Bis(cyclopentadienyl) actinide(IV) compounds. I. The structure of dichlorobis(pentamethyl-η5-cyclopentadienyl)uranium(IV) and dichlorobis(pentamethyl-η5-cyclopentadienyl)thorium(IV)

Spirlet, M. R.; Rébizant, J.; Apostolidis, Christos; Kanellakopulos, Β.

doi:10.1107/s0108270192003603

Cited by 42 publications

(37 citation statements)

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“…UCl 4 reacts with two equivalents of [(C 5 Me 4 SiMe 3 )MgCl(thf)] to produce [(C 5 Me 4 SiMe 3 ) 2 UCl 2 ] ( 1 ) as a crystalline maroon product in 92 % yield in a reaction analogous to the formation of [(C 5 Me 5 ) 2 UCl 2 ] (Scheme ) 1. The structural parameters of 1 , determined by X‐ray crystallography, are very similar to those of [(C 5 Me 5 ) 2 UCl 2 ] 21. The large trimethylsilyl groups of the (C 5 Me 4 SiMe 3 ) − ligand point up and away from the uranium center and therefore do not distort the metallocene moiety significantly from that of the (C 5 Me 5 ) − complex.…”

Section: Methodsmentioning

confidence: 83%

“…[1] The structural parameters of 1, determined by X-ray crystallography, are very similar to those of [(C 5 Me 5 ) 2 UCl 2 ]. [21] The large trimethylsilyl groups of the (C 5 Me 4 SiMe 3 ) À ligand point up and away from the uranium center and therefore do not distort the metallocene moiety significantly from that of the (C 5 Me 5 ) À complex. The addition of two equivalents of solid LiMe to a solution of 1 in toluene over 5 min generates [(C 5 Me 4 SiMe 3 ) 2 UMe 2 ] (2) as an orange crystalline product in 93 % yield after 12 h of stirring (Scheme 1).…”

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confidence: 99%

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Synthesis and Reactivity of a Silylalkyl Double Tuck‐in Uranium Metallocene [(η⁵:η¹‐C₅Me₄SiMe₂CH₂)₂U] and its Conversion to Bis(tethered) Metallocenes

Evans¹,

Siladke²

2010

Chemistry A European J

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Section: Methodsmentioning

confidence: 83%

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confidence: 99%

Synthesis and Reactivity of a Silylalkyl Double Tuck‐in Uranium Metallocene [(η⁵:η¹‐C₅Me₄SiMe₂CH₂)₂U] and its Conversion to Bis(tethered) Metallocenes

Evans¹,

Siladke²

2010

Chemistry A European J

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“…In 1978, Manriquez et al [5] reported new thorium and uranium derivatives containing two pentamethylcyclopentadienyl (Cp* = η 5 -C 5 Me 5 ) rings. Two An(IV) halides Cp 2 *ThCl 2 and Cp 2 *UCl 2 were successfully characterized by single-crystal X-ray diffraction in 1992; these complexes were found to have pseudo-tetrahedral "bent metallocene" geometries with C 2v symmetry [6]. Subsequently, Rabinovich et al [7] prepared a Th(IV) analog Cp 2 *ThBr 2 , which shows a similar structure to Cp 2 *UCl 2 .…”

Section: Introductionmentioning

confidence: 99%

Binuclear trivalent and tetravalent uranium halides and cyanides supported by cyclooctatetraene ligands

Wang

Lan

et al. 2016

Radiochimica Acta

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Although the first organoactinide chloride Cp 3 UCl (Cp = η 5 -C 5 H 5 ) was synthesized more than 50 years ago, binuclear uranium halides remain very rare in organoactinide chemistry. Herein, a series of binuclear trivalent and tetravalent uranium halides and cyanides with cyclooctatetraene ligands, (COT) 2 U 2 X n (COT = η 8 -C 8 H 8 ; X = F, Cl, CN; n = 2, 4), have been systematically studied using scalarrelativistic density functional theory (DFT). The structures with bridging halide or cyanide ligands were predicted to be the most stable complexes of (COT) 2 U 2 X n , and all the complexes show weak antiferromagnetic interactions between the uranium centers. However, for each species, there is no significant uranium-uranium bonding interaction. The bonding between the metal and the ligands shows some degree of covalent character, especially between the metal and terminal halide or cyanide ligands. The U-5f and 6d orbitals are predominantly involved in the metal-ligand bonding. All the (COT) 2 U 2 X n species were predicted to be more stable compared to the mononuclear half-sandwich complexes at room temperature in the gas phase such that (COT) 2 U 2 X 4 might be accessible through the known (COT) 2 U complex. The tetravalent derivatives (COT) 2 U 2 X 4 are more energetically favorable than the trivalent (COT) 2 U 2 X 2 analogs, which may be attributed to the greater number of strong metal-ligand bonds in the former complexes.

