Estimation of Stability Constants of Copper(II) Chelates with N-alkylated Amino Acids using Topological Indices

摘要: Protonation (pK(1) and pK(2)) copper(II) binding stability constants (log beta(110) log beta(120)) of glycine five N-alkylated glycines (methyl, dimethyl, diethyl, tert-butyl tert-butylmethyl) were determined by potentiometric titration. These the eight glycinates, measured previously, correlated with four topological indices (Wiener index, W, first-, second- third-order valence-connectivity indices, (1)chi(v), (2)chi(v) (3)chi(v)) calculated for ligand. The first protonation (ascribed to dissociation COOH group) do not correlate any chosen (r(2) < 0.3), but significant correlation was obtained pK2 (dissociation amino r(2) values up 0.920. "Corrected (obtained subtracting pK(2) value) yielded a generally better fit than uncorrected ones. Our are (max. = 0.993) previously 0.836). From regression analysis it is possible predict pK(2), beta(120) an error less 0.1, 0.3 units, respectively.