QSAR of distribution coefficients for Pu(NO3)(6)(2-) complexes using molecular mechanics

Computer-aided modeling has been very successful in the design of chelating ligands for the formation of selective metal complexes. We report herein p reliminary efforts to extend the principles developed for ion-specific chel ating ligands to the weaker, more diffuse electrostatic interactions betwee n complex anions and dicationic sites of anion-exchange resins. We present formal- and partial-charge methodologies for determining calculated electro static affinity between plutonium(IV) hexanitrato dianions and free analogu es of dicationic anion-exchange sites. Both approaches correlate well with empirically-determined distribution coefficients for our bifunctional pyrid inium-based resins (0.65 < r(2) < 0.98). This quantitative structure activi ty relationship (QSAR) will be useful in the determination of which structu ral modifications within a select series of bifunctional resins are most li kely to be advantageous. Ultimately, we hope to refine this methodology to allow the a priori determination of ion-exchange behavior for a broad class of materials.