CALORIMETRIC DETERMINATION OF THE HEATS OF FORMATION OF COMPETITIVE TERNARY MIXED-LIGAND COMPLEX-COMPOUNDS - ,10-TETRAAZACYCLOTRIDECANE-11,13-DIONE-ALPHA-AMINO ACIDS AND 5-SUBSTITUTED PHENANTHROLINES SYSTEMS

The heats of protonation of zyl)-1,4,7,10-tetraazazacyclotridecane-11, 13-dione (HTADO) have been determined in aqueous solution at 25 +/- 0. 1 degrees C and I = 0.1 mol dm(-3) KNO3 by conduction calorimetry. The heats of formation of the binary complex compound of this ligand with Cu(II) and the ternary complex compounds of this ligand with Cu(II)-5 -substituted phenanthrolines have also been determined under identical conditions. By utilizing the calorimetric data, the heats of formatio n of the ternary complex compounds Cu(II)-alpha- amino acids-HTADO hav e been evaluated through ''overall calculation''. Some linear enthalpy relationships have been found between the heats of protonation of the ligands and the heats of formation of the ternary complex compounds.