scholarly journals Effect of micelles on the chemical speciation of binary complexes of Co(II), Nii(II), Cu(II) and Zn(II) with succinic acid

2009 ◽  
Vol 74 (7) ◽  
pp. 745-754
Author(s):  
Bathula Srikanth ◽  
Srinivasa Rao ◽  
Siva Rao ◽  
Kamala Sastry ◽  
Nageswara Rao
Keyword(s):  
Ionic Strength ◽  
Computer Program ◽  
Succinic Acid ◽  
Mole Fraction ◽  
Chemical Speciation ◽  
Ionic Surfactants ◽  
Binary Complex ◽  
Complex Species ◽  
Binary Complexes ◽  
Modelling Studies

Speciation of Co(II), Ni(II), Cu(II) and Zn(II) complexes with succinic acid in the presence of anionic, cationic and non-ionic surfactants at an ionic strength of 0.16 mol dm-3 and temperature 303 K were investigated pH metrically. The existence of different binary complex species was established from modelling studies using the computer program MINIQUAD75. The decreased stability of the complexes with increasing micellar content was explained by electrostatic forces. The influence of the micelles on the chemical speciation is discussed based on the mole fraction of the medium. Distribution diagrams of various species of the complexes in relation to pH are presented.

Complexes of Cu(II) with D-aldonic and D-alduronic acids in aqueous solution

1992 ◽  
Vol 70 (7) ◽  
pp. 2053-2057 ◽  
Author(s):  
Graciela M. Escandar ◽  
Luis F. Sala
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Computer Program ◽  
Quantitative Study ◽  
Hydrogen Ion ◽  
Complex Species ◽  
Ion Concentrations ◽  
Aldonic Acid ◽  
Potentiometric Measurements ◽  
Equilibrium Data

A quantitative study of the equilibria involved in the interaction of Cu(II) ion with D-glucoheptonic, D-gluconic, D-galactonic, D-ribonic, D-glucuronic, and D-galacturonic acids in aqueous medium has been carried out by means of potentiometric measurements of hydrogen ion concentrations at a constant temperature of 20 °C and an ionic strength of 0.10 (NaNO3). The equilibrium data were processed with the FORTRAN computer program BEST. It was found that Cu(II) interacts with D-aldonic acids to form 1:1, 2:2, and 1:2 (M/L) complexes. The copper(II) complexes with D-galacturonic and D-glucuronic acids are considerably weaker than those of D-aldonic acid. Possible structures of the complex species formed are discussed.

scholarly journals Protonation Equilibria of L-Aspartic, Citric and Succinic Acids in Anionic Micellar Media

2009 ◽  
Vol 6 (2) ◽  
pp. 561-568 ◽  
Author(s):  
P. Srinivasa Rao ◽  
B. Srikanth ◽  
V. Samba Siva Rao ◽  
C. Kamala Sastry ◽  
G. Nageswara Rao
Keyword(s):  
Citric Acid ◽  
Ionic Strength ◽  
Computer Program ◽  
Succinic Acid ◽  
Protonation Constants ◽  
Micellar Media ◽  
Statistical Parameters ◽  
Protonation Equilibria ◽  
The Impact ◽  
Best Fit

The impact of sodium lauryl sulphate (SLS) on the protonation equilibria ofL-aspartic acid, citric acid and succinic acid has been studied in various concentrations (0.5-2.5%w/v) of SLS solution maintaining an ionic strength of 0.16 mol dm-3at 303 K. The protonation constants have been calculated with the computer program MINIQUAD75 and the best fit models have been calculated based on statistical parameters. The trend of log values of step-wise protonation constants with mole fraction of the medium has been explained based on electrostatic and non-electrostatic forces operating on the protonation equilibria. The effects of errors on the protonation constants have also been presented.

scholarly journals Computer augmented modelling studies of Pb(II), Cd(II), Hg(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes of L-glutamic acid in 1,2-propanediol-water mixtures

2008 ◽  
Vol 73 (12) ◽  
pp. 1169-1180 ◽  
Author(s):  
Rao Vegi ◽  
Latha Muddapu ◽  
Rao Tirukkuvalluri ◽  
Rao Gollapalli
Keyword(s):  
Dielectric Constant ◽  
Ionic Strength ◽  
Glutamic Acid ◽  
Stability Constants ◽  
Chemical Speciation ◽  
Systematic Errors ◽  
Specific Interactions ◽  
Solvent Water ◽  
Modelling Studies ◽  
The Stability

Chemical speciation of Pb(II), Cd(II), Hg(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes of L-glutamic acid was studied at 303 K in 0-60 vol. % 1,2-propanediol-water mixtures, whereby the ionic strength was maintained at 0.16 mol dm-3. The active forms of the ligand are + LH3, LH2 and LH-. The predominant detected species were ML, ML2, MLH, ML2H and ML2H2. The trend of the variation in the stability constants with changing dielectric constant of the medium is explained based on the cation stabilizing nature of the co-solvents, specific solvent-water interactions, charge dispersion and specific interactions of the co-solvent with the solute. The effect of systematic errors in the concentrations of the substances on the stability constants is in the order alkali > > acid > ligand > metal. The bioavailability and transportation of metals are explained based on distribution diagrams and stability constants.

