scholarly journals Studies of Binary Complexes of Tripodal Ligandcis,cis-1,3,5-tris(methylamino)cyclohexane with Cr(III) and Fe(III)

2005 ◽  
Vol 2 (1) ◽  
pp. 52-57
Author(s):  
S. Esakki Muthu ◽  
Suban K. Sahoo ◽  
Minati Baral ◽  
B. K. Kanungo
Keyword(s):  
Ionic Strength ◽  
Aqueous Medium ◽  
Molecular Mechanics ◽  
Stability Constants ◽  
Potentiometric Method ◽  
Molecular Mechanics Calculations ◽  
Tripodal Ligand ◽  
Binary Complexes ◽  
Overall Stability ◽  
Mode Of Coordination

The formation of binary complexes of Cr(III) and Fe(III) with a tripodal ligandcis,cis-1,3,5-tris(methylamino)cyclohexane (tmach) (L) has been investigated in solution. The overall stability constants oftmachwith Cr(III) and Fe(III) were determined by potentiometric method at an ionic strength of 0.1 M NaClO4at 25±1°C in aqueous medium. The formation of species like MLH25+, MLH4+, ML3+, ML(OH)2+and ML(OH)3were observed. Fe(III) was found to form more stable complexes than Cr(III). Molecular mechanics calculations were performed to explain the mode of coordination in solution.

Polarographic study of the mixed complexes of Cd(II) with oxalate and malonate ions

1988 ◽  
Vol 53 (3) ◽  
pp. 506-514 ◽  
Author(s):  
Cesar Rodríguez-Placeres ◽  
Graciliano Ruiz-Cabrera ◽  
Ana Alloza ◽  
Agustin Arévalo
Keyword(s):  
Ionic Strength ◽  
Aqueous Medium ◽  
Stability Constants ◽  
Polarographic Study ◽  
Mixed Complexes ◽  
Overall Stability

The coordinated mixed Cd(II)-oxalate-malonate system has been polarographically studied in aqueous medium. The ionic strength has been maintained constant at μ = 1.0 mol l-1 by using NaClO4. The overall stability constants, determined by using the Schaap and McMasters method, for the coordinated species [Cd(ox)(mal)]2-, [Cd(ox)(mal)2]4- and [Cd(ox)2(mal)]4- are respectively β11 = 1.3 . 104 l2 mol-2, β12 = 5.0 . 104 l3 mol-3 and β21 = 8.7 . 104 l3 mol-3. The various coordination equilibria are discussed on the basis of statistical aspects.

scholarly journals Study of Metal-1,10-Phenanthroline Complex Equilibria by Potentiometric Measurements

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Naciye Türkel
Keyword(s):  
Stability Constants ◽  
Metal Cations ◽  
Potentiometric Method ◽  
Ionic Radii ◽  
Binary Complexes ◽  
Potentiometric Measurements ◽  
Software Program ◽  
Phenanthroline Complex ◽  
The Stability ◽  
Potentiometric Data

The interaction of Sc(III), Y(III), and La(III) ions with 1,10-phenanthroline (Phen) has been investigated, using the potentiometric method at 25   and  M KNO3. Collected potentiometric data were processed by the “BEST” software program to establish the complexation model for each system. SPE software program was used to evaluate the concentration distributions of the species formed in solution. The stability constants for the binary complexes increased as the ionic radii of the metal cations decreased.

scholarly journals Thermodynamic and Spectroscopic Studies of the Complexes Formed in Tartaric Acid and Lanthanide(III) Ions Binary Systems

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1121 ◽  
Author(s):  
Michal Zabiszak ◽  
Martyna Nowak ◽  
Zbigniew Hnatejko ◽  
Jakub Grajewski ◽  
Kazuma Ogawa ◽  
...  
Keyword(s):  
Tartaric Acid ◽  
Stability Constants ◽  
Binary Systems ◽  
Equilibrium Constants ◽  
Spectroscopic Studies ◽  
Luminescence Spectroscopy ◽  
Binary Complexes ◽  
Overall Stability ◽  
The Stability

Binary complexes of tartaric acid with lanthanide(III) ions were investigated. The studies have been performed in aqueous solution using the potentiometric method with computer analysis of the data for detection of the complexes set, determination of the stability constants of these compounds. The mode of the coordination of complexes found was determined using spectroscopy, which shows: Infrared, circular dichroism, ultraviolet, visible as well as luminescence spectroscopy. The overall stability constants of the complexes as well as the equilibrium constants of the reaction were determined. Analysis of the equilibrium constants of the reactions and spectroscopic data allowed the effectiveness of the carboxyl groups in the process of complex formation.

Stabilities of Vanadyl Complexes with Methionine, Phenylalanine, and Threonine

1974 ◽  
Vol 29 (7-8) ◽  
pp. 336-338
Author(s):  
B.S. Sekhon ◽  
S.L. Chopra
Keyword(s):  
Free Energy ◽  
Ionic Strength ◽  
Stability Constants ◽  
Thermodynamic Stability ◽  
Chloride Solution ◽  
Formation Constants ◽  
Potassium Chloride Solution ◽  
Vanadyl Complexes ◽  
Overall Stability ◽  
Stepwise Formation

Abstract Stepwise formation constants corresponding to 1:1 vanadyl complexes with methionine, phenylalanine and threonine have been determined at 25 °C, and at various ionic concentrations, viz. 0.01, 0.1 and 0.3 ᴍ , maintained by the addition of potassium chloride solution. Thermodynamic stability constants have been obtained by extrapolation of log K values to zero ionic strength. Logarithms of the overall stability constants (log K (u = 0)) are 7.72 for methionine, 7.70 for phenyl­alanine and 7.44 for threonine complexes. The corresponding free energy changes (⊿G0) are - 10.53, - 10.51, - 10.15 kcal-mol-1 respectively.

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 STABILITY CONSTANTS OF COBALT (II) COMPLEXES OF TAURINE AND β-ALANINE

2018 ◽  
Vol 59 (3) ◽  
pp. 95 ◽  
Author(s):  
Sergei N. Gridchin ◽  
Ruslan F. Shekhanov ◽  
Svetlana A. Bychkova
Keyword(s):  
Ionic Strength ◽  
Stability Constants ◽  
Potentiometric Method ◽  
The Stability

The stability constants for cobalt (II) complexes of taurine and β-alanine were determinedwith the potentiometric method at 298.15K and at an ionic strength of 0.5 (KNO3).

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.

Complexes binaires du nickel(II) et du zinc(II) avec la 1-canavanine et la 1-arginine, études potentiométriques et spectroscopiques

1991 ◽  
Vol 69 (9) ◽  
pp. 1344-1351 ◽  
Author(s):  
Abdallah Albourine ◽  
Michelle Petit-Ramel ◽  
Germaine Thomas-David ◽  
Jean Jacques Vallon
Keyword(s):  
Circular Dichroism ◽  
Ionic Strength ◽  
Key Words ◽  
Stability Constants ◽  
Bidentate Ligand ◽  
Tridentate Ligand ◽  
Key Words 1 ◽  
Binary Complexes ◽  
The Stability ◽  
Circular Dichroïsm

The stability constants of binary complexes of 1-canavanine (Can) and 1-arginine (Arg) with Ni2+ and Zn2+ have been calculated at 25 °C and at ionic strength μ = 0.1 (NaNO3). This technique is completed with spectrophotometry and circular dichroïsm measurements in the ultraviolet and visible ranges. Thus we determined the molar absorbances and the molar circular dichroïsm of ligands and complexes with Ni2+ and Zn2+. Concerning the nickel(II), these measurements display three complexes, NiL, NiL2, and NiL3. 1-Canavanine, which generally has a tridentate ligand behaviour, becomes a bidentate ligand in the Ni(Can)3 complex. With regard to zinc(II), this study only displays the ZnL and ZnL2 species. Key words: 1-arginine, 1-canavanine, circular dichroïsm, nickel binary coordination, zinc binary coordination.

Some Novel Amino Acid-Schiff Bases and their Complexes Synthesis, Characterization, Solid State Conductivity Behaviors and Potentiometric Studies

2004 ◽  
Vol 59 (6) ◽  
pp. 692-698 ◽  
Author(s):  
Nurşen Sarı ◽  
Perihan Gürkan
Keyword(s):  
Amino Acid ◽  
Ionic Strength ◽  
Solid State ◽  
Aqueous Medium ◽  
Spectral Data ◽  
Schiff Bases ◽  
Stability Constants ◽  
Room Temperature ◽  
Condensation Reaction ◽  
Potentiometric Studies

Three new Schiff bases derived from the condensation reaction of thiophene-2-carbaldehyde and DL-alanine, DL-valine and DL-phenylalanine have been synthesized and their Co(II), Ni(II) and Cu(II) complexes have been prepared. The Schiff bases and the complexes have been characterized by their analytical and spectral data. The protonation constants of the Schiff bases and stability constants of the complexes have been determined potentiometrically in aqueous medium at 25 °C and 0.1 M KCl ionic strength. Solid state conductivities of the synthesized substances were using the four-probe technique on a compressed pellet at room temperature.

The conformational properties of calix[4]arenes 1h NMR and molecular mechanics calculations

1989 ◽  
Vol 86 ◽  
pp. 945-954 ◽  
Author(s):  
F. Bayard ◽  
D. Decoret ◽  
D. Pattou ◽  
J. Royer ◽  
A. Satrallah ◽  
...  
Keyword(s):  
Molecular Mechanics ◽  
1H Nmr ◽  
Molecular Mechanics Calculations ◽  
Conformational Properties
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