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 preliminary efforts to extend the principles developed for ion-specific chelating ligands to the weaker, more diffuse electrostatic interactions between complex anions and dicationic sites of anion-exchange resins. We present formal- and partial-charge methodologies for determining calculated electrostatic affinity between plutonium(IV) hexanitrato dianions and free analogues of dicationic anion-exchange sites. Both approaches correlate well with empirically-determined distribution coefficients for our bifunctional pyridinium-based resins (0.65 < r(2) < 0.98). This quantitative structure activity relationship (QSAR) will be useful in the determination of which structural modifications within a select series of bifunctional resins are most likely 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.