elements considered in the review are U, Np, Pu, Am, Tc, Ni, Se and Zr, as well as the necessary basic data concerning protonation of the ligands and interactions with the major competing elements Na, K, Mg and Ca. This review on organic ligands showed that the pragmatic ionic strength correction procedure, the Specific ion Interaction Theory (SIT), chosen as the default method for all NEA TDB reviews, can be applied successfully also to organic ligands. The SIT interaction parameters derived from ligand protonation data for different media,

scholarly journals Speciation Studies of Bifunctional 3-Hydroxy-4-Pyridinone Ligands in the Presence of Zn2+ at Different Ionic Strengths and Temperatures

Molecules ◽  
2019 ◽  
Vol 24 (22) ◽  
pp. 4084 ◽  
Author(s):  
Anna Irto ◽  
Paola Cardiano ◽  
Salvatore Cataldo ◽  
Karam Chand ◽  
Rosalia Maria Cigala ◽  
...  
Keyword(s):  
Equilibrium Constants ◽  
Analytical Techniques ◽  
Interaction Theory ◽  
Acid Base ◽  
Specific Ion Interaction Theory ◽  
Ligand Coordination ◽  
Dependence On Ionic Strength ◽  
Ligand Species ◽  
Metal Ligand

The acid–base properties of two bifunctional 3-hydroxy-4-pyridinone ligands and their chelating capacity towards Zn2+, an essential bio-metal cation, were investigated in NaCl aqueous solutions by potentiometric, UV-Vis spectrophotometric, and 1H NMR spectroscopic titrations, carried out at 0.15 ≤ I/mol −1 ≤ 1.00 and 288.15 ≤ T/K ≤ 310.15. A study at I = 0.15 mol L−1 and T = 298.15 K was also performed for other three Zn2+/Lz− systems, with ligands belonging to the same family of compounds. The processing of experimental data allowed the determination of protonation and stability constants, which showed accordance with the data obtained from the different analytical techniques used, and with those reported in the literature for the same class of compounds. ESI-MS spectrometric measurements provided support for the formation of the different Zn2+/ligand species, while computational molecular simulations allowed information to be gained on the metal–ligand coordination. The dependence on ionic strength and the temperature of equilibrium constants were investigated by means of the extended Debye–Hückel model, the classical specific ion interaction theory, and the van’t Hoff equations, respectively.

Sign in / Sign up

Export Citation Format

Share Document