First‐principles study on the plutonium ions interaction with diamide molecules in acid solutions. Issue 16 (9th June 2021)

• Record Type: Journal Article
• Authors: Ryzhkov, Mikhail V.; Enyashin, Andrei N.; Delley, Bernard
• Is Part Of: International journal of quantum chemistry. Volume 121:Issue 16(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-06-09
• Subjects: explicit modeling of solutions -- relativistic methods -- stability of plutonium complexes; Quantum chemistry -- Periodicals; 541.28
• DOI: 10.1002/qua.26681
• Languages: English
• ISSNs: 0020-7608

Abstract

Abstract: Theoretical study of the formation of Pu Z+ (Z = 3, 4, 5, 6) complexes with the two types of diamide molecules C8 N2 H10 O2 (CH3 )2 (dimethylbicyclicdiamide—DMDA) with bicyclic structure and C3 N2 H2 O2 (CH3 )4 (tetramethylmalonamide—TMMA) with acyclic structure was carried out using ab initio DFT based DMol 3 and relativistic discrete variational methods. The results of gas phase modeling showed that the appropriate positions of the oxygen atoms in DMDA in comparison with TMMA cannot explain the considerable difference in sorption affinity of these molecules. For the modeling of solutions, the implicit (COSMO) and explicit methods were used. In the latter approach, we included 40 water molecules, 16NO3 − or 16Cl − and 16H + ions into the systems under investigation. The obtained results showed the principle role of solution in the weakening of actinide bonding with TMMA and DMDA molecules due to interaction with H2 O and NO3 − or Cl − ions. Abstract : The gas phase modeling as well as the implicit simulation of the role of the solvent do not explain the considerable difference in sorption affinity of bicyclic diamide molecule in comparison with zig‐zag counterpart. Only the explicit inclusion of several water molecules and acid ions into the system under investigation allows the understanding of the pivotal role of solution in the weakening of plutonium bonding with the two types of diamide molecules.