Linear enthalpy relationships between the heats of formation of coordination compounds and the heats of protonation of the ligands: The copper(II)- N-( meta-substituted phenyl)-iminodiacetic acid-α-amino acid competitive ternary system

Abstract

The heats of formation of the ternary complex compounds of Cu II- N-( meta-substituted phenyl)iminodiacetic acid-α-amino acid ( m-RPhIDA, N-( meta-substituted phenyl)imin-odiacetic acid, R  CH 3, H, CH 3O or Cl; AA, α-amino acid, AA  proline, α-aminoisobutyric acid, isoleucine, glycine, valine or serine) have been determined in aqueous solution at 25.0 ± 0.2°C and I = 0.1 mol dm −3 (KNO 3) by means of an automatic conduction calorimeter, model RD-1. The results show the existence of linear enthalpy relationships between the heats of formation of these ternary compounds and the heats of protonation of the m-RPhIDA ligands.