Polyphenol Interactions with Aluminium(III) and Iron(III): their Possible Involvement int he Podzolization Process

1985 ◽  
Vol 38 (6) ◽  
pp. 879 ◽  
Author(s):  
JA Kennedy ◽  
HKJ Powell
Keyword(s):  
Aqueous Solutions ◽  
Metal Ions ◽  
Stability Constants ◽  
Donor Site ◽  
Organic Soils ◽  
Forming Process ◽  
Aerobic Conditions ◽  
Neutral Ph ◽  
Ph Dependent ◽  
The Stability

The stability and solubility of complexes formed between AlIII , FeIII and an epicatechin dimer (B2) and an epicatechin polymer or tannin (T) have been studied. Polyphenols such as these could be active in mobilizing iron and aluminium in organic soils; they have the potential to act as bis-catecholate ligands toward these metal ions at neutral pH. However, it is established that the dimer functions only as a mono- catecholate , and its pH dependent stability constants (for aluminium) are no greater than those of catechol . Aqueous solutions of the ligands do not solubilize amorphous Fe(OH)3 significantly under aerobic conditions and the complexes of T are insoluble except at very low metal (Al, Fe) : donor site ratios. These observations are discussed in relation to the soil-forming process of podzolization.

The stability constants of ethylenediphosphinetetraacetate complexes

1982 ◽  
Vol 47 (4) ◽  
pp. 1078-1085 ◽  
Author(s):  
Jana Podlahová ◽  
Jaroslav Podlaha
Keyword(s):  
Aqueous Solutions ◽  
Metal Ions ◽  
Stability Constants ◽  
Metal Ion ◽  
Computer Programs ◽  
Data Treatment ◽  
Relative Affinity ◽  
Stability Constants Of Complexes ◽  
Soft Metal ◽  
The Stability

The stability constants of complexes formed by the anions of ethylenediphosphinetetraacetic acid and the metal ions Cu(I), Ag(I), Ca(II), Mn(II), Fe(II), Co(II), Ni(II), Zn(II), Cd(II), Hg(II), Pb(II) and La(III) were determined by various methods (mainly potentiometry and UV-VIS spectrophotometry), followed by data treatment using standard computer programs. The type and stability of the complexes formed depend mostly on the relative affinity of the particular metal ion for the two donor groups of the ligand. Unlike EDTA, the ligand is highly selective for soft metal ions, whose complexes are very stable even in strongly acidic aqueous solutions.

scholarly journals Copper(II)-complexation by non enzymatically glycated peptides

2004 ◽  
Vol 22 (SI - Chem. Reactions in Foods V) ◽  
pp. S106-S108
Author(s):  
S. T Seifert ◽  
R. Krause ◽  
K. Gloe ◽  
T. Henle
Keyword(s):  
Aqueous Solution ◽  
Metal Ions ◽  
Stability Constants ◽  
Maillard Reaction ◽  
Metal Binding ◽  
Maillard Reaction Products ◽  
Reaction Products ◽  
Nonenzymatic Glycation ◽  
The Stability

The purpose of our work was to examine the metal binding abilities of selected peptide bound Maillard reaction products (MRPs). The N<sup>α</sup>-hippuryl-protected MRPs N<sup>ε</sup>-fructoselysine and N<sup>ε</sup>-carboxymethyllysine were synthesised and measurement of stability constants for complexes formed with the physiologically important metal ions copper(II) and zinc(II) was carried out in aqueous solution (T = 298.1 K; I = 0.1M KNO<sub>3</sub>) using pH-potentiometry. The stability constants of N<sup>ε</sup>-fructoselysine and N<sup>ε</sup>-carboxymethyllysine with Cu(II) proved that new coordination centres are formed by the nonenzymatic glycation of proteins. With zinc(II) no complexation was observed. Physiological consequences are discussed, but further studies are necessary in order to clarify the effects of this phenomenon.

