Design criteria for tetradentate phenanthroline-derived heterocyclic ligands to separate Am(III) from Eu(III)

Chengliang Xiao, Qunyan Wu, Congzhi Wang, Yuliang Zhao, Zhifang Chai, Weiqun Shi

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

To design novel phenanthroline-derived soft ligands for selectively separating minor actinides from lanthanides, four tetradentate phenanthroline-derived heterocyclic ligands (BTPhen, BPyPhen, BPzPhen, and BBizPhen) were constructed and their complexation behaviors with Am(III) and Eu(III) were systematically investigated by density functional theory (DFT) coupled with relativistic small-core pseudopotential. In all the 1:1-type species, the metal ion is in the center of the cavity and coordinates with two nitrogen atoms (N1 and N1′) of the phenanthroline skeleton and the other two nitrogen atoms (N2 and N2′) of the auxiliary groups. The bond lengths of Am-N are comparable to or even shorter than those of Eu-N bonds because the ionic radii of Am(III) are larger than those of Eu(III). Additionally, the negative ΔΔG Am/Eu value for the reaction of [M(H2O)4(NO3)3] + L → ML(NO3)3 + 4H2O indicates that the complexation reaction of Am(III) is more energetically favorable than that of Eu(III); this can be considered as an important design criterion to screen phenanthroline-derived ligands for MA(III) extraction. According to this criterion, the selectivity of tetradentate phenanthroline-derived ligands for separating Am(III) over Eu(III) follows the order of BTPhen > BBizPhen > BPyPhen > BPzPhen.

Original languageEnglish (US)
Pages (from-to)1439-1448
Number of pages10
JournalScience China Chemistry
Volume57
Issue number11
DOIs
StatePublished - Sep 26 2014

Keywords

  • DFT
  • lanthanide
  • minor actinide
  • phenanthroline
  • separation

ASJC Scopus subject areas

  • Chemistry(all)

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