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Title: Coordination Chemistry of Homoleptic Actinide(IV)-Thiocyanate Complexes

Here, the synthesis, X-ray crystal structure, vibrational and optical spectroscopy for the eight-coordinate thiocyanate compounds, [Et4N]4[PuIV(NCS)8], [Et4N]4[ThIV(NCS)8], and [Et4N]4[CeIII(NCS)7(H2O)] are reported. Thiocyanate was found to rapidly reduce plutonium to PuIII in acidic solutions (pH<1) in the presence of NCS. The optical spectrum of [Et4N][SCN] containing PuIII solution was indistinguishable from that of aquated PuIII suggesting that inner-sphere complexation with [Et4N][SCN] does not occur in water. However, upon concentration, the homoleptic thiocyanate complex [Et4N]4[PuIV(NCS)8] was crystallized when a large excess of [Et4N][NCS] was present. This compound, along with its UIV analogue, maintains inner-sphere thiocyanate coordination in acetonitrile based on the observation of intense ligand-to-metal charge-transfer bands. Spectroscopic and crystallographic data do not support the interaction of the metal orbitals with the ligand π system, but support an enhanced AnIV–NCS interaction, as the Lewis acidity of the metal ion increases from Th to Pu.
 [1] ;  [1]
  1. Argonne National Lab. (ANL), Argonne, IL (United States)
Publication Date:
OSTI Identifier:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Chemistry - A European Journal
Additional Journal Information:
Journal Volume: 21; Journal Issue: 44; Journal ID: ISSN 0947-6539
ChemPubSoc Europe
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22), Chemical Sciences, Geosciences, and Biosciences Division
Country of Publication:
United States
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; actinoids; coordination chemistry; plutonium; thiocyanates