Linear enthalpy relationships between heats of formation of complex compounds and heats of protonation of ligands. Copper(II)- N-( para-substituted phenyl)iminodiacetic acid-α-amino acids ternary system and copper(II)- N-( para-substituted phenyl)iminoacetic acids binary system

Abstract

The heats of protonation of N-( para-substituted phenyl)iminodiacetic acids (A, p-RPhIDA: RCH 3O, CH 3, H, Cl) and the heats of formation of Cu(II)- p-RPhIDA binary complex compounds and of Cu(II)- p-RPhIDA-α-amino acids (B, AA: L-proline, L-isoleucine, L-valine, L-serine, glycine and α- aminoisobutyric acid) competitive ternary complex compounds have been determined at 25.0 ± 0.2 °C, and I = 0.1 mol dm −3 (KNO 3) by means of a model RD-1 automatic conduction calorimeter. In the meantime the entropy of protonation of the ligand A and the entropy of formation of the binary complex compounds Cu(II)- p-RPhIDA-AA have been calculated. The results showed the existence of linear enthalpy relationships between the heats of formation of these ternary complex compounds and the binary complex compounds and the heats of protonation of the ligands p-RPhIDA and the existence of linear entropy relationships between the entropy of formation of binary complex compounds, Cu(II)- p-RPhIDA and the entropy of protonation of ligands, p-RPhIDA.