Chelating Tendencies of some N-(2-Acyl-1,3-Indandione) Tri Alkyl Ammonium Iodides

1971 ◽  
Vol 26 (9) ◽  
pp. 865-867
Author(s):  
M. K. Bachlaus ◽  
K. L. Menaria ◽  
P. Nath
Keyword(s):  
Free Energy ◽  
Complex Formation ◽  
Stability Constants ◽  
Copper Complex ◽  
Dissociation Constants ◽  
Iron Complex ◽  
Potentiometric Studies ◽  
The Stability ◽  
Alkyl Ammonium

The L-T.M.A.I. and L-T.E.A.I. have been synthesised and their dissociation constants are 7.943 × 10-10 and 1.413 × 10-10 respectively. The potentiometric studies show that these reagents form 1 : 1 complex with copper (II) and iron (II). The stability constants of copper complex and iron complex with L-T.M.A.I. are 5.75 and 6.05 respectively and for L-T.E.A.I., 5.97 and 6.215 respectively. The free energy of complex formation at 25°C are 7841 cals/mole and 8150 cals/mole for Cu(II) -L-T.M.A.I. and Fe(II) -L-T.M.A.I. respectively, whereas the free energy of the Cu(II) -L-T.E.A.I. and Fe(II) -L-T.E.A.I. are 8141 cals/mole and 8375 cals/mole respectively.

Chelating Tendencies of Some N-(2-Acetyl-1,3-Indandione) Trialkyl Ammonium Iodides with Transition Metal Ions

1973 ◽  
Vol 28 (5-6) ◽  
pp. 317-318 ◽  
Author(s):  
M. K. Bachlaus ◽  
K. L. Menaria ◽  
P. Nath
Keyword(s):  
Free Energy ◽  
Complex Formation ◽  
Transition Metal ◽  
Copper Complex ◽  
Dissociation Constants ◽  
Transition Metal Ions ◽  
Iron Complex ◽  
Potentiometric Studies ◽  
Kcal Mole ◽  
The Stability

The ligands T.P.A.I.* and T.B.A.I.** have been synthesised and their dissociation constants are 1.738 · 10-10 and 1.412 · 10-8 respectively. The potentiometric studies show that these reagents form 1 : 1 complex with copper(II) and iron(II). The stability constants of copper complex and iron complex with T.P.A.I. are 6.43 and 6.51 respectively and for T.B.A.I. 4.36 and 4.24 respectively. The free energy of complex formation at 25°C are 8.76 Kcal/mole and 8.87 Kcal/mole for Cu (II)-T.P.A.I. and Fe (II)-T.P.A.I. respectively, whereas the free energy of the Cu (II)-T.B.A.I. and Fe(II)-T.B.A.I. are 5.94 Kcal/mole and 5.78 Kcal/mole respectively.

Using Linear Free Energy Relationship to Predict the Stability Constants of Aqueous Complexes of Metal-Organic Ligands

2004 ◽  
Vol 824 ◽  
Author(s):  
Huifang Xu ◽  
Yifeng Wang
Keyword(s):  
Free Energy ◽  
Metal Complexes ◽  
Stability Constants ◽  
Metal Cation ◽  
Dissociation Constants ◽  
Natural Environments ◽  
Linear Free Energy Relationship ◽  
Free Energies ◽  
Linear Free Energy ◽  
The Stability

AbstractThe Sverjensky-Molling linear free energy relationship was originally developed to correlate the Gibbs free energies of formation of an isostrutural family of solid phases to the thermodynamic properties of aqueous cations. In this paper, we demonstrate that the similar relationship also exists between metal complexes and simple metal cations in aqueous solutions. We extend the Sverjensky-Molling relationship to predict the Gibbs free energies of formation or dissociation constants for a family of metal complexes with a given complexing ligand. The discrepancies between the predicted and experimental data are generally less than 1.5 kcal/mol (or one log unit for stability constants). The use of this linear free energy correlation can significantly enhance our ability to predict the speciation, mobility, and toxicity of heavy metals in natural environments. According the obtained results, Gibbs free energies of formation of cations (δG0f, Mn+) can be used as an indicator for the hardness/softness of a metal cation (acid). The higher negative value of a metal cation, the harder acid it will be. It is logical to postulate that the coefficient a*ML characterizes the softness of a complexing ligand (base).

