The synthesis, structural, and spectroscopic characterization of uranium(IV) perrhenate complexes

Gordon H. John, Iain May, Clint A. Sharrad, Andrew D. Sutton, David Collison, Madeleine Helliwell, Mark J. Sarsfield

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

We report the synthesis, structural, and spectroscopic characterization of a series of uranium(IV)-perrhenato complexes. Three isostructural complexes with general formula [U(ReO4)4(L)4] (where L = tri-n-butylphosphine oxide/TBPO (2), triethyl phosphate/TEP (3), or tri-iso-butyl phosphate/TiBP (4)), have been synthesized, both through the photoreduction of ethanolic {UO2}2+ solutions and also via a novel UIV starting material, U(ReO4) 4·5H2O (1). Compound 1 has also been used in the preparation of [U(ReO4)4(TPPO)3(CH 3CN)]·2CH3CN (5) and [U(ReO4)- (DPPMO2)3(OH)][ReO4]2· 2CH3CN (6), where TPPO represents triphenylphosphine oxide and DPPMO2 represents bis(diphenylphosphino)methane dioxide. All six complexes have been spectroscopically characterized using NMR, UV-vis-NIR, and IR techniques, with 2, 3, 5, and 6 also fully structurally characterized. The U atoms in compounds 2-6 all exhibit eight-coordinate geometry with up to four perrhenate groups in addition to three (DPPMO2 and TPPO) or four (TEP, TiBP, TBPO) coordinated organic ligands. In the case of compounds 5 and 6, the coordination of eight ligands to the UIV center is completed by the binding of a solvent molecule (CH3CN) and OH-, respectively. Solid-state physical analysis (elemental and thermogravimetric) and infrared spectroscopy are in agreement with the structural studies. The crystallographic data suggest that the strength of the UIV-O-donor ligand bonds decreases across the series R3PO > [ReO4]-> (RO)3PO. Solution-state IR and 31P NMR spectroscopy appear to be in agreement with these solid-state results.

Original languageEnglish
Pages (from-to)7606-7615
Number of pages10
JournalInorganic Chemistry
Volume44
Issue number21
DOIs
StatePublished - Oct 17 2005
Externally publishedYes

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