DELTA-G-DEGREES AND T-DELTA-S-DEGREES CHARGE RELATIONSHIPS FOR THE BINDING OF CARBOXYLIC ANIONS BY OPEN-CHAIN POLYAMMONINM CATIONS

Enthalpies of formation have been determined by titration calorimetry for complexes formed by some polycarboxylic anions (citrate, 1,2,3-pro panetricarboxylate, 1,2,3,4-butanetetracarboxylate) with open-chain po lyammonium cations C2(n-1)NnH(6n-2)(n+) (n = 2-6), at 25 degrees C. De lta H degrees values are generally positive and, therefore, these comp lexes are entropically stabilized. Delta G degrees and T Delta S degre es follow a linear trend as a function of polyammonium cation and carb oxylic anion charges. The linear dependence on charges of Delta G degr ees is the same for different systems, whilst that of T Delta S degree s is specific for each system. Delta G degrees and T Delta S degrees c harge relationships are reported.