A Study of Stability Constants of [Zn – L-Amino Acidate – Vitamin-PP] Systems

The polarographic technique was used in formation of zinc (II) mixed ligand complexes of amino acids viz. glycine, α-alanine, L-leucine, L-valine, L-asparagine L-glutamine used as primary ligands and vitamin-PP (nicotinamide) as the secondary ligand at pH = 7.30 ± 0.01, μ = 1.0 M NaClO4 at 25℃ and 35℃. The complexes with metal to ligands ratio 1:1: 1, 1: 1:2 and 1: 2: 1 have been reported. The stability constants varied from 1.91 to 11.50. The kinetic parameters and thermodynamic parameters were also also determined. The values of standard rate constant (k) were of the order of 10-3cm sec-1 confirmed the quasireversible nature of electrode processes. The thermodynamic parameters reveal that complexes were lesser stable at high temperature.