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 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 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.

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.

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.

Relative complexing tendencies of O—O, O—N, and O—S donor (secondary) ligands in some lanthanide–EDTA mixed-ligand complexes

1986 ◽  
Vol 64 (5) ◽  
pp. 865-870 ◽  
Author(s):  
Sudhir N. Limaye ◽  
Mahesh C. Saxena
Keyword(s):  
Ionic Strength ◽  
Association Constants ◽  
Mixed Ligand ◽  
Mixed Ligand Complexes ◽  
Binary Complex ◽  
Electrostatic Repulsion ◽  
Aromatic Ligand ◽  
Titration Technique ◽  
Metal Ligand ◽  
Secondary Ligand

Metal–ligand association constants of 1:1 binary (ML) and 1:1:1 ternary (MAL) complexes of the type [Formula: see text] (where M = La3+, Ce3+, Pr3+, Nd3+, or Sm3+; A = primary ligand = EDTA; L = secondary ligand = O—O, O—N, O—S donor aliphatic or aromatic ligand) have been determined potentiometrically by the Irving–Rossotti titration technique at ionic strength 0.2 (mol dm−3 NaClO4) and 25 °C. Differences between log KML and log KMAL are negative; this may be chiefly due to electrostatic repulsion between the primary binary complex and the incoming secondary ligand during the formation of the mixed-ligand complexes. The relative complexing tendencies of various secondary ligands have been found to follow the sequence O—O donor (aromatic) > O—N donor > O—O donor (aliphatic) ≥ O—S donor.

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