Stability constants of mixed ligand complexes of lead(II) with 1-(aminomethyl) cyclohexane acetic acid and α-amino acids

Thanavelan, R.; Ramalingam, G.; Manikandan, G.; Thanikachalam, V.

doi:10.1016/j.jscs.2011.06.016

Cited by 16 publications

(9 citation statements)

References 28 publications

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“…The properties of the studied central metal ions and the stability constants of their complexes were discussed in an effort to give information about the nature of chemical bonding in complexes and make possible the calculation of the stability constants. The stability constants of 1:2 ratio (metal-ligand) complexes are lower than those of the corresponding 1:1 ratio compounds, as expected from statistical considerations [28]. The formation constants of the obtained complexes of HL are arranged as follows: La(III) > Fe(III) > Cu(II) > Co(II) > Ni(II) > Mn(II).…”

Section: Acidity Constants Of the Free Ligandsupporting

confidence: 53%

Potentiometric and Theoretical Studies of 2-((4-Morpholinobenzylidene)amino)phenol With Some Transition Elements

2018

Assiut University Journal of Multidisciplinary Scientific Resea

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The stability constants of Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and La(III) metal ions with 2-((4-morpholinobenzylidene)amino)phenol (HL) were determined in 25 % (v/v) ethanol-water medium at 25 o C (I = 1 M NaClO 4 ). The calculations of the metal-ligand stability constants were obtained by Calvin-Bjerrum pH-metric method using the Miniquad-75 computer program. The dissociation constant (pK a ) value of monoprotic ligand HL was found as 10.36. The order of the formation constant values (log K i ) of metal ion complexes with HL increases in the order La(III) > Fe(III) > Cu(II) > Co(II) > Ni(II) > Mn(II). Optimization of the geometries of the HL metal complexes was done with the density functional theory method (DFT) using the Gaussian 09 program package as DFT methods.

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Section: Acidity Constants Of the Free Ligandsupporting

confidence: 53%

Potentiometric and Theoretical Studies of 2-((4-Morpholinobenzylidene)amino)phenol With Some Transition Elements

2018

Assiut University Journal of Multidisciplinary Scientific Resea

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“…They are very important in many fields such as environmental studies, medicinal, analytical and industrial chemistry [1][2][3][4]. Therefore complexation reactions of metal ions with different ligands have been widely studied [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Formation constants and thermodynamic parameters of bivalent Co, Ni, Cu and Zn complexes with Schiff base ligand: Experimental and DFT calculations

Esmaielzadeh¹,

Mashhadiagha²

2017

Bull. Chem. Soc. Eth.

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ABSTRACT. Formation constant (Kf) values of Schiff base ligand, L = methyl-2-{[1-methyl-2-(aceton)ethylidynenitrilo]ethyl}amino-1-cyclopentenedithiocarboxylate, with Co(II), Ni(II), Cu(II) and Zn(II) ions has been determined spectrophotometrically for 1:1 complex formation at constant ionic strength 0.01 M (NaClO4), and at various temperatures in DMF solvent. Thermodynamic studies of the complexes have been carried out and their stability were found in the order CoL > CuL > NiL > ZnL. The enthalpy, entropy and Gibbs free energy changes of the complexation reaction have been evaluated from the temperature dependence of the formation constant. Our experimental results revealed that the complexation process is spontaneous, exothermic and entropically unfavorable. Also, B3LYP/(LANL2DZ and ‫)٭٭‪6-311G‬‬ level density functional theory is applied on the structure and stability of Schiff base ligand and their complexes. HOMO-LUMO and binding energies were calculated to obtained stability of the complexes. The theoretical results are compared with experimental data.

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“…The less value of dielectric constant is the reason for the lowering in solvation of the metal ions in DMSO, resulting in higher attraction force which in turn, approaches the ligand to viable coordination of metal ion resulting in enhanced stability of the complex in DMSO 13 , hence the electrostatic forces of attraction between two oppositely charged species were significant, and therefore the stability of the complexes are more in the aqueous-organic solvent mixtures than in purely aqueous medium. This could be attributed to the hydrogen bonding ability of water and the solvating tendency of DMSO 14 .…”

Section: Discussionmentioning

confidence: 99%

Potentiometric Studies of Binary Complexes of Transition Metal Ions with Lauric Acid

2018

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The potentials of binary complexes of the Lauric acid ligand with various biologically vital divalent metal ions such as Mn(II), Co(II), Ni(II), Cu(II)and Zn(II) have been studied in 50% DMSO-water mixture at constant ionic strength by Bjerrum method. Hydrogen ion concentrations were measured and the formation of binary complexes was inferred from the corresponding potentiometric pH-titration curves. The metal to ligand mole ratio was maintained at 1:5 to facilitate the maximum number of ligands to the metal ion. The dissociation constant has been determined by the half-integral method and pointwise method and were found in good agreement with each other. The Metal-Lauric acid stability constants have been calculated and compared with the results.

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Stability constants of mixed ligand complexes of lead(II) with 1-(aminomethyl) cyclohexane acetic acid and α-amino acids

Cited by 16 publications

References 28 publications

Potentiometric and Theoretical Studies of 2-((4-Morpholinobenzylidene)amino)phenol With Some Transition Elements

Potentiometric and Theoretical Studies of 2-((4-Morpholinobenzylidene)amino)phenol With Some Transition Elements

Formation constants and thermodynamic parameters of bivalent Co, Ni, Cu and Zn complexes with Schiff base ligand: Experimental and DFT calculations

Potentiometric Studies of Binary Complexes of Transition Metal Ions with Lauric Acid

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