Contribution of Molecular Dynamics in pNMR for the Structural Determination of AnV and AnVI Complexes in Solution.

Abstract

In this study, we propose to use classical molecular dynamics (MD) coupled with 1H NMR spectroscopy to study the conformations of different actinyl AnVI (An = U, Np, and Pu) and AnV (An = Np) complexes with tetra-ethyl dyglicolamide (TEDGA) ligands in order to have a better representation of such complexes in solution. Molecular dynamics simulations showed its effectiveness in interpreting the experiments by the calculation of geometric factors needed for the determination of magnetic properties of these complexes. We demonstrated that different conformations of the AnV and AnVI complexes with TEDGA exist in solution with different coordination modes, which is experimentally confirmed by 1H NMR and EXAFS spectroscopies. Furthermore, MD simulations provide additional insights into the structures of complexes in solution since conformations with fast exchanges, which are not accessible from NMR experiments, have been observed by MD simulations.