scholarly journals Stability Constants of Mixed Ligand Complexes of Transition Metal(II) Ions with Salicylidene-4-methoxyaniline as Primary Ligand and 5-Bromosalicylidene-4-nitroaniline as Secondary Ligand

2011 ◽  
Vol 8 (4) ◽  
pp. 1765-1769 ◽  
Author(s):  
N. G. Nadkarni ◽  
K. V. Mangaonkar
Keyword(s):  
Ionic Strength ◽  
Stability Constants ◽  
Ternary Complexes ◽  
Mixed Ligand ◽  
Mixed Ligand Complexes ◽  
Water Medium ◽  
Binary And Ternary Complexes ◽  
Binary Complexes ◽  
The Stability ◽  
Secondary Ligand

Binary and ternary complexes of the type M-Y and M-X-Y [M = Mn(II), Ni(II), Cu(II) and Zn(II); X = salicylidene-4-methoxyaniline and Y=5-bromosalicylidene-4-nitroaniline] have been examined pH-metrically at 27±0.5 °C and at constant ionic strength, μ= 0.1 M (KCl) in 75 : 25(v/v) 1,4-dioxne-water medium. The stability constants for binary (M-Y) and ternary (M-X-Y) systems were calculated. The relative stability (Δ log KT) values of the ternary complexes with corresponding binary complexes for all the metal(II) ions in the present study found to be negative indicating that ternary 1:1:1 (M-X-Y) complexes are less stable than binary 1:1 (M-Y) complexes. In the ternary system studied, the order of stability constants of mixed ligand complexes with respect to the metal ions was found to be Cu(II) > NI(II) > Mn(II) > Zn(II); which is same as in the corresponding binary (M-Y) systems.

scholarly journals Stability Constants of Mixed Ligand Complexes of Transition Metal(II) ions with N-(2-hydroxybenzylidene)-2,3-dimethylaniline as Primary Ligand and N-(2-hydroxy-1-naphthylidene)-4-nitroaniline as Secondary Ligand

2011 ◽  
Vol 8 (2) ◽  
pp. 859-862 ◽  
Author(s):  
A. K. Mapari ◽  
K. V. Mangaonkar
Keyword(s):  
Ionic Strength ◽  
Transition Metal ◽  
Stability Constants ◽  
Ternary Complexes ◽  
Mixed Ligand ◽  
Mixed Ligand Complexes ◽  
Water Medium ◽  
Binary And Ternary Complexes ◽  
The Stability ◽  
Secondary Ligand

Binary and ternary complexes of the type M-Y and M-X-Y [M=Co(II), Ni(II), Cu(II) and Zn(II); X=N-(2-hydroxybenzylidene)-2,3-dimethylaniline and Y =N-(2-hydroxy-1-naphthylidene)-4-nitroaniline] have been examined pH-metrically at 27±0.5 °C and at constant ionic strength, μ=0.1 M (KCl) in 75:25(v/v) 1,4-dioxne-water medium. The stability constants for binary (M-Y) and ternary (M-X-Y) systems were calculated.

scholarly journals Stability Constants of Mixed Ligand Complexes of Transition Metal(II) Ions withN-(2-Hydroxy-1-naphthylidene)-2,6-diisopropylaniline as Primary Ligand and N-(2-Hydroxybenzylidene)-2,3-dimethylaniline as Secondary Ligand

2011 ◽  
Vol 8 (1) ◽  
pp. 123-126
Author(s):  
A. K. Mapari ◽  
K. V. Mangaonkar
Keyword(s):  
Transition Metal ◽  
Stability Constants ◽  
Ternary Complexes ◽  
Mixed Ligand ◽  
Mixed Ligand Complexes ◽  
Water Medium ◽  
Binary And Ternary Complexes ◽  
Secondary Ligand

Binary and ternary complexes of the type M-Y and M-X-Y [M = Co(II), Ni(II), Cu(II) and Zn(II); X = N-(2-hydroxy-1-naphthylidene)-2,6-diisopropylaniline and Y =N-(2-hydroxybenzylidene)-2,3-dimethylaniline] have been examined pH-metrically at 27±0.5°C and µ = 0.1 M in 75: 25% (v/v) 1,4-dioxne-water medium. The logarithms of the values of stability constants for binary (M-Y) and for ternary (M-X-Y) systems were calculated.

scholarly journals Stability Studies of Transition Metal Chelates of 5-Bromosalicylidene-4-methoxyaniline andSalicylidene-2,3-dimethylaniline as Ligands

2011 ◽  
Vol 8 (4) ◽  
pp. 1911-1915
Author(s):  
N. G. Nadkarni ◽  
K. V. Mangaonkar
Keyword(s):  
Ionic Strength ◽  
Transition Metal ◽  
Stability Constants ◽  
Metal Chelates ◽  
Ternary Complexes ◽  
Water Medium ◽  
Stability Studies ◽  
Binary And Ternary Complexes ◽  
Transition Metal Chelates ◽  
The Stability

