Effects of Size, Basicity and Steric Hindrance on the Solution Stability of Binary and Ternary Complexes of Cadmium(II) with some Amino Acids and Formic Acid : A Polarographic Study

Department of Chemistry, Dr. Hari Singh Gour University, Sagar-470 003 Manuscript rceived 15 July 1992, revised 15 October 1992, accepted 5 November 1992 Polarographic technique was used to determine the values of stability constants (log β) or binary and ternary complexes of Cdll with L-lysine, L-ornithine, L-threonine, L-serine, L-phenylglycine, L-phenylalanine, L·glutamic acid and L-aspartic acid as primary ligands and formic acid as secondary ligand at pH= 8.50 and ionic strength µ = 1.0 M (KNO3) at 25º Cdll forms 1 : 1 : 1, 1: 2 : 1 and 1 : 1 : 2 complexes with selected amino acids and formic acid with stability trend L-lysine < L-ornithine < L-threonine <. L-serine < L-phenylglycine < L-phenylalanine < L-glutamic acid < L- aspartic acid, which is explained on the basis of size, basicity and steric hindrance of these ligand