Uptake of Am(III) Ions and Eu(III) Ions Using Cyclic Substituted N, O‐hybrid 1,10‐Phenanthroline Derived Phosphine Oxide Ligands ‐ A DFT Exploration

Abstract

The spent nuclear fuel has radioactive species such as actinides and lanthanides which hamper its reprocessing. This issue is undertaken by designing suitable organic ligands to strip off actinides from lanthanides. Due to the versatility of phenanthroline‐derived N, O‐donor ligands, we have looked into the electronic structure of N,O‐hybrid 1,10‐phenanthroline derived phosphine oxide ligands with various cyclic substitutions. The complexation behavior of these ligands with Am(III) and Eu(III) is evaluated using density functional theory calculations. Electronic structures divulge that in all these tetra‐coordinated complexes, the oxygen atoms bind strongly than the nitrogen atoms. The substitution of a benzene ring on the phosphorus increases the selectivity whereas the binding is enhanced by the substitution of cyclopentane. QTAIM analysis portrays the weak C−H−O interactions present in these complexes. Energy decomposition analysis in gas and solvent phases estimates the weak stabilizing interactions in these complexes. All the calculations bring out the salient structural features of these ligands which will further enrich our understanding of the tailoring of ligands for efficient uptake of Am (III) ions over Eu (III) ions.