Calorimetric determination of the heats of coordination of competitive ternary mixed-ligand complex compounds. Copper(II)-12-(Z′-hydroxy-3′-methoxy-benzyl)-1,4,7,10-tetraazacyclotridecane-11, 13-dione-α-aminoacids and 5-substituted 1,10-phenanthrolines system

Abstract

The heats of protonation of 12-(2′-hydroxy-3′-methoxy-benzyl)-1,4,7,10-tetra-azacyclotridecane-11, 13-dione (HMTADO) have been determined in aqueous solution at 25 ± 0.1°C and I = 0.1 mol dm-3 KNO3 using a model RD-1 automatic conduction calorimeter. The heats of coordination of binary complex compounds of this ligand with Cu11 and ternary complex compounds of this ligand with Cu11-5-substituted 1,10-phenanthrolines have also been determined under identical conditions. By utilizing the calorimetric data, the heats of coordination of the ternary complex compounds of Cu11-α-aminoacids-HMTADO have been evaluated through “overall calculation”. Some linear enthalpy relationships have been found to exist between the heats of protonation of the ligands and the heats of coordination of the ternary complex compounds. Copyright © 1996 Elsevier Science Ltd