Critical evaluation of the stability constants of metal complexes of amino acids with polar side chains (Technical Report)

1995 ◽  
Vol 67 (7) ◽  
pp. 1117-1240 ◽  
Author(s):  
G. Berthon
2005 ◽  
Vol 77 (8) ◽  
pp. 1445-1495 ◽  
Author(s):  
Giorgio Anderegg ◽  
Francoise Arnaud-Neu ◽  
Rita Delgado ◽  
Judith Felcman ◽  
Konstantin Popov

Available experimental data on stability constants of proton (hydron) and metal complexes for seven complexones of particular biomedical and environmental interest: iminodiacetic acid [2,2'-azanediyldiacetic acid, IDA], (methylimino)diacetic acid [2,2'-(methylazanediyl)diacetic acid, MIDA]; 2,2',2'',2'''-{[(carboxymethyl)azanediyl]bis[(ethane-1,2-diyl)nitrilo]}tetraacetic acid (DTPA), 3,6,9,12-tetrakis(carboxymethyl)-3,6,9,12-tetraazatetradecanedioic acid (TTHA); 2,2',2''-(1,4,7-triazonane-1,4,7-triyl)triacetic acid (NOTA); 2,2',2'',2'''-(1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetraacetic acid (DOTA); 2,2',2'',2'''-(1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetrayl)tetraacetic acid (TETA), published in 1945-2000, have been critically evaluated. Some typical errors in stability constant measurements for particular complexones are summarized. Higher quality data are selected and presented as “Recommended” or “Provisional”.


2003 ◽  
Vol 75 (1) ◽  
pp. 71-102 ◽  
Author(s):  
Francoise Arnaud-Neu ◽  
Rita Delgado ◽  
Sílvia Chaves

Stability constants and thermodynamic functions of metal complexes of crown ethers in various solvents published between 1971 and the beginning of 2000 have been critically evaluated. The most studied crown ethers have been selected: 1,4,7,10 tetraoxacyclododecane (12C4), 1,4,7,10,13 pentaoxacyclopentadecane (15C5), and 1,4,7,10,13,16 hexaoxacyclooctadecane (18C6). The metal ions chosen are: alkali and alkaline earth metal ions, Ag+, Tl+, Cd2+, and Pb2+. The solvents considered are: water, methanol, ethanol, and their mixtures, as well as acetonitrile, N,N'-dimethylformamide, dimethylsulfoxide, and propylene carbonate. The published data have been examined and grouped into two categories, “accepted” and “rejected”. The “accepted” values were considered as: (i) recommended (R), when the standard deviations (s.d.) on the constant K or on ΔrH were inferior to 0.05 lg unit or inferior to 1 kJ mol−1, respectively; (ii) provisional (P), when s.d. is superior to 0.05 and inferior to 0.2 for lg K or s.d. is superior to 1 and inferior to 2 kJ mol−1 for ΔrH; (iii) recommended 1 (R1), if the values were obtained by a single research group, but were considered reliable in comparison with related systems, and considering that the research team usually presents R-level values for other similar systems.


2001 ◽  
Vol 73 (10) ◽  
pp. 1641-1677 ◽  
Author(s):  
Konstantin Popov ◽  
Hannu Rönkkömäki ◽  
Lauri H. J. Lajunen

Available experimental data on stability constants of proton and metal complexes for 10 phosphonic acids [methylphosphonic acid, 1-hydroxyethane-1,1-diylbisphosphonic acid, dichloromethylenebisphosphonic acid, amino-methanephosphonic acid, N-(phosphonomethyl)glycine, imino-N,N-bis(methylenephosphonic acid), N-methylamino-N,N-bis(methylenephosphonic acid), nitrilotris(methylenephosphonic acid), 1,2-diaminoethane-N,N,N´,N´-tetrakis-(methylenephosphonic acid), and diethylenetriamine-N,N,N´,N´´,N´´-pentakis-(methylenephosphonic acid)], published in 1950­1997, have been critically evaluated. For the latter phosphonate, all the data are rejected, as well as protonation constants [HL]/[H][L] for three other ligands. Higher-quality data are selected and presented as "Recommended" and "Provisional".


1949 ◽  
Vol 2 (4) ◽  
pp. 579 ◽  
Author(s):  
LE Maley ◽  
DP Mellor

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.


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