Estimation of Stability Constants of Cadmium(II) bis-Complexes with Amino Acids by Model Based on 3χ v Connectivity Index

Linear model for estimation of the second, K2, and overall,β2, stability constant of cadmium(II) binary and ternary biscomplexes with five aliphatic α-amino acids based on valence connectivity index of the 3rd order (3χv) was developed. Set of amino acids included glycine, alanine, 2-aminobutanoic, 2-aminopentanoic (norvaline) and 2-aminohexanoic acid (norleucine), which by bonding to the cadmium(II) gave 25 K2 and 15 β2 values. For estimation of log β2, the model gave r = 0.940, and the S.E.cv = 0.10, and for the two subsets of log K2 constants the model yielded r = 0.936 and 0.842, and S.E.cv = 0.09. The complex CdGG was excluded from all regressions.