CALORIMETRIC DETERMINATION OF THE HEATS OF COORDINATION OF COMPETITIVE TERNARY MIXED-LIGAND COMPLEX-COMPOUNDS - ,10-TETRAAZACYCLOTRIDECANE-11,13-DIONE-ALPHA-AMINO ACIDS AND COPPER(II)-5-SUBSTITUTED 1,10-PHENANTHROLINE SYSTEMS

The heats of protonation of 1,4,7,10-tetraazacyclotridecane-11,13-dion e (TADO) have been determined in aqueous solution at 25.0+/-0.1 degree s C and ionic strength 0.1 mol dm(-3) KNO3. The heats of coordination of the binary complex compounds of this ligand with copper(II) and the ternary complex compounds of this ligand with copper(II)-5-substitute d 1,10-phenanthrolines have also been determined under identical condi tions. By utilizing the calorimetric data, the heats of coordination o f the ternary complex compounds of the type copper(II)-alpha-amino aci ds-TADO have been evaluated through ''overall calculation''. Some line ar enthalpy relationships have been found to exist between heats of pr otonation of the ligands and heats of coordination of ternary complex compounds.