DOTP versus DOTA as Ligands for Lanthanide Cations: Novel Structurally Characterized CeIV and CeIII Cyclen-Based Complexes and Clusters in Aqueous Solutions

Gev Dovrat, Svetlana Pevzner, Eric Maimon, Radion Vainer, Olga Iliashevsky, Yeshayahu Ben-Eliyahu, Philippe Moisy, Armand Bettelheim, Israel Zilbermann

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

The coordination and redox chemistry of aqueous CeIV/III macrocyclic compounds were studied by using the ligands DOTA and DOTP (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetraacetic acid and 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetra(methylene phosphonic acid), respectively). The hydrolysis tendency of the tetravalent cation in the presence of DOTA is shown to result in the formation of a highly ordered, fluorite-like [CeIV6(O)4(OH)4(H2O)8(DOTAH)4] oxo-hydroxo structure both in solution and in the solid state. The lifetime of the analogous species formed in the presence of DOTP was found to be much shorter. Spectroscopic measurements of the latter suggest its similarity to the former. Its gradual decomposition in solution leads to the accumulation of the in-cage complexes [CeIVDOTP] and [CeIIIDOTP(H2O)], which were crystallographically characterized in this study. The redox energetics and spectroscopic characteristics for the transition between these two in-cage complexes in aqueous solutions were studied as well. Together with the crystallographic structures of the above-mentioned species, the in-cage [CeIVDOTA(H2O)] complex structure is presented herein for the first time. An elaborative analysis of the X-ray crystallographic structural data obtained for the in-cage complexes studied herein and similar structures published previously suggests that hard-bonding cyclen-derived ligands are, counter-intuitively, better suited for encapsulating, and perhaps kinetically stabilize softer cations than harder ones with DOTP, marked as a possible adequate chelator for the study of the aqueous properties of LnII and AcIII cations.

Original languageEnglish
Article numbere202201868
JournalChemistry - A European Journal
Volume28
Issue number61
DOIs
StatePublished - 2 Nov 2022

Keywords

  • cerium
  • cluster compounds
  • coordination chemistry
  • macrocyclic ligands
  • redox chemistry
  • structure

ASJC Scopus subject areas

  • Catalysis
  • General Chemistry
  • Organic Chemistry

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