Speciation of Cobalt(II) complexes with succinic acid and L-glutamine in Tetra Butyl Ammonium Bromide – water mixtures

Abstract

Speciation of cobalt(II) complexes with L-glutamine (Gln) and succinic acid (Suc) in varying concentrations (0.0-3.0%, w/v) of TBAB-water mixtures with pH-meter has been made at an ionic strength of 0.16 mol dm-3 and temperature 303 K using a Control Dynamics-APX 175E/C pH meter. Various models for the species of these ligards are refined by using the computer programs SCPHD and MINIQUAD75. The active forms of the Cobalt(II) are ML, ML2 and MLH for succinic acid and ML and ML2H for L-glutamine. The trend in the variation of protonation constants with dielectric constant is explained on the basis of electrostatic and non-electrostatic forces. The species distribution with pH at different solvent composition and the plausible equilibria for the formation of the species are also presented.

Keywords

• Complex Equilibria
• Speciation
• L-Glutamine
• Succinic Acid
• Cobalt
• Tbab