Chemical speciation of binary complexes of L-valine with Co(II), Ni(II) and Cu(II) in propylene glycol–water mixtures

2013 ◽  
Vol 25 (1) ◽  
pp. 57-62
Author(s):  
Peketi Bhushanavathi ◽  
Boddu Veeraswami ◽  
Uppuleti Viplavaprasad ◽  
Gollapalli Nageswara Rao
Keyword(s):  
Propylene Glycol ◽  
Chemical Speciation ◽  
Binary Complexes

Determination of the complexation properties of a crosslinked poly(acrylic acid) gel with copper(II), nickel(II), and lead(II) in dilute aqueous solution

2001 ◽  
Vol 79 (4) ◽  
pp. 370-376 ◽  
Author(s):  
Catherine Morlay ◽  
Yolande Mouginot ◽  
Monique Cromer ◽  
Olivier Vittori
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Acrylic Acid ◽  
Metal Ion ◽  
Conditional Stability ◽  
Binding Properties ◽  
Complex Species ◽  
Complexing Capacity ◽  
Dilute Aqueous Solution ◽  
Poly Acrylic Acid

The possible removal of copper(II), nickel(II), or lead(II) by an insoluble crosslinked poly(acrylic acid) was investigated in dilute aqueous solution. The binding properties of the polymer were examined at pH = 6.0 or 4.0 with an ionic strength of the medium µ = 0.1 or 1.0 M (NaNO3) using differential pulse polarography as an investigation means. The highest complexing capacity of the polyacid was obtained with lead(II) at pH = 6.0 with µ = 0.1 M, 4.8 mmol Pb(II)/g polymer. The conditional stability constants of the complex species formed were determined using the method proposed by Ruzic assuming that only the 1:1 complex species was formed; for lead(II) at pH = 6.0 and µ = 0.1 M, log K' = 5.3 ± 0.2. It appeared that the binding properties of the polymer increased, depending on the metal ion, in the following order: Ni(II) < Cu(II) < Pb(II). The complexing capacity and log K' values decreased with the pH or with an increase of the ionic strength. These results were in agreement with the conclusions of our previous studies of the hydrosoluble linear analogues. Finally, with the insoluble polymer, the log K' values were comparable to those previously obtained with the linear analogue whereas the complexing capacity values expressed in mmol g-1 were slightly lower.Key words: insoluble crosslinked poly(acrylic acid), copper(II), nickel(II), and lead(II) complexation.

scholarly journals NADP-Dependent Aldehyde Dehydrogenase from Archaeon Pyrobaculum sp.1860: Structural and Functional Features

Archaea ◽  
2016 ◽  
Vol 2016 ◽  
pp. 1-14
Author(s):  
Ekaterina Yu. Bezsudnova ◽  
Tatiana E. Petrova ◽  
Natalia V. Artemova ◽  
Konstantin M. Boyko ◽  
Ivan G. Shabalin ◽  
...  
Keyword(s):  
Aldehyde Dehydrogenase ◽  
Active Sites ◽  
Ternary Complex ◽  
Binary Complex ◽  
Relay Systems ◽  
Binary Complexes ◽  
Proton Relay ◽  
Functional Features

We present the functional and structural characterization of the first archaeal thermostable NADP-dependent aldehyde dehydrogenase AlDHPyr1147. In vitro, AlDHPyr1147 catalyzes the irreversible oxidation of short aliphatic aldehydes at 60–85°С, and the affinity of AlDHPyr1147 to the NADP+ at 60°С is comparable to that for mesophilic analogues at 25°С. We determined the structures of the apo form of AlDHPyr1147 (3.04 Å resolution), three binary complexes with the coenzyme (1.90, 2.06, and 2.19 Å), and the ternary complex with the coenzyme and isobutyraldehyde as a substrate (2.66 Å). The nicotinamide moiety of the coenzyme is disordered in two binary complexes, while it is ordered in the ternary complex, as well as in the binary complex obtained after additional soaking with the substrate. AlDHPyr1147 structures demonstrate the strengthening of the dimeric contact (as compared with the analogues) and the concerted conformational flexibility of catalytic Cys287 and Glu253, as well as Leu254 and the nicotinamide moiety of the coenzyme. A comparison of the active sites of AlDHPyr1147 and dehydrogenases characterized earlier suggests that proton relay systems, which were previously proposed for dehydrogenases of this family, are blocked in AlDHPyr1147, and the proton release in the latter can occur through the substrate channel.

Thermodynamics of complex formation in binary liquid mixtures: application to systems containing acetonitrile

1977 ◽  
Vol 55 (16) ◽  
pp. 2980-2992 ◽  
Author(s):  
John W. Lorimer ◽  
David E. Jones
Keyword(s):  
Binary Systems ◽  
Liquid Mixtures ◽  
Binary Liquid Mixtures ◽  
Binary Complex ◽  
Binary Liquid ◽  
Binary Complexes ◽  
Excess Gibbs Energies ◽  
Thermodynamics Of Complex Formation ◽  
Volumes Of Mixing ◽  
Self Association

Equations for enthalpies and volumes of mixing are derived from thermodynamic association theory for complex binary liquid mixtures containing self-associating species and binary complexes. The various species can interact through general non-specific interactions of the simple mixture type.The equations, along with equations for the excess Gibbs energy, are applied to experimental data on excess Gibbs energies, heats, and volumes of mixing for the three binary systems formed from acetonitrile, carbon tetrachloride, and chloroform. The data require a theoretical model that involves two types of self-association of acetonitrile, one type of self-association of chloroform and formation of a binary complex CH3CN•2CHCl3. Thermodynamic parameters for the various types of association and interaction are derived by constrained least-squares methods, and provide a unified picture of the thermodynamic properties of these mixtures.

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.

Sign in / Sign up

Export Citation Format

Share Document