Norleucine metal complexes: comments on their equilibrium constants data

2018 ◽  
Vol 38 (2) ◽  
pp. 43-48
Author(s):  
Ahmed E. Fazary ◽  
Mutasem Z. Bani-Fwaz ◽  
Khaled F. Fawy ◽  
Taher Sahlabji ◽  
Nasser S. Awwad ◽  
...  
Keyword(s):  
Amino Acid ◽  
Metal Complexes ◽  
Stability Constants ◽  
Equilibrium Constants ◽  
Complexation Equilibria ◽  
Discussion Article ◽  
Complex Chemistry

AbstractThis discussion article summarizes all protonation and stability constants data found in the literature for nonproteinl-norleucine amino acid and its metal complexes. The results of approximately 18 published articles discussing the protonation and complexation equilibria ofl-norleucine using different techniques and software were presented to comprehend the data on the grounds of modern aspects ofl-norleucine complex chemistry.

The Relative Stability of Internal Metal Complexes. II. Metal Derivatives of 8-Hydroxyquinoline 5-Sulphonic Acid and a Series of Monocarboxylic Mono-α-amino Acids including Histidine

1949 ◽  
Vol 2 (4) ◽  
pp. 579 ◽  
Author(s):  
LE Maley ◽  
DP Mellor
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Metal Complexes ◽  
Stability Constants ◽  
Sulphonic Acid ◽  
Mathematical Treatment ◽  
Metal Derivatives ◽  
A Chain ◽  
The Stability ◽  
Derivatives Of

Stability constants of ct series of metal complexes derived from the series of α-amino acids, glycine, alanine, leucine, valine, histidine, and 8-hydroxyquinoline 5-sulphonic acid have been determined by an electrometric method. The metals fall in the same order, as regards stability of their complexes, as was found for the chelating molecules studied in Part I of this series. As the length of the a chain of the amino acid increases, there is a small decrease in the stability of the amino acid complexes of any one metal. The cobalt II complex of histidine is much more stable than cobalt II complexes derived from any of the other α-amino acids. It is suggested that this explains why histidine is able to nullify the inhibiting action of cobalt on the growth and respiration of various aerobic and anaerobic organisms. Though there is no great difference in the stability of corresponding metal complexes derived from 8-hydroxyquinoline and 8-hydroxyquinoline 5-sulphonic acid (when allowance is made for different solvents used in making the measurements), there is a marked difference in the bacteriostatic action of these two chelating molecules. A reason for this difference is suggested. The stability constants of any chelating reaction involving the liberation of any number of hydrogen ions can be evaluated by using the generalized mathematical treatment which has been set out in this series of papers.

Constraints on the determination of stability constants for metal complexes. II. The iron(III) phenolates

1968 ◽  
Vol 46 (14) ◽  
pp. 2385-2392 ◽  
Author(s):  
W. A. E. McBryde
Keyword(s):  
Metal Complexes ◽  
Stability Constants ◽  
Equilibrium Constants ◽  
Low Ph ◽  
Experimental Results ◽  
Good Precision ◽  
Acidity Constants ◽  
Extinction Coefficients ◽  
Molar Extinction Coefficients

Stability constants have been measured spectrophotometrically for the 1:1 complexes of iron(III) with phenol and five derivatives in background solutions having two different compositions, 0.027 M NaClO4 and 0 5 M KNO3 Conditional acidity constants for these phenols in the second of these media were also determined The experimental results were treated in two different ways to obtain values of the equilibrium constants and the molar extinction coefficients of the complexes It is apparent that the equilibrium in these cases must be studied under conditions, such as low pH and low concentration of iron, which militate against good precision in the results

Extraction of strontium and barium salts by the nitrobenzene solution of dicarbolide in the presence of glymes

1985 ◽  
Vol 50 (3) ◽  
pp. 581-599 ◽  
Author(s):  
Petr Vaňura ◽  
Emanuel Makrlík
Keyword(s):  
Stability Constants ◽  
Organic Phase ◽  
Equilibrium Constants ◽  
Minor Role ◽  
Nitrobenzene Solution ◽  
Ligand Structure ◽  
Stability Constants Of Complexes ◽  
Separation Factors ◽  
The Stability ◽  
A Minor

Extraction of microamounts of Sr2+ and Ba2+ (henceforth M2+) from the aqueous solutions of perchloric acid (0.0125-1.02 mol/l) by means of the nitrobenzene solutions of dicarbolide (0.004-0.05 mol/l of H+{Co(C2B9H11)2}-) was studied in the presence of monoglyme (only Ba2+), diglyme, triglyme, and tetraglyme (CH3O-(CH2-CH2O)nCH3, where n = 1, 2, 3, 4). The distribution of glyme betweeen the aqueous and organic phases, the extraction of the protonized glyme molecule HL+ together with the extraction of M2+ ion and of the glyme complex with the M2+ ion, i.e., ML2+ (where L is the molecule of glyme), were found to be the dominating reactions in the systems under study. In the systems with tri- and tetraglymes the extraction of H+ and M2+ ions solvated with two glyme molecules, i.e., the formation of HL2+ and ML22+ species, can probably play a minor role. The values of the respective equilibrium constants, of the stability constants of complexes formed in the organic phase, and the theoretical separation factors αBa/Sr were determined. The effect of the ligand structure on the values of extraction and stability constants in the organic phase is discussed.

scholarly journals Stability of Metal Complexes with a Ligand of Biological Interest: Noradrenaline

1999 ◽  
Vol 23 (2) ◽  
pp. 90-91
Author(s):  
Christian Gérard ◽  
Hanane Chehhal ◽  
Michel Aplincourt
Keyword(s):  
Metal Complexes ◽  
Equilibrium Constants ◽  
Biological Interest ◽  
Potentiometric Measurements

Stoichiometry, equilibrium constants and spectra of iron(III) complexes with noradrenaline have been determined from spectrophotometric measurements; in addition equilibrium constants of complexes with MgII, CdII and PbII have been determined from potentiometric measurements.

Equilibrium constants of metal amino acid complexes

Polyhedron ◽  
1990 ◽  
Vol 9 (5) ◽  
pp. 665-668 ◽  
Author(s):  
F. Rey ◽  
J.M. Antelo ◽  
F. Arce ◽  
F.J. Penedo
Keyword(s):  
Amino Acid ◽  
Equilibrium Constants ◽  
Amino Acid Complexes

Metal complexes of polymers with amino acid residues. formation, stability and controlled biological activity

1990 ◽  
Vol 14 (1) ◽  
pp. 61-70 ◽  
Author(s):  
V.A. Lee ◽  
R.I. Musin ◽  
R.I. Tashmukhamedov ◽  
M.I. Shtilman ◽  
S.Sh. Rashidova
Keyword(s):  
Biological Activity ◽  
Amino Acid ◽  
Metal Complexes ◽  
Amino Acid Residues
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