CALORIMETRIC DETERMINATION OF THE ENTHALPIES OF COORDINATION OF COMPETITIVE TERNARY MIXED-LIGAND COMPLEX-COMPOUNDS - RAAZACYCLO-TRIDECANE-11,13-DIONE-ALPHA-AMINO-ACIDS AND 5-SUBSTITUTED 1,10-PHENANTHROLINES SYSTEMS

The enthalpies of protonation of 12-(2'-hydroxy-5'-bormo-benzyl)- ,4,7 ,10-tetraazacyclotridecane-11,13-dione(HBTADO) have been determined in aqueous solution at 25.0+/-0.1 degrees C and ionic strength 0.1 mol d m(-3) KNO3 by means of;model RD-1 automatic conduction calorimeter. Th e enthalpies of coordination of the binary complex compounds of this l igand with copper(II) and the ternary complex compounds of this ligand copper(II)-5-substituted 1,10-phenanthrolines have also been determin ed under identical conditions of the ternary complex compounds of the type Cu(II)-alpha-aminoacids-HBTADO have been evaluated through ''over all calculation''. Linear enthalpy relationships, linear enthalpy-entr opy relationships have been found to exist between the enthalpies of f ormation of ternary complex compounds Cu(II)-R'Phen-HRTADO and the ent halpies, entropies of protonation of ligands HRTADO. In addition, line ar enthalpy relationships have been found to exist between the enthalp ies of formation of ternary complex compounds Cu(II)-alpha-aminoacids- HRTADO and the enthalpies of formation of binary complex compounds Cu( II)H(-1)A and linear entropy relationships have been found to exist be tween the entropies of formation of ternary complex compounds Cu(II)-a lpha-aminoacids-HRTADO and the entropies of formation of binary comple x compounds Cu(II)H(-1)A. (C) 1998 Elsevier Science Ltd. All rights re served.