Protonation Equilibria of L‐Aspartic, Citric and Succinic Acids in Anionic Micellar Media

Rao, P. Srinivasa; Srikanth, B.; Rao, V. Samba Siva; Sastry, C. Kamala; Rao, G. Nageswara

doi:10.1155/2009/705976

Cited by 16 publications

(14 citation statements)

References 9 publications

(9 reference statements)

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“…In the pH regions 1.5 -11.5 and 1.9 -7.5, Arg (Lavanya et al, 2004) and Suc (Rao et al, 2009;Srikanth et al, 2009c) exist as LH 2þ 3 and XH 2 , respectively. These protonated ligands interact with the metal ion to form MLXH þ 2 (Equilibrium 1) which may successively be deprotonated to form MLXH and MLX À (Equilibria 2 and 4).…”

Section: Distribution Diagramsmentioning

confidence: 99%

Impact of anionic surfactant on ternary complexes of some metal ions with bio-ligands

Srikanth

Rao

et al. 2012

Chemical Speciation & Bioavailability

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Speciation of Co(II), Ni(II), Cu(II) and Zn(II) with L-arginine as primary ligand (L) and succinic acid as secondary ligand (X) has been studied in various concentrations (0.0 -2.5% wyv) of the anionic surfactant solution maintaining an ionic strength of 0.16 mol dm À 3 (NaNO 3 ) at 303 K. Titrations have been carried out in the presence of different relative concentrations (M: L: X ¼ 1 : 2 : 2, 1 : 2 : 4, 1 : 4 : 2) of metal to L-arginine to succinic acid with sodium hydroxide as titrant. The trend of the variation in the stability constants with changing dielectric constant as well as mole fraction of the medium is explained based on the electrostatic interactions of the side chains of the ligands, charge neutralization, chelate effect, stacking interactions and hydrogen bonding. Distribution diagrams with pH at different compositions of surfactant and structures of plausible ternary complexes are presented.

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Section: Distribution Diagramsmentioning

confidence: 99%

Impact of anionic surfactant on ternary complexes of some metal ions with bio-ligands

Srikanth

Rao

et al. 2012

Chemical Speciation & Bioavailability

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“…The complexation behavior and stability constant of transition metal complex of thiouracil has been reported in previous literature 5 . The stability constant and complexation behavior of Co(II), Zn(II) and Cu(II) complexes with various ligand has also been studied extensively [6][7][8] . Asparagine is one of the 20 most common natural amino acids and synthesized from central metabolic pathway intermediates in human being yet not essential for human diet.…”

Section: Introductionmentioning

confidence: 99%

Formation Constants of Transition Metal Mixed Ligand Ternary Complexes with Biologically Significant Ligands

2016

Chem Sci Trans

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Coordination of ternary complexes of biologically active ligands with transition metals were investigated in aqueous media at 37±1 °C under ionic strength I = 0.1 M NaNO 3. Amino acid asparagine (primary ligand =A) and nucleic acid thiouracil (secondary ligand=B) were applied for complex formation with Cu(II), Ni(II), Zn(II) and Co(II) in aqueous solution (1:1:1). The plausible equilibria have been deduced on the basis of speciation curves obtained through BEST computer program and species are also presented and discussed. The Protonation constant and metal ligand stability constant has been determined through the method suggested by Irving & Rossotti and further refined through BEST computer program. The mixed ligand ternary complexes were occurring simultaneously in most cases generally at high pH with gradually declination of binary complexes of particular metal complexes. The order of mixed ligands ternary system were found A-Cu (

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“…A number of studies have been reported on chemical speciation of α-amino acids in different media (Rao et al, 2009;Sharma et al, 2002). Chemical speciation of a molecule is governed by its structure and solvent effects (Taf, 1983;Hens, 1975).…”

Section: Introductionmentioning

confidence: 99%

Chemical speciation of L-proline complexes of Ca(II), Zn(II) and Mn(II) in acetonitrile-water mixtures

Veeraswami

Bhushanavathi²,

Viplavaprasad

et al. 2013

Chemical Speciation & Bioavailability

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Chemical speciation of binary complexes of Ca(II), Zn(II) and Mn(II) with L-proline is investigated pH-metrically in acetonitrile-water mixtures. The stability constants are calculated using the computer program MINIQUAD75. The best-fit chemical models are selected based on statistical parameters and residual analysis. The models for the binary species contained ML + , MLH 2+ and ML 2 H + for Ca(II), Zn(II) and Mn(II). The trend in variation of stability constants with change in the dielectric constant of the medium is explained on the basis of structure forming nature of acetonitrile. Distribution of the species with pH at different variations (0.0-60.0% v/v) in acetonitrile-water mixtures is also presented.

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Protonation Equilibria of L‐Aspartic, Citric and Succinic Acids in Anionic Micellar Media

Cited by 16 publications

References 9 publications

Impact of anionic surfactant on ternary complexes of some metal ions with bio-ligands

Impact of anionic surfactant on ternary complexes of some metal ions with bio-ligands

Formation Constants of Transition Metal Mixed Ligand Ternary Complexes with Biologically Significant Ligands

Chemical speciation of L-proline complexes of Ca(II), Zn(II) and Mn(II) in acetonitrile-water mixtures

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