Prediction of Binding Stability of Pu(IV) and PuO2(VI) by Nitrogen Tridentate Ligands in Aqueous Solution.

Keunhong Jeong,Sungchul Bae,Seung Min Woo,Hye Jin Jeong

doi:10.3390/ijms21082791

Abstract

Plutonium has potential applications in energy production in well-controlled nuclear reactors. Since nuclear power plants have great merit as environmentally friendly energy sources with a recyclable system, a recycling system for extracting Pu from spent fuels using suitable extractants has been proposed. Pu leakage is a potential environmental hazard, hence the need for chemical sensor development. Both extractants and chemical sensors involve metal–ligand interactions and to develop efficient extractants and chemical sensors, structural information about Pu ligands must be obtained by quantum calculations. Herein, six representative nitrogen tridentate ligands were introduced, and their binding stabilities were evaluated. The tridentate L6, which contains tri-pyridine chelate with benzene connectors, showed the highest binding energies for Pu(IV) and PuO2(VI) in water. Analysis based on the quantum theory of atoms in molecular analysis, including natural population analysis and electron density studies, provided insight into the bonding characteristics for each structure. We propose that differences in ionic bonding characteristics account for the Pu-ligand stability differences. These results form a basis for designing novel extractants and organic Pu sensors.

Highlights

Plutonium is very useful for energy production in a carefully controlled nuclear reactor
Representative nitrogen tridentate ligands were introduced and their binding properties were investigated by using two different levels of theory to obtain information that will aid the design of plutonium extractants and metal ion sensors in aqueous solution
quantum theory of atoms in molecules (QTAIM) analysis and natural population analysis (NPA) studies revealed the nature of the Pu–N and Pu–O bonds, and showed that highly ionic bonds account for the enhanced bonding strength and, the stability of these complexes

Summary

Introduction

Plutonium is very useful for energy production in a carefully controlled nuclear reactor. The nuclear power industry faces challenges related to the irradiation of nuclear fuels by used fuel recycled by a pyroprocessing system or PUREX (Pu and U Extraction) system Liquid waste from these systems contains highly toxic actinides, including Pu, which must be effectively extracted for reuse via a closed-loop recycling program, such that it does not contaminate the environment [5,6,7,8,9]. The efficiency of such programs depends on effective recycling of the spent nuclear fuel by separating the fissile Pu, which is formed by neutron capture reactions and is intended for subsequent use in a fast neutron reactor. Treh1e).mTohsitscroemsemarochnlayimussetdo Ncla-driofynothrelidgiaffnedrsenacneds itnhothsee bbainsdicinsgtrucacptuarbeislitairees ucothafteipsliiairzxbebitdolriintdifdeoesinrnotgtafhtcseihisxsaorstarftuticdtndeeiyrntirtso(atFgitceiegsns.uodrfetonn1oi)t.rrolTiggheainsnddreossnweoairtrhclihgPauani(dmIVss)wtaionthdcPlPauuriO(fIyV2 )(tVhaenI)ddinPifuwfeOaret2en(rVc,eIas)nidinntwotahinteevrbe, siantnidgdianttoge investigate their bonding characteristics

Results and Discussion

Computational Details

Conclusions