On the effect of dielectric constant on formation and stability constants of vanadium(V) with leucine in mixed solvent of methanol plus water at 298.15 K

Equilibria in aqueous solutions in the system leucine + VO2+ has been studied by a combination of potentiometric and spectrophotometric methods, in the pH range 3-4.4 with high ligand-to-metal ratios. An equilibrium model, MY, is assumed, where M and Y represent the metal ion and fully dissociated amino acid anion, respectively. The results showed that formation and stability constants of complex system increased with decrease of dielectric constants. Linear relationships were observed when log K-P was plotted vs. 1/D, where K-P and D represent stability and dielectric constants of the system, respectively.