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“…This increase in bond distance is consistent with literature trends among other uranium-halide compounds. 150,169,173,175,176 Another important feature of these compounds to note is that the bipyridine-like structure is no longer reduced (as it is for (C5Me5)2U(2,2'-bpy) 165 ) in all but the fluorine compound. This can be seen through the bond length of the 2,2' bond between pyridine rings.…”

Section: Crystal Structuresmentioning

confidence: 99%

“…Very few similar compounds exist in the literature; listed in Table 28 are select bond distances and angles for (C5Me5)2UF2(py), 150 (C5Me5)2UCl2, 176 (C5Me5)2UBr2, 173 and (C5Me5)2UI2. 175 The bond length between uranium and the halide is longer in most of the compounds prepared in this work compared to (C5Me5)2UX2.…”

Section: Crystal Structuresmentioning

confidence: 99%

Synthesis of Actinide Materials for the Study of Basic Actinide Science and Rapid Separation of Fission Products

Dorhout

2017

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This dissertation covers several distinct projects relating to the fields of nuclear forensics and basic actinide science. Post-detonation nuclear forensics, in particular, the study of fission products resulting from a nuclear device to determine device attributes and information, often depends on the comparison of fission products to a library of known ratios. The expansion of this library is imperative as technology advances. Rapid separation of fission products from a target material, without the need to dissolve the target, is an important technique to develop to improve the library and provide a means to develop samples and standards for testing separations. Several materials were studied as a proof-of-concept that fission products can be extracted from a solid target, including microparticulate (< 10 µm diameter) dUO2, porous metal organic frameworks (MOFs) synthesized from depleted uranium (dU), and other organicbased frameworks containing dU. The targets were irradiated with fast neutrons from one of two different neutron sources, contacted with dilute acids to facilitate the separation of fission products, and analyzed via gamma spectroscopy for separation yields. The results indicate that smaller particle sizes of dUO2 in contact with the secondary matrix KBr yield higher separation yields than particles without a secondary matrix. It was also discovered that using 0.1 M HNO3 as a contact acid leads to the dissolution of the target material. Lower concentrations of acid were used for future experiments. In the case of the MOFs, a larger pore size in the framework leads to higher separation yields when contacted with 0.01 M HNO3. Different types of frameworks also yield different results. The second portion of this dissertation describes efforts to better understand electronic structure and bonding of the actinide metals in various environments. One project involved studying thorium and uranium bonding with the soft-donor chalcogenides, specifically sulfur. Results from these studies include the synthesis and characterization of the novel (C5Me5)2Th(SMe)2 complex; the synthesis of (C5Me5)2ThS5 by myriad routes, indicating the product is a thermodynamic sink; and evidence that sulfur is inserted iv into the thorium-carbon bond of (C5Me5)2ThMe2 to form the pentasulfide. The second project involved unique activation of the strong carbon-halide bonds present in benzyl-halides mediated by a uranium-(2,2'-bipyridine) complex. The resultant products include a series of uranium-halide bonds from fluoride to iodide, and the addition of the benzyl group to the bipyridine ring. Studies of the mechanism indicate that the benzyl group is added first to the 6 position of the ring before migrating to its final place at the 4 position. The final project utilized a novel gold-tetrazolate complex that can be tailored to add highnitrogen ligands to actinides in a facile and safe way. This transfer ligand was used to synthesize new uranium-tetrazolate species. A brief exploration into using the transfer ligand to add tetra...

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Bis(cyclopentadienyl) actinide(IV) compounds. I. The structure of dichlorobis(pentamethyl-η5-cyclopentadienyl)uranium(IV) and dichlorobis(pentamethyl-η5-cyclopentadienyl)thorium(IV)

Cited by 42 publications

References 4 publications

Synthesis and Reactivity of a Silylalkyl Double Tuck‐in Uranium Metallocene [(η⁵:η¹‐C₅Me₄SiMe₂CH₂)₂U] and its Conversion to Bis(tethered) Metallocenes

Synthesis and Reactivity of a Silylalkyl Double Tuck‐in Uranium Metallocene [(η⁵:η¹‐C₅Me₄SiMe₂CH₂)₂U] and its Conversion to Bis(tethered) Metallocenes

Binuclear trivalent and tetravalent uranium halides and cyanides supported by cyclooctatetraene ligands

Synthesis of Actinide Materials for the Study of Basic Actinide Science and Rapid Separation of Fission Products

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Bis(cyclopentadienyl) actinide(IV) compounds. I. The structure of dichlorobis(pentamethyl-η5-cyclopentadienyl)uranium(IV) and dichlorobis(pentamethyl-η5-cyclopentadienyl)thorium(IV)

Cited by 42 publications

References 4 publications

Synthesis and Reactivity of a Silylalkyl Double Tuck‐in Uranium Metallocene [(η5:η1‐C5Me4SiMe2CH2)2U] and its Conversion to Bis(tethered) Metallocenes

Synthesis and Reactivity of a Silylalkyl Double Tuck‐in Uranium Metallocene [(η5:η1‐C5Me4SiMe2CH2)2U] and its Conversion to Bis(tethered) Metallocenes

Binuclear trivalent and tetravalent uranium halides and cyanides supported by cyclooctatetraene ligands

Synthesis of Actinide Materials for the Study of Basic Actinide Science and Rapid Separation of Fission Products

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Synthesis and Reactivity of a Silylalkyl Double Tuck‐in Uranium Metallocene [(η⁵:η¹‐C₅Me₄SiMe₂CH₂)₂U] and its Conversion to Bis(tethered) Metallocenes

Synthesis and Reactivity of a Silylalkyl Double Tuck‐in Uranium Metallocene [(η⁵:η¹‐C₅Me₄SiMe₂CH₂)₂U] and its Conversion to Bis(tethered) Metallocenes