Thermodynamics of protonation of polymeric bases whose repeating units behave independently

The protonation of some poly(amido amine)s has been studied in aqueous solution by potentiometric, calorimetric, and 13C‐NMR methods. Only “apparent” constants were usually found in polymeric acids and bases; on the other hand, “sharp” basicity constants could be determined for the poly(amido amine)s studied. The log K values determined from 13C‐NMR shifts versus pH agree well with those determined by potentiometric titrations. Also, the protonation enthalpies do not depend on the dissociation degree of polymeric bases, and this is a further proof of the peculiarity of this class of polymers. The trends of ΔH's and the conformations of polymers in solution are analyzed on the basis of theoretical computations.