Monomers, Dimers, and Helices: Complexities of Cerium and Plutonium Phenanthrolinecarboxylates

Samantha K. Cary, Maryline G. Ferrier, Ryan E. Baumbach, Mark A. Silver, Juan Lezama Pacheco, Stosh A. Kozimor, Henry S. La Pierre, Benjamin W. Stein, Alexandra A. Arico, Danielle L. Gray, Thomas E. Albrecht-Schmitt

Research output: Contribution to journalArticlepeer-review


The reaction of CeIII or PuIII with 1,10-phenanthroline-2,9-dicarboxylic acid (PDAH2) results in the formation of new f-element coordination complexes. In the case of cerium, Ce(PDA)(H2O)2Cl·H2O (1) or [Ce(PDAH)(PDA)]2[Ce(PDAH)(PDA)] (2) was isolated depending on the Ce/ligand ratio in the reaction. The structure of 2 is composed of two distinct substructures that are constructed from the same monomer. This monomer is composed of a CeIII cation bound by one PDA2- dianionic ligand and one PDAH- monoanionic ligand, both of which are tetradentate. Bridging by the carboxylate moieties leads to either [Ce(PDAH)(PDA)]2 dimers or [Ce(PDAH)(PDA)]1 helical chains. For plutonium, Pu(PDA)2 (3) was the only product isolated regardless of the Pu/ligand ratio employed in the reaction. During the reaction of plutonium with PDAH2, PuIII is oxidized to PuIV, generating 3. This assignment is consistent with structural metrics and the optical absorption spectrum. Ambiguity in the assignment of the oxidation state of cerium in 1 and 2 from UV-vis-near-IR spectra invoked the use of Ce L3,2-edge X-ray absorption near-edge spectroscopy, magnetic susceptibility, and heat capacity measurements. These experiments support the assignment of CeIII in both compounds. The bond distances and coordination numbers are also consistent with these assignments. 3 contains 8-coordinate PuIV, whereas the cerium centers in 1 and 2 are 9- and/or 10-coordinate, which correlates with the increased size of CeIII versus PuIV. Taken together, these data provide an example of a system where the differences in the redox behavior between these f elements creates more complex chemistry with cerium than with plutonium.

Original languageEnglish (US)
Pages (from-to)4373-4380
Number of pages8
JournalInorganic Chemistry
Issue number9
StatePublished - May 2 2016

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry


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