Equilibrium Studies of Binary and Ternary Complexes Involving 2-Hydroxy-1- Naphthoic Acid and Amino Acids in Dioxane–Water Mixture (original) (raw)
Related papers
Journal of Chemical & Engineering Data, 2005
The formation of binary and ternary complexes of Co(II), Ni(II), and Cu(II) with bicine [N,N-bis(2hydroxyethyl)glycine] and some selected mono-and dicarboxylic amino acids (glycine, R-alanine, leucine, valine, phenylalanine, asparagine, -alanine, aspartic acid, and glutamic acid) was studied potentiometrically at (298.15 ( 0.1) K and I ) 0.1 mol‚dm -3 (NaNO 3 ) in aqueous solution. The acid-base properties of ligands were investigated and discussed. The formation of the 1:1 binary and 1:1:1 ternary complexes is inferred from the corresponding titration curves. The acidity constants of the ligands were determined and used for determining the stability constants of the complexes formed under the experimental conditions. The ternary complexes are formed in a stepwise mechanism. The stability constants of the binary and ternary systems were evaluated. The stability of the ternary complexes is also discussed in relation to that of the binary complexes of secondary ligands. An evaluation of the effects of ionic strength and temperature of the medium on the stability of the ternary system Cu(II) + bicine + amino acids has been studied. The thermodynamic parameters were calculated and discussed. The stability constant of the above-mentioned ternary system has been investigated in a dioxane-water solution. The complexation behavior of the ternary complexes was ascertained using differential pulse polarography (DPP) and square wave voltammetry.
Monatshefte f�r Chemie / Chemical Monthly, 2004
and Ce III with tricine and for the ternary complexes involving some -amino acids (glycine, -alanine, proline, serine, asparagine, and aspartic acid) were investigated using pH-metric technique. The formation of binary and ternary complexes was inferred from the pH-metric titration curves. It was deduced that tricine acts as a primary ligand in the ternary complexes involving the monocarboxylic amino acids (glycine, -alanine, proline, serine, and asparagine), whereas it behaves as a secondary ligand in the ternary systems containing the dicarboxylic aspartic acid. The ternary complex formation was found to take place in a stepwise manner. The stability constants of the complexes formed in aqueous solutions were determined potentiometrically under the experimental conditions (t ¼ 25 C, I ¼ 0.1 mol dm À3 NaNO 3 ). The order of stability of the ternary complexes in terms of the nature of the amino acids is investigated and discussed. The values of D log K for the ternary complexes have been evaluated and discussed. Evaluation of the effects of ionic strength and temperature of the medium on the stability of the ternary system M II -tricine--alanine (M II ¼ Co II , Ni II , and Cu II ) has been studied. The thermodynamic parameters were calculated and discussed.
Monatshefte Fur Chemie Chemical Monthly, 2004
and Ce III with tricine and for the ternary complexes involving some -amino acids (glycine, -alanine, proline, serine, asparagine, and aspartic acid) were investigated using pH-metric technique. The formation of binary and ternary complexes was inferred from the pH-metric titration curves. It was deduced that tricine acts as a primary ligand in the ternary complexes involving the monocarboxylic amino acids (glycine, -alanine, proline, serine, and asparagine), whereas it behaves as a secondary ligand in the ternary systems containing the dicarboxylic aspartic acid. The ternary complex formation was found to take place in a stepwise manner. The stability constants of the complexes formed in aqueous solutions were determined potentiometrically under the experimental conditions (t ¼ 25 C, I ¼ 0.1 mol dm À3 NaNO 3 ). The order of stability of the ternary complexes in terms of the nature of the amino acids is investigated and discussed. The values of D log K for the ternary complexes have been evaluated and discussed. Evaluation of the effects of ionic strength and temperature of the medium on the stability of the ternary system M II -tricine--alanine (M II ¼ Co II , Ni II , and Cu II ) has been studied. The thermodynamic parameters were calculated and discussed.
Monatshefte f�r Chemie/Chemical Monthly, 2004
metal ions with some selected aliphatic and aromatic hydroxamic acids and some biologically important amino acids or nucleic acid components was investigated using the potentiometric technique at 25 C and I ¼ 0.10 mol dm À3 NaNO 3. The acid-base properties of the ligands were investigated and discussed. The acidity constants of the ligands were determined and used for determining the stability constants of the complexes formed in aqueous medium under the experimental conditions. The ternary complex formation was found to occur in a stepwise manner. The stability constants of these binary and ternary systems were calculated. The order of stability of the ternary complexes in terms of the nature of hydroxamic acid, amino acid, nucleic acid component and metal ions was investigated and discussed as well as the values of D log K and log X for the ternary systems. The concentration distribution of the various complex species in solution was evaluated. In addition, evaluation of the effect of temperature of the medium on the stability of the ternary system M III-benzohydroxamic acid-L-histidine or adenine (M III ¼ Fe III , Al III , and Cr III) has been studied. The thermodynamic parameters were calculated and discussed.
Journal of Solution Chemistry, 2015
Solution equilibria of binary and ternary complexes involving some transition metal (II) ions with N-(2acetamido)iminodiacetic acid as a primary ligand and the biologically relevant ribonucleotides (adenosine-5′-mono- ,-di-, or triphosphate) as secondary ligands were studied using a potentiometric technique. The protonation constants of the ligands were determined and used for determining the stability constants of the complexes formed in aqueous solutions at 25°C and 0.10 mol dm-3 (NaNO 3) ionic strength. The formation of 1:1:1 mixed ligand complexes is inferred from the potentiometric titration curves. The order of stability of the binary or ternary complexes in terms of the nature of both the metal ion and the nucleotide is investigated and discussed. Moreover, the complexation behavior of ternary complexes was ascertained using conductivity measurements.
Journal of Saudi …, 2011
Binary and ternary complexes of the type MY 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 o 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 (∆ log K T) 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.
The binary and ternary complex stability constants between 2,3-dihydroxybenzoic acid (DA) and N-acetylcysteine (Nac) with the divalent metal ions (M) Mn 2? , Co 2? , Ni 2? , Cu 2? and Zn 2? were studied in aqueous solution at 310.15 K and an ionic medium of 0.15 molÁdm -3 NaCl. The complexes' stability constants (log 10 b), refined from the potentiometric data using the Hyperquad2008 program, indicate that the ternary complexes are more stable than the binary complexes. The stability constants were supported by additional computation, refined from the spectrophotometric data using the Hypspec program. The values of the ternary complex stability relative to their binary complex (Dlog 10 K) and the disproportionation constant (log 10 X) indicate that formation of ternary complex species [M(DA)(Nac)] 3is more favorable than that of species formed by two identical ligands, [M(DA) 2 ] 4or [M(Nac) 2 ] 2-. For the investigated M, the stability of complexes follows the trend Cu 2? [ Zn 2? [ Ni 2? [ Co 2? [ Mn 2? .
JCBPSC, 2021
Thermodynamics deprotonations constant ligand's and metal complexes in medicine, agriculture, industries [1-4]. The formation constant of binary and ternary complexes of thiovioluric acid as primary ligands and amino acids as Secondary ligands with Cu(II) and Ni(II) has been examined in 40%(v/v) waterdioxane medium at 25° C and 35° C and at Ionic strength of (0.02) NaClO4 by potentiometric method stability of the complexes decrease and increase in temperature. The primary and secondary ligands simultaneously coordinated to the metal ions to form ternary complexes. The difference in stability constants of binary and ternary complexes. The thermodynamics parameters such as gives free energy change(ΔG), entropy change (ΔS) and enthalpy change (ΔH) accompany the
Chemistry ofProteins which are the most complex substances known to man is one of the great challenges in modern science. In the present work peptides of amino acid were used to study metal-ligand stability constants. Various chelates of metal ions like Al(III), Cr(III), Fe(III), Pt(IV) etc. with various chalcones and amino acids were studied for their stability determination. In the present work complexes of transition metal ions like Cu(II) and Ni(II)with peptide; DL-Alanyl-DL-Alanine were prepared and progress of their formation and metal-ligand stability constants at 0.1M ionic strength were studied potentiometrically. It was found that for Cu(II) the colourlesssolution changed to blue at about pH 5.0 and for Ni(II) at pH 5.25 the colourless solution changed to orange. The stability was studied from Ƞ (ligand number) values and logK values. It is concluded from results that complex of Cu(II) with DL-Alanyl-DL-Alanine is more stable than that for Ni(II).
Formation of binary complexes of Co(II), Ni(II) and Cu(II) with L-DOPA in dioxan-water mixtures
Bulletin of the Chemical Society of Ethiopia, 2011
Complexation of essential metal ions with (S)-2-amino-3-(3,4-dihydroxyphenyl) propanoic acid (dopa) in (0-60% v/v) dioxan-water mixtures has been studied pH-metrically at a temperature of 303 K and an ionic strength of 0.16 M. The existence of different binary species was established from modeling studies using the computer program MINIQUAD75. The best-fit chemical models were selected based on statistical parameters like crystallographic R factor and sum of the squares of residuals in mass-balance equations. The models for binary complex systems contain the chemical species ML, ML2, MLH, ML2H and ML2H2 for Co(II), Ni(II) and Cu(II) in dioxan-water mixtures. The trend in the variation of stability constants with change in the mole fraction of the medium was explained based on electrostatic and non-electrostatic forces. Distribution of the species with pH at different compositions of dioxan-water mixtures was also presented.