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

scholarly journals Efficient Recovery of Noble Metal Ions (Pd2+, Ag+, Pt2+, and Au3+) from Aqueous Solutions Using N,N'-Bis(salicylidene)ethylenediamine (Salen) as an Extractant (Classic Solvent Extraction) and Carrier (Polymer Membranes)

Membranes ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 863
Author(s):  
Katarzyna Witt ◽  
Małgorzata A. Kaczorowska ◽  
Daria Bożejewicz ◽  
Włodzimierz Urbaniak
Keyword(s):  
Aqueous Solutions ◽  
Metal Ions ◽  
Noble Metal ◽  
High Resolution Mass Spectrometry ◽  
Polymer Membranes ◽  
Single Component ◽  
Molar Ratio ◽  
Efficient Recovery ◽  
The Stability ◽  
Precious Metal Ions

This paper presents the results of the first application of N,N'-bis(salicylidene)ethylenediamine (salen) as an extractant in classical liquid–liquid extraction and as a carrier in membrane processes designed for the recovery of noble metal ions (Pd2+, Ag+, Pt2+, and Au3+) from aqueous solutions. In the case of the utilization of membranes, both sorption and desorption were investigated. Salen has not been used so far in the sorption processes of precious metal ions. Recovery experiments were performed on single-component solutions (containing only one type of metal ions) and polymetallic solutions (containing ions of all four metals). The stability constants of the obtained complexes were determined spectrophotometrically. In contrast, electrospray ionization high-resolution mass spectrometry (ESI-HRMS) was applied to examine the elemental composition and charge of the generated complexes of chosen noble metal ions and salen molecules. The results show the great potential of N,N'-bis(salicylidene)ethylenediamine as both an extractant and a carrier. In the case of single-component solutions, the extraction percentage was over 99% for all noble metal ions (molar ratio M:L of 1:1), and in the case of a polymetallic solution, it was the lowest, but over 94% for platinum ions and the highest value (over 99%) for gold ions. The percentages of sorption (%Rs) of metal ions from single-component solutions using polymer membranes containing N,N'-bis(salicylidene)ethylenediamine as a carrier were highest after 24 h of the process (93.23% for silver(I) ions, 74.99% for gold(III) ions, 69.11% and 66.13% for palladium(II) and platinum(II) ions, respectively), similar to the values obtained for the membrane process conducted in multi-metal solutions (92.96%, 84.26%, 80.94%, and 48.36% for Pd(II), Au(III), Ag(I), and Pt(II) ions, respectively). The percentage of desorption (%Rdes) was very high for single-component solutions (the highest, i.e., 99%, for palladium solution and the lowest, i.e., 88%, for silver solution), while for polymetallic solutions, these values were slightly lower (for Pt(II), it was the lowest at 63.25%).

Stability constants and spectral studies of complexes of 2-hydroxy-5-methylazobenzene-2′-carboxylic acid with some divalent metal ions

1984 ◽  
Vol 62 (11) ◽  
pp. 2299-2301
Author(s):  
C. Mahalingam ◽  
J. K. Sthapak ◽  
D. D. Sharma ◽  
R. L. Tiwari ◽  
Smita Sthapak
Keyword(s):  
Carboxylic Acid ◽  
Metal Ions ◽  
Metal Complexes ◽  
Stability Constants ◽  
Divalent Metal ◽  
Reflectance Spectra ◽  
Spectral Studies ◽  
Divalent Metal Ions ◽  
The Stability

The stability constants of metal complexes of 2-hydroxy-5-methylazobenzene-2′-carboxylic acid have been determined spectrophotometrically. These follow the Irving–Williams sequence: log KOH(H) = 10.67, log K1(Co) = 9.02, log K1(Ni) = 9.68, log K1(Cu) = 13.37, log K1(Zn) = 7.58, and [Formula: see text]The chelates of Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), and [Formula: see text] with the dye have been prepared and characterized on the basis of their ir and reflectance spectra.

On the Hydrolysis of Tetravalent Metal Ions

2000 ◽  
Vol 663 ◽  
Author(s):  
C. Ekberg ◽  
P. Brown ◽  
J. Comarmond ◽  
Y. Albinsson
Keyword(s):  
Metal Ions ◽  
Stability Constants ◽  
Safety Assessment ◽  
Experimental Conditions ◽  
Polymeric Species ◽  
The Stability ◽  
Hydrolysis Of

ABSTRACTThe stability constants of the hydroxide complexes of zirconium(IV) and uranium(IV) have been measured at 15, 25 and 35°C [in 1.0 mol dm−3 (Na, H)ClO4] using potentiometry. For zirconium(IV), the results indicate the presence of Zr(OH)3+ and the polymeric species Zr3(OH)48+ and Zr4(OH)88+ whereas the results for uranium(IV) indicate the presence of U(OH)3+ and the polymeric species U4(OH)124+. The hydrolysis of both metal ions was studied at three temperatures allowing the determination of ΔH° and ΔS° of reaction for each species. The results were compared with previous results determined for thorium(IV) under the same experimental conditions to ascertain whether thorium should be used as an analogue for other tetravalent metal ions in safety assessment studies of nuclear repositories.

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