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

Abstract

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.

Stability constants of adducts of succinate copper(II) complexes with β‐cyclodextrin determined by capillary electrophoresis

“…Copper is a biogenic metal that forms complexes with different ligands, among which are ions of succinic acid ; some copper complexes are being studied as agents for the treatment of cancer . The adducts of succinate copper(II) complexes and β‐CD had not been studied before.…”

Composition and stability constants of copper(II) complexes with succinic acid determined by capillary electrophoresis

“…Copper is a biogenic metal that forms complexes with many ligands among which are ions of succinic acid (H 2 L) [1][2][3][4][5][6][7][8][9][10][11]. In a number of studies, the only CuL 0 and sometimes CuHL + complexes are mentioned for the copper(II) -succinic acid system [12][13][14][15].…”