Doctor of Philosophy (PhD)
Chemistry and Biochemistry
First Committee Member
Kenneth R. Czerwinski
Second Committee Member
Third Committee Member
Fourth Committee Member
Number of Pages
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 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 tetrazolates to lanthanides was also done. All resultant compounds from each of these projects was studied by NMR, IR, and UV-Vis-NIR spectroscopies, electrochemistry, and X-ray crystallography.
Organometallics; Radiochemistry; Thorium; Uranium
Dorhout, Jacquelyn M., "Synthesis of Actinide Materials for the Study of Basic Actinide Science and Rapid Separation of Fission Products" (2017). UNLV Theses, Dissertations, Professional Papers, and Capstones. 3125.
Available for download on Saturday, December 15, 2018