A family of ligands derived from bis(amino amides) containing aliphatic spacers has been prepared, and their protonation and stability constants for the formation of Cu(2+) complexes have been determined potentiometrically. Important differences are associated to both the length of the aliphatic spacer and the nature of the side chains derived from the amino acid. In general, ligands containing...

E rhard U hlem ann*, Alwin Friedrich, G erald Hinsche, W ulfhard Mickler, Uwe Schilde Institut für Anorganische Chemie und Didaktik der Chemie. Universität Potsdam, Postfach 601553, D-14415 Potsdam Z. Naturforsch. 50b, 37-42 (1995); eingegangen am 11. Juli 1994 3-Phenyl-4-benzoyl-5-isoxazolone, Crystal Structure, Thermal Stability, Complex Stability Constants, Dioxane/Water-Mixtures Acid consta...

The polarographic study of Cd(II) with L-Tyrosine has been investigated in aqueous organic solvent mixtures at 300K. The Dimethyl sulphoxide and Dimethyl formamide solvents have been used with water to study the effect of solvents on the stability of complexes. Cadmium(II) formed 1:1, 1:2 and 1:3 complexes with L-Tyrosine in the aqueous-organic solvent mixture i.e. DMSO and DMF. The stability c...

Quantitative indication of the process of forming a complex comes from the evaluation of the stability constants which characterize the equilibria corresponding to the successive addition of ligands. A technique involving the use of paper electrophoresis is described for the study of binary complex system in solution. The first and second stability constants of metal(II) – sarcosine complexes w...

acid complexes were determined. The dissociation constants of the amino acids determined are; alanine (10.29), arginine (12.02), asparagine (9.39), glycine (9.87), histidine (7.01), lysine (9.28), methionine (9.68), phenylalanine (9.61), proline (10.53), threonine (10.31), tryptophan (9.77), and valine (10.28). The ratio of metal to amino acid determined for the complexes is 1:3, except for Cu ...

The complexation of Cd2+ by diallyl disulfide (DADS) and diallyl sulfide (DAS) has been studied by differential pulse voltammetry. Stability constants, (log β), of the 1:1 (PbL) and 1:2 (PbL2) complexes, where L = ligand, were found to be in the range of ca. 5.8 - 6.2 and 9.6 -10.6, respectively. Complex formation is accompanied with a significant decrease in the peak current and the shift of t...

Thermodynamic stability constants of the formation of complexes from the reactions of humic substances with various metals are usually used as parameters to judge the reactivities of both humic substances and metals. However, in calculating the thermodynamic stability constants, complicated processes for the acquisition of activities of components in reactions are absolutely inevitable. In this...

Study was made of host-guest complexation of neutral crown ethers with fiveand six-membered Nheteroaromatic cations and purinium cation. Complexation of tetraphenylborate with selected Nheteroaromatic cations and tropylium cation also was studied. Crown ether complexes were characterized by mass spectrometric and 1H NMR spectrometric methods and by X-ray crystallography. Fast atom bombardment m...

Interactions of certain amino acids with some metal ions have significant consequences in biological systems. Metal ions can act as co-factors in the regulation of enzymatic reactions. Interactions of metal ions with amino acid side chains or with different organic complexes is also essential for many biological events. In this study, the stability constants of 1 : 1 : 1 ternary complexes of Cu...

The synthesis of ligand L based on a 2,6-bis[(N,N-bis(methylene phosphonic acid)aminomethyl] pyridine scaffold is described. Potentiometry combined with UV-Vis absorption spectrophotometric titrations were used to determine the protonation constants of the ligand and the stability constants of its corresponding Cu(II), Ni(II), Zn(II) and Ga(III) cations (0.1 M NaClO(4), 25.0 °C). The physico-ch...