Herein we describe convenient lab scale syntheses of several uranium(iv) halides of high purity by reaction of AlX (X = Cl, Br and I) with UO, which is readily available by reduction of uranyl salts like UO(NO)·6HO. UCl, UBr, and UI are obtained in the form of aggregates of large single crystals. Their identities and purity were checked by powder X-ray diffraction, IR spectroscopy and elemental analysis. The syntheses introduced here avoid the need for pure metallic uranium and are based on more readily available starting materials, UO, which does not even have to be pure, and the respective aluminium halide. Chemical vapor transport (CVT) is applied in situ for purification of the products.
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http://dx.doi.org/10.1039/c7dt00726d | DOI Listing |
ACS Omega
April 2022
Philipps-Universität Marburg, Fachbereich Chemie, Hans-Meerwein-Str. 4, Marburg, Hessen 35032, Germany.
The reaction of the uranium(IV) halides UCl, UBr, or UI with ethyl acetate (EtOAc) leads to the formation of the complexes [UX(EtOAc)][UX(EtOAc)] (X = Cl, Br) or [UI(EtOAc)]. Thus, both UCl and UBr show self-ionization in ethyl acetate to a distorted pentagonal bipyramidal [UX(EtOAc)] cation and a distorted octahedral [UX(EtOAc)] anion. Surprisingly, the chloride and bromide compounds are not isotypic.
View Article and Find Full Text PDFInorg Chem
June 2021
Department of Chemistry, The University of Iowa, E331 Chemistry Building, Iowa City, Iowa 52242, United States.
Low-valent uranium coordination chemistry continues to rely heavily on access to trivalent starting materials, but these reagents are typically prepared from uranium turnings, which are becoming increasingly difficult to acquire. Here we report convenient syntheses of UI(THF) (THF = tetrahydrofuran) and UBr(THF) from UCl, a more accessible uranium starting material that can be prepared from commercially available uranium oxides. UCl(THF) (), UBr(THF) (), and UI(THF) () were prepared by single-pot reductions from UCl using KH and KC and converted to or by halide exchange with the corresponding MeSiX (where X = Br or I).
View Article and Find Full Text PDFNat Chem
October 2020
Anorganische Chemie, Fluorchemie, Fachbereich Chemie, Philipps-Universität Marburg, Marburg, Germany.
The aqueous chemistry of uranium is dominated by the linear uranyl cation [UO], yet the isoelectronic nitrogen-based analogue of this ubiquitous cation, molecular [UN], has so far only been observed in an argon matrix. Here, we present three different complexes of [UN] obtained by the reaction of the uranium pentahalides UCl or UBr with anhydrous liquid ammonia. The [UN] moieties are linear, with the U atoms coordinated by five additional ligands (ammonia, chloride or bromide), resulting in a pentagonal bipyramidal coordination sphere that is also commonly adopted by the uranyl cation [UO(L)] (L, ligand).
View Article and Find Full Text PDFChemistry
May 2019
Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße, 35032, Marburg, Germany.
The redetermination of the crystal structure of trigonal UCl , which is the eponym for the UCl structure type, showed that certain atomic coordinates had been incorrectly reported. This led to noticeably different U-Cl distances within the octahedral UCl molecule (2.41 and 2.
View Article and Find Full Text PDFDalton Trans
May 2017
Fachbereich Chemie Philipps-Universität Marburg, Hans-Meerwein-Str. 4, 35032 Marburg, Germany.
Herein we describe convenient lab scale syntheses of several uranium(iv) halides of high purity by reaction of AlX (X = Cl, Br and I) with UO, which is readily available by reduction of uranyl salts like UO(NO)·6HO. UCl, UBr, and UI are obtained in the form of aggregates of large single crystals. Their identities and purity were checked by powder X-ray diffraction, IR spectroscopy and elemental analysis.
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