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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

FUTHER INVESTIGATION OF URANIUM IMIDO COMPOUNDS

Isabella Marie Portal (16630662) 21 July 2023 (has links)
<p>Uranium imido compounds have been traditionally studied due to their analogous nature to uranyl compounds. The investigation of uranium imido bonds can open the door to the activation of uranium oxygen bonds, which is important for the recyclization of spent nuclear fuel. This research encompasses further characterization of imido compounds utilizing electrochemical techniques which will better the understanding of these compounds. Utilizing what we already know about uranium imido compounds, further reactivity studies were conducted. Additionally, uranium is a suitable candidate for modeling synthesis of transuranic elements, specifically neptunium. Therefore, additional pathways to synthesize uranium tris(imido) and uranium tertrakis(imido) complexes were explored as a modeling system.  </p>
2

EXPLORING URANYL-OXO ACTIVATION VIA IMIDO SUBSTITUENTS AND EXPANDING THE LIBRARY OF URANIUM MULTIPLE IMIDO COMPLEXES

Tyler S Collins (12441156) 21 April 2022 (has links)
<p>Uranium imido complexes are highly sought after for their analogous nature to the uranyl moiety. Because of the highly reactive characteristics of uranium imido bonds compared to uranyl oxygen bonds these complexes have been used to investigate chemistry that can be used to activate the uranyl moiety. The activation of the <em>trans</em>-oxo groups of the uranyl moiety would open the door for the recycling of spent nuclear waste, diverting these chemicals from long term storage to a second life beyond nuclear fission. A suitable analog to the uranyl moiety has been discovered with the uranium bis(imido) family of complexes, these complexes can participate in chemistry that is similar if not, exactly the same as uranyl complexes. Studies with the uranium bis(imido) complex have been used to probe uranyl reactivity because the analogous nature of the two moieties. With that a uranium(IV) <em>cis</em>-bis(imido) complex was synthesized demonstrating how electron donation to the metal center can disrupt the Inverse Trans Influence (ITI) can as a result activate the <em>trans</em>-ligands on uranium. This complex is the first reported U(IV) bis(imido) with <em>trans</em> imido groups and achieved this geometry without large steric ligands to facilitate the <em>cis</em>- geometry. Computational analysis of this complex shows the stable nature of the geometry and how the fundamental electronics of this complex are the leading factor in the resultant geometry. When reactivity of the <em>cis</em>-bis(imido) was explored via protonation experiments a unique U(V) complex was isolated.</p> <p>Additional protonation reactivity was explored using UO2(tBubpy)(NTSA)2 with a variety of anilines to synthesize uranyl imido complexes. These experiments showed that the electronic environment—not the steric profile—of the anilines has a much greater effect on the stability of the resulting uranyl imido. The resulting uranyl imido complexes demonstrate the analogous nature of uranyl and uranium imido chemistry.</p> <p>Activation of the <em>trans</em>-imido groups on uranium bis(imido) complexes has also been shown with the synthesis of the uranium tris- and tetrakis(imido) complexes. These later complexes have shown that increased electron donation to the uranium metal center weakens and elongates the imido bonds, exposing these compounds to reactivity previously unavailable to uranium compounds with fewer multiply bound groups. </p>

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