Abstract
The knowledge of water exchange reaction mechanism in aqueous solutions of Gd3+ polyaminocarboxylates is important for the understanding of the relatively slow water exchange rates measured for these complexes. Variable ressure measurements show a change of mechanism from associatively activated on [Gd(H2O)8]3+ and [Gd(PDTA)(H2O2)2]− to probably limiting dissociative on the MRI contrast agents [Gd(DOTA)(H2O)]−, [Gd(DTPA)(H2O)]2− and [Gd(DTPA-BMA)(H2O)].