Binary and ternary complexes of the type M-Y and M-X-Y [M = Mn(II), Ni(II), Cu(II) and Zn(II); X = 5-bromosalicylidene-4-methoxyaniline and Y = salicylidene-2,3-dimethylaniline] have been examined pH-metrically at 27±0.5°C and at constant ionic strength, μ = 0.1 M (KCl) in 75 : 25(v/v) 1,4-dioxne-water medium. The stability constants for binary (M-Y) and ternary (M-X-Y) systems were calculated.

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.

Interligand interaction in ternary complexes of Zn(II) and Cd(II) with dipeptides and aminoacids

1994 ◽  
Vol 72 (4) ◽  
pp. 1107-1110 ◽  
Author(s):  
Alexander Varghese Vaidyan ◽  
Pabitra K. Bhattacharya
Keyword(s):  
Ionic Strength ◽  
Aqueous Medium ◽  
Computer System ◽  
Stability Constants ◽  
Ternary Complexes ◽  
Binary And Ternary Complexes ◽  
The Stability ◽  
Interligand Interaction

The stability constants of binary and ternary complexes [MA], [Ma2], and [MAL] (where M = Zn(II) or Cd(II); A = glycylglycine, glycyl L-alanine, glycyl L-leucine; L = α-alanine phenylalanine, tyrosine, tryptophan, or L-histidine) in aqueous medium have been determined potentometrically at 25 °C and an ionic strength of 0.2 M NaClO4 (0.2 mol dm−3) using a computer system. It is observed that Δ log K of MAL complexes has low negative or positive values. Probable reasons have been discussed.

scholarly journals Thermodynamics of binary and ternary complexes of 3-amino-1, 2, 4-triazole and aminoacids with Ni(II) and Co(II) metal ions

2005 ◽  
Vol 70 (8-9) ◽  
pp. 1057-1066 ◽  
Author(s):  
Ayse Erçag ◽  
Tuba Sismanoglu ◽  
Suheyla Pura
Keyword(s):  
Ionic Strength ◽  
Aqueous Solutions ◽  
Glutamic Acid ◽  
Driving Force ◽  
Ternary Complex ◽  
Ternary Complexes ◽  
Binary And Ternary Complexes ◽  
Enthalpy Changes ◽  
Binary Complexes ◽  
The Stability

The stability constants of the 1:1 binary complexes of Ni(II) and Co(II) with 3-amino-1,2,4-triazole (AT), leucine (Leu) and glutamic acid (Glu), and the 1:1:1 ternary complex of them and the protonation constants of the ligands were determined potentiometrically at a constant ionic strength of I = 0.10 mol L-1 (NaClO4) in aqueous solutions at 15.0 and 25.0 ?C. The thermodynamic parameters ?Gf0, ?Hf0 and ?Sf0 are reported for the formation reactions of the complexes. The enthalpy changes of all the complexations were found to be negative but the entropy changes positive. While the driving force for the formation of the Ni(II), Co(II) ? AT complexes is the enthalpy decrease, the driving force for the ternary complexes of AT is the entropy increase.

scholarly journals Electrometric Investigation of the Nature and Stability of Mixed Ligand Complexes of L-Ornithine and 1,10-Phenanthroline with Some Essential Metal Ions in Aqua-TBAB or PEG-400 Surfactant

2021 ◽  
Author(s):  
Atnafu Guadie Assefa ◽  
Molla Tefera Negash ◽  
Mulugeta Legesse Akele ◽  
Bewketu Mehari Workneh ◽  
Ayal Adugna Mesfin ◽  
...  
Keyword(s):  
Metal Ions ◽  
Stability Constants ◽  
Tetrabutylammonium Bromide ◽  
Mixed Ligand ◽  
Mixed Ligand Complexes ◽  
Essential Metal ◽  
Peg 400 ◽  
Chemical Models ◽  
Binary Complexes ◽  
The Stability

Abstract Background Despite the availability of information about the effect of aqua-surfactants media on the stability of binary complexes, data related to mixed ligand complexes of Phen and Orn with essential metals in aqua-surfactant medium is scarce. The aim of this study was, to determine the stabilities of the mixed ligand complexes of essential metal ions (Co2+, Ni2+, Cu2+) with Phen and Orn in aqua-TBAB and PEG-400 surfactants with an eye on the prediction of the bioavailability of the metal complexes. Results Complexes of some essential metal (M) ions (Co2+, Ni2+, Cu2+) of L-ornithine (L) and 1,10-phenanthroline (X) ligands in various concentrations (0.0–2.5% v/v) of aqueous tetrabutylammonium bromide (TBAB) or polyethylene glycol-400 (PEG-400) surfactant were synthesized pH-metrically at 298 K and 0.16 mol L− 1 ionic strength. The relative amounts of L:M:X were 2.5:1.0:2.5; 5.0:1.0:2.5; 2.5:1.0:5.0. The data acquisition of acid-base equilibria and determination of stability constants were performed using MINIQUAD75 algorithm. The distribution patterns of the complexes with varying pH and compositions of surfactants were presented from the plots of SIM run data. Conclusions The best fit chemical models were found to be MLXH, MLX2H in the lower pH, and MLX, ML2X in the higher pH ranges for all the metals. The logged values of stability constants decreased linearly with increasing concentrations of surfactants, indicating the dominance of electrostatic factors. The log of the disproportionation constant and the change in log values of the mixed ligand constant indicated additional stability of the mixed ligand complexes, compared to the parent binary complexes due to interactions outside the coordination sphere. This makes the mixed ligand complexes more amenable to metal ion storage and transport and threw light to have information on the less stable binary complexes easily bioavailability while the mixed ligand complexes could be stored and transported in the bio-fluids. Significant change on the magnitudes of the stability constants, high values of standard deviation and rejection of some of the proposed chemical models were observed due to pessimistic error, indicating the sufficiency of the models to represent the data and accuracy of the method employed.

scholarly journals Characterization by Potentiometric Procedures of the Stability Constants of the Binary and Ternary Complexes of Cu(II) and Duloxetine Drug with Amino Acids

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Amal M. Al-Mohaimeed ◽  
Asma A. Alothman
Keyword(s):  
Amino Acids ◽  
Stability Constants ◽  
Formation Constants ◽  
Ternary Complexes ◽  
Planar Geometry ◽  
Binary And Ternary Complexes ◽  
Mass Spectral ◽  
Binary Complexes ◽  
Potentiometric Titration Method ◽  
The Stability

Potentiometric titration method has been used to define stoichiometries and stability constants of ternary complexes of Cu(II) with duloxetine (D) and some selected amino acids (L). The protonation constants of the ligands and the stability constants of the binary and ternary complexes of Cu(II) with the ligands were calculated from the potentiometric data using the HYPERQUAD program. The formation constants of the complexes formed in aqueous solutions and their concentration distributions as a function of pH were evaluated at 25°C and ionic strength 0.10 mol·L−1 NaNO3. Respective stabilities of ternary complexes have been determined compared with the corresponding binary complexes in terms of Δlog  K and %R.S. values. A novel binary and ternary duloxetine (D) drug with glycine and its Cu(II) complexes has been synthesized and characterized by several spectroscopic methods. Electronic spectra and magnetic susceptibility measurements reveal square planar geometry for both complexes. The elemental analyses and mass spectral data have justified the [Cu(D)(Gly)] and [Cu(D)Cl(H2O)] composition of complexes, where D = duloxetine and Gly = glycine. The EPR spectra of Cu(II) complexes support the mononuclear structures. Thermal properties and decomposition kinetics of Cu(II) complexes are investigated.

scholarly journals Stability Constants of Mixed Ligand Complexes of Nickel(II) with Adenine and Some Amino Acids

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Naciye Türkel
Keyword(s):  
Aqueous Solution ◽  
Amino Acids ◽  
Ternary Complex ◽  
Coordination Complexes ◽  
Ternary Complexes ◽  
Mixed Ligand ◽  
Relative Stabilities ◽  
Binary And Ternary Complexes ◽  
Binary Complexes ◽  
Essential Trace Elements

Nickel is one of the essential trace elements found in biological systems. It is mostly found in nickel-based enzymes as an essential cofactor. It forms coordination complexes with amino acids within enzymes. Nickel is also present in nucleic acids, though its function in DNA or RNA is still not clearly understood. In this study, complex formation tendencies of Ni(II) with adenine and certain L-amino acids such as aspartic acid, glutamic acid, asparagine, leucine, phenylalanine, and tryptophan were investigated in an aqueous medium. Potentiometric equilibrium measurements showed that both binary and ternary complexes of Ni(II) form with adenine and the above-mentioned L-amino acids. Ternary complexes of Ni(II)-adenine-L-amino acids are formed by stepwise mechanisms. Relative stabilities of the ternary complexes are compared with those of the corresponding binary complexes in terms ofΔlog10⁡K,log10⁡X, and % RS values. It was shown that the most stable ternary complex is Ni(II):Ade:L-Asn while the weakest one is Ni(II):Ade:L-Phe in aqueous solution used in this research. In addition, results of this research clearly show that various binary and ternary type Ni(II) complexes are formed in different concentrations as a function of pH in aqueous solution.

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