Study of the properties of pyridine-2-azo-p-phenyltetramethylguanidine as a metal ion complexing agent

1991 ◽  
Vol 69 (8) ◽  
pp. 1238-1244 ◽  
Author(s):  
Kenneth T. Leffek ◽  
Arnold Jarczewski
Keyword(s):  
Complex Formation ◽  
Stability Constants ◽  
Metal Ion ◽  
Nmr Spectra ◽  
Dissociation Constants ◽  
Activation Parameters ◽  
Complexing Agent ◽  
The Stability ◽  
Metal Ligand ◽  
C Nmr

Pyridine-2-azo-p-phenyltetramethylguanidine (PAPT) was synthesized and the properties of this compound examined. The dissociation constants of the conjugate acids in H2O are [Formula: see text] and [Formula: see text] at 25 °C at I = 0.1, and in acetonitrile are [Formula: see text] and [Formula: see text]. The properties of metal–ligand chelates in acetonitrile have been examined and the stability constants for Ni2+, Co2+, and Zn2+ complexes measured. The rates of reaction of PAPT with Ni2+, Co2+, and Zn2+ in acetonitrile have been determined and the activation parameters measured for the complex formation of LNi2+. The stability constants for both complexing centres of PAPT have been calculated. The 13C NMR spectra for PAPT and LNi2+ are quoted. The expected enhancement of the metal ion complexing ability of PAPT due to the strongly electron-releasing nature of the tetramethylguanidinyl group was not found. Key words: metal ion complexes, pyridine-2-azo-p-phenyltetramethylguanidine, stability constants, pKa.

Free-energy patterns in inclusion complexes: the relevance of non-included moieties in the stability constants

2017 ◽  
Vol 19 (7) ◽  
pp. 5209-5221 ◽  
Author(s):  
Tânia F. G. G. Cova ◽  
Sandra C. C. Nunes ◽  
Alberto A. C. C. Pais
Keyword(s):  
Free Energy ◽  
Complex Formation ◽  
Inclusion Complexes ◽  
Stability Constants ◽  
Naphthalene Derivatives ◽  
The Stability

A MD/PMF-based procedure is designed for quantification of the interaction and respective components, guiding complex formation in water between β-CD and several naphthalene derivatives, highlighting the relevance of substituents.

scholarly journals Complex Formation of Nickel(II) and Copper(II) with Barbituric Acid

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Naciye Türkel ◽  
M. Suat Aksoy
Keyword(s):  
Complex Formation ◽  
Stability Constants ◽  
Binary Systems ◽  
Barbituric Acid ◽  
Dissociation Constants ◽  
Individual Species ◽  
Equilibrium Studies ◽  
Ph Titration ◽  
Titration Data ◽  
The Stability

Equilibrium studies have been carried out on complex formation of M2+ ions (M = Ni and Cu) with L = barbituric acid (BA) in aqueous solution at 25.0±0.1°C and with an ionic strength of I=0.10 M (KNO3) in aqueous medium. The basicity of the ligand was also assessed by the determination of the dissociation constants of the ligand. The experimental pH titration data were analyzed with the help of the BEST computer program in order to evaluate the stability constants of the various species formed. The stability constants of the binary systems decrease in the order of Cu(II) > Ni(II). Distribution diagrams for the species were drawn showing the concentrations of individual species as a function of pH by the SPE software program.

scholarly journals Potentiometric and spectrophotometric studies of the complexation of Schiff-base hydrazones containing the pyrimidine moiety

2003 ◽  
Vol 68 (10) ◽  
pp. 729-749 ◽  
Author(s):  
H.S. Seleem ◽  
B.A. El-Shetary ◽  
S.M.E. Khalil ◽  
M. Shebl
Keyword(s):  
Schiff Base ◽  
Ionic Strength ◽  
Thermodynamic Parameters ◽  
Stability Constants ◽  
Elemental Analysis ◽  
Mass Spectra ◽  
Dissociation Constants ◽  
The Stability ◽  
Pyrimidine Moiety ◽  
Metal Ligand

Three Schiff-base hydrazones (ONN ? donors) were prepared by condensation of 2-amino-4-hydrazino-6-methylpyrimidine with 2-hydroxyacetophenone 2-methoxybenzaldehyde and diacetyl to yield 2-OHAHP, 2-OMeBHPand DHP respectively. The structures of these ligands were elucidated by elemental analysis, UV, IR, 1H-NMR and mass spectra. The metal?ligand stability constants of Mn2+, Fe3+,Co2+,Ni2+,Cu2+, Zn2+,Cd2+,UO22+ and Th4+ chelates were determined potentiometrically in two different media (75%(v/v) dioxane?water and ethanol?water) at 283, 293, 303 and 313 K at an ionic strength of 0.05 M (KNO3). The thermodynamic parameters of the 1:1 and 1:2 complexes were evaluated and are discussed. The dissociation constants of 2-OHAHP, 2-OMeBHP and DHPligands and the stability constants of Co2+, Ni2 and Cu2+ with 2-OHAHP were determined spectrophotometrically in 75 % (v/v) dioxane?water.

Equilibrium Studies of Alkyltin(IV) Complexes with D-Glucosamine

1997 ◽  
Vol 62 (7) ◽  
pp. 1023-1028 ◽  
Author(s):  
Mohamed M. Shoukry ◽  
Samir M. El-Medani
Keyword(s):  
Complex Formation ◽  
Stability Constants ◽  
Acid Base ◽  
Complex Formation Equilibria ◽  
Equilibrium Studies ◽  
Formation Equilibria ◽  
Effects Of Temperature ◽  
The Stability

The acid-base and complex-formation equilibria involving glucosamine and its complexes with alkyltin(IV) chlorides have been studied by potentiometric technique. The results prove to a formation of 1 : 1 complex with trialkyltin(IV) and both 1 : 1 and 1 : 2 complexes with dialkyltin(IV) species. The stability constants in water were determined, the effects of temperature (from 15 to 35 °C) and ethanol (up to 88 vol.%) was studied and the speciation of the complexes was resolved.

The affinity of aldehydic compounds to complex formation. Nickel(II) and cobalt(II) complexes with 2-pyridinecarboxaldehyde

1977 ◽  
Vol 55 (14) ◽  
pp. 2613-2619 ◽  
Author(s):  
M. S. El-Ezaby ◽  
M. A. El-Dessouky ◽  
N. M. Shuaib
Keyword(s):  
Complex Formation ◽  
Aqueous Solutions ◽  
Stability Constants ◽  
Metal Ion ◽  
Experimental Conditions ◽  
Complex Species ◽  
Spectrophotometric Methods ◽  
Complex Equilibria ◽  
The Stability ◽  
Hydroxy Groups

The interactions of Ni(II) and Co(II) with 2-pyridinecarboxaldehyde have been investigated in aqueous solutions at μ = 0.10 M (KNO3) at 30 °C. The stability constants of different complex equilibria have been determined using potentiometric methods. Spectrophotometric methods were also used in the case of the nickel(II) – 2-pyridinecarboxaldehyde system. It was concluded that nickel(II) and cobalt(II), analogous to copper(II), enhance hyrdation of 2-pyridinecarboxaldehyde prior to deprotonation of one of the geminal hydroxy groups. Complex species of 1:1 as well as 1:2 metal ion to ligand composition exist under the experimental conditions used.

scholarly journals A Potentiometric Studies of Ternary Complexes of Co(II), Ni(II), Cu(II) and Zn(II) with Ethylenediaamine-N,N,N1,N1-Tetraacetic Acid and Melonic Acid

2018 ◽  
Vol 34 (6) ◽  
pp. 2782-2788
Author(s):  
Sapna Tomar ◽  
Padma Sikarwar
Keyword(s):  
Free Energy ◽  
Ionic Strength ◽  
Complex Formation ◽  
Ternary Complexes ◽  
Potentiometric Studies ◽  
Tetraacetic Acid ◽  
Complex Formation Equilibria ◽  
Formation Equilibria ◽  
Gibb’S Free Energy ◽  
Made In

Potentiometeric investigation on the complex formation equilibria involving Co(II), Ni(II), Cu(II) & Zn(II) with ethylenediaamine-N,N,N1,N1-tetraacetic acid and melonic acid have been made in solution at three different temps viz. (150, 350, 450C). Important thermodynamic parameters namely, change in Gibb’s free energy (DG0), change in enthalpy (DH0) and change in entropy (DS0) and stability constant have been determined potentiometrically at ionic strength of 0.1 M (KNO3).

Substituierte 2-Chloracetessigsäureanilide und ihre Metallchelate / Substituted 2-chloroacetoacetanilides and their metal chelates

1970 ◽  
Vol 25 (12) ◽  
pp. 1386-1388 ◽  
Author(s):  
A. Kettrup ◽  
J. Abshagen
Keyword(s):  
Stability Constants ◽  
Chelating Agents ◽  
Dissociation Constants ◽  
Metal Chelates ◽  
Ph Measurements ◽  
The Stability ◽  
Copper Chelates

The preparation of 2-chloroacetoacetanilides and the preparation of their metal chelates is described.The dissociation constants of the chelating agents and the stability constants of the copper chelates were determined by potentiometric pH-measurements

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