Structures of homoleptic eight- and nine-coordinate uranium(IV) perchlorate complexes with sulfoxide molecules as ligands

Nobuyoshi Koshino, Yoshihiro Kachi, Tamás R. Varga, Attila C. Benyei, Motoo Shiro, Koichiro Takao, Yasuhisa Ikeda

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Homoleptic eight- and nine-coordinate U(IV) perchlorate complexes with sulfoxide ligands have been characterized crystallographically. Crystals of [U(dmso)8](ClO4)4 · 0.75CH3NO2, [U(dmso)9](ClO4)4 · 4dmso (dmso = dimethyl sulfoxide), and [U(tmso)8](ClO4)4 · 2tmso (tmso = tetramethylene sulfoxide) were found to have dodecahedral, tricapped trigonal prismatic, and square antiprismatic geometries, respectively. Average U-O bond distances in [U(dmso)8](ClO4)4 · 0.75CH3NO2, [U(dmso)9](ClO4)4 · 4dmso, and [U(tmso)8](ClO4)4 · 2tmso are 2.35(3), 2.41 (4), and 2.35(3) Å, respectively. Furthermore, it was found that [U(dmso)8]4+ is in equilibrium with [U(dmso)9]4+ in CH3NO2 solution containing dmso. Thermodynamic parameters for such an equilibrium are as follows: K (25 °C) = 3.4 ± 0.2 dm3 mol-1, ΔH = -54.9 ± 4.5 kJ mol-1, and ΔS = -174 ± 15 J K-1 mol-1.

Original languageEnglish
Pages (from-to)3433-3439
Number of pages7
JournalInorganica Chimica Acta
Issue number10
Publication statusPublished - Aug 1 2009



  • Crystal structure
  • Eight- and nine-coordination
  • Equilibrium reaction
  • Homoleptic complexes
  • Sulfoxide
  • Uranium(IV)

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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