skip to main content


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, [Et 4N] 4[Pu IV(NCS) 8], [Et 4N] 4[Th IV(NCS) 8], and [Et 4N] 4[Ce III(NCS) 7(H 2O)] are reported. Thiocyanate was found to rapidly reduce plutonium to Pu III in acidic solutions (pH<1) in the presence of NCS . The optical spectrum of [Et 4N][SCN] containing Pu III solution was indistinguishable from that of aquated Pu III suggesting that inner-sphere complexation with [Et 4N][SCN] does not occur in water. However, upon concentration, the homoleptic thiocyanate complex [Et 4N] 4[Pu IV(NCS) 8] was crystallized when a large excess of [Et 4N][NCS] was present. This compound, along with its U IV 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 An IV–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:
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
OSTI Identifier: