the solubility of co2 in the primary, secondary, tertiary and sterically hindered amine aqueous solutions at various conditions was studied. in the present work, the modified kent-eisenberg (m-ke), the extended debye-hückel (e-dh) and the pitzer models were employed to study the solubility of co2 in amine aqueous solutions. two explicit equations are presented to evaluate the concentration of h...

A novel macrocyclic DO3A derivative containing a linear diamine pendant arm, H3do3aNN, was prepared and its protonation and complexation properties were studied by means of potentiometry. It determined ligand consecutive protonation constants log K(An) = 12.62, 10.28, 9.67, 8.30, 3.30 and 1.58 and stability constants of selected lanthanide (Eu(iii), Yb(iii)) complexes log K(EuL) = 23.16 and log...

the stability constants and complexation reaction between l-glutamine, l-arginine andglycine with zn (ii) , co (ii) and ni (ii) were studied potentiometrically in aqueous solution at25° c and μ=0.1 m kno3. the overall stability constants log β´s of all species are obtained bycomputer refinement of ph-volume data using best computer program. several models weretested and the lowest δfit, the bes...

A new tris-(2-aminoethyl)amine (TREN) capped tripodal Schiff base ligand has been developed by mimicking structural features of a natural siderophore, Bacillibactin, by substituting the catechol units with salicylaldehyde and employing amino acid as spacer. Synthesis of the ligand N-[2-[bis[2-[[2-[(2-hydroxyphenyl)methylamino]acetyl] amino]ethyl]amino]ethyl]-2-[(2-hydroxyphenyl)methylamino]...

equilibria of the reaction of molybdenum(vi) with l-aspartic acid (asp) and l- glutamic acid(glu) have been studied by spectrophotometric measurements in mixed solvent systems at an ionicstrength of 0.2 mol/dm3 sodium perchlorate, employed (15, 20, 25, 30± 0.1°c) at ph ranges of 3.2to 5.5 with a high ratio of ligand to metal. the stability constants of the complexes and theresulting free energy...

The solute-solvent interactions of L-glutamic acid and L-methionine have been studied in 0–60% V/V 1,2-propanediolwater media using the pH-metric method. The protonation constants have been calculated with the computer program MINIQUAD75. Selection of the best fit chemical model of the acid-base equilibria is based on standard deviation in protonation constants and residual analysis using cryst...

the protonation constant values of salicylic and 5-nitrosalicylic acid werestudied by a combinationof spectrophotometric and potentiometric methods at 25 °c in wide range of ionic strength. the ionicstrength of solutions was kept constant by sodium perchlorate as background electrolyte at 0.10 to 3.0 moldm-3. potentiometer was calibrated according to gran method at each of ionic strength. the p...

The solute-solvent interactions of L-Cysteine and L-Methionine have been studied pH metrically in various concentrations (0.060.0% v/v) 1, 4-Dioxane-water mixture maintaining an ionic strength of 0.16 mol L-1 at ambient conditions. The protonation constants have been calculated with the computer program MINIQUAD75 and the best fit chemical models are selected based on statistical parameters. Li...

The synthesis of a new linear bis-tetraamine ligand L1, based on two 1,4,8,11-tetraazaundecane units grafted at the 2 and 6 positions of a pyridinyl linker substituted by an anthracenyl fluorophore in the para position, is described and anion complexation studies of L1 with anionic substrates are reported. The protonation pattern and the study of the binding properties of L1 in an aqueous mediu...

Nicotine (NIC) is an oxygenic alkaloid compound exists in two forms R and S, and consists of a pyridine ring, substituted at the 3-position with an N-methyl-pyrrolidine ring. Nicotine is extracted mostly from the Nicotiana tabacum plant, and although it was made in the roots and accumulates in smaller amounts in leaves of edible plants of the nightshade family called “Solanaceae’’ such as tomat...