Towards the origin of effective An(III)/Ln(III) separation by tridentate N-donor ligands: a theoretical study on atomic charges and polarisabilities for Cm(III)/Gd(III) separation
Аннотация:ABSTRACTSoft N-donor ligand have shown to separate An(III) from Ln(III). The origin of the selectivity has not been entirely identified, and similar ligands show very different separation qualities. In this study we present a theoretical investigation of several relevant N-donor ligands in terms of atomic charges and polarisabilities obtained from an atoms in molecules approach. These allow new insights into the bonds between the ligands' nitrogen atoms and the metal cation and explain a major part of the selectivity towards actinide ions. We deduct the superiority of 2,6-bis(1,2,4-triazine-3-yl)pyridines in separation quality compared to similar ligands for the Cm(III)/Gd(III) separation. Furthermore, improvements of existing ligands are developed that allow not only a direct experimental confirmation but also a systematic experimental study of the interactions and their influence on the selectivity.KEYWORDS: Actinide chemistryseparationN-donor ligandspolarisabilitiesquantum chemistry AcknowledgmentsWe acknowledge access to the computing resources provided by the Steinbuch Centre for Computing (SCC) at KIT. We would also like to thank Dr. Feiwu Chen from the University of Beijing; Dr. Michael Patzschke from the Helmholtz Zentrum Dresden-Rossendorf and Dr. Andreas Geist and Dr. Petra Panak from KIT for helpful discussions.Disclosure statementNo potential conflict of interest was reported by the authors.Additional informationFundingEuropean Commission and by the German Federal Ministry of Education and Research (BMBF):European FP7 TALISMAN project [Grant Number 02NUK020A].
