Dissertation/Thesis Abstract

Actinide Hybrid Materials: Experimental and Computational Metrics for Assembly
by Surbella, Robert Gian, III, Ph.D., The George Washington University, 2018, 405; 10743264
Abstract (Summary)

This dissertation captures efforts