Ternary complexes in solution. 35. Intramolecular hydrophobic ligand-ligand interactions in mixed ligand complexes containing an aliphatic amino acid

1980 ◽  
Vol 102 (9) ◽  
pp. 2998-3008 ◽  
Author(s):  
Beda E. Fischer ◽  
Helmut Sigel
Keyword(s):  
Amino Acid ◽  
Ternary Complexes ◽  
Mixed Ligand ◽  
Mixed Ligand Complexes ◽  
Aliphatic Amino Acid ◽  
Ligand Interactions ◽  
Hydrophobic Ligand

scholarly journals Synthesis and spectral characterizations of vanadyl(ii) and chromium(iii) mixed ligand complexes containing metformin drug and glycine amino acid

2021 ◽  
Vol 19 (1) ◽  
pp. 735-744
Author(s):  
Samar O. Aljazzar
Keyword(s):  
Amino Acid ◽  
Type Ii Diabetes ◽  
Mixed Ligand ◽  
Mixed Ligand Complexes ◽  
Spectroscopic Techniques ◽  
Nanoscale Structures ◽  
Pyramidal Geometry ◽  
Effective Drugs ◽  
Square Pyramidal Geometry ◽  
Spectral Characterizations

Abstract Metformin is one of the most effective drugs for the treatment of type II diabetes. Two new mixed ligand complexes of vanadyl(ii) and chromium(iii) ions with the general formula [VOL1L2]SO4 and [CrL1L2(Cl)2]Cl, respectively, where L1 is the metformin and L2 is the glycine amino acid, have been synthesized in MeOH solvent with 1:1:1 stoichiometry and characterized by several spectroscopic techniques. The spectroscopic data suggested that the [VOL1L2]SO4 complex possesses a square pyramidal geometry, where the [CrL1L2(Cl)2]Cl complex possesses an octahedral geometry. The L1 ligand coordinated to the VO(ii) and Cr(iii) ions via the N atoms of the imino (‒C═NH) groups, where the L2 ligand coordinated via the O atom of the carboxylate group (COO) and the N atom of the amino group (NH2). The interaction of ligands L1 and L2 with the metal ions leads to complexes that have organized nanoscale structures with a main diameter of ∼14 nm for the [CrL1L2(Cl)2]Cl complex and ∼40 nm for the [VOL1L2]SO4 complex.

Thermal properties of some pyrimidine, purine, amino-acid and mixed ligand complexes

2013 ◽  
Vol 551 ◽  
pp. 164-174 ◽  
Author(s):  
Mamdouh S. Masoud ◽  
Ahmed M. Ramadan ◽  
Ghada M. El-Ashry
Keyword(s):  
Thermal Properties ◽  
Amino Acid ◽  
Mixed Ligand ◽  
Mixed Ligand Complexes

Ternary Complexes in Solution, XII. Models for Biological Mixed-Ligand Complexes: 2,2′-Bipyridyl-Cu2+-Oligoglycine Systems

1972 ◽  
Vol 27 (4) ◽  
pp. 353-364 ◽  
Author(s):  
Helmut Sigel ◽  
Rolf Griesser ◽  
Bernhard Prijs
Keyword(s):  
Coordination Sphere ◽  
Ternary Complexes ◽  
Mixed Ligand ◽  
Amide Group ◽  
Amide Proton ◽  
Mixed Ligand Complexes ◽  
Apical Position ◽  
Binary Complexes ◽  
The Stability ◽  
Ph Range

The stability constants of the binary Cu2+ complexes of glycine amide, diglycine, diglycine amide, triglycine, and tetraglycine were determined, as were those of the mixed-ligand Cu2+ systems containing 2,2′-bipyridyl and one of the mentioned oligoglycines. The results evidence that all these complexes have the same structure and, therefore, the binding sites of the ligands have to be the terminal amino group and the oxygen of the neighbored amide group. The stability differences between the ternary and the binary complexes are in agreement with this interpretation. It is of interest to note that these ternary complexes are significantly more stable than expected on statistical reasons. With increasing pH, the amide groups in the binary complexes are successively deprotonated. Thus, with tetraglycine finally all three amide protons are displaced, and the amide nitrogens are bound to the square-planar coordination sphere of Cu2+. As in the Cu2+-2,2′-bipyridyl 1 : 1 complex, only two coordination positions are left for the binding of the oligoglycine, in the tenary complexes, only one amide group can be deprotonated. An increase in pH with deprotonation of other amide groups leads to a displacement of 2,2′-bipyridyl, i. e. the simple binary complexes result. No evidence could be observed for the coordination of a deprotonated amide group to an apical position of the coordination sphere of Cu2+. Additionally, while the displacement of the first amide proton in the several binary Cu2+ oligoglycine complexes occurs over a large pH range (4 to 7), the deprotonation in all the mixed-ligand complexes takes place at pH approximately 8.

Potentiometric Studies On Mixed Ligand Complexes

1972 ◽  
Vol 27 (3) ◽  
pp. 308-311 ◽  
Author(s):  
R. C. Sharma ◽  
J. P. Tandon
Keyword(s):  
Ternary Complexes ◽  
Mixed Ligand ◽  
Mixed Ligand Complexes ◽  
Potentiometric Studies ◽  
Hydroxy Acids

Potentiometric evidences have been cited for the formation of 1:1:1, ternary complexes in the systems La (III) -NTA-Hydroxy acids (where hydroxy acids = malic, tartaric, 1-hydroxy 2-naphthoic and 2-hydroxy-3 naphthoic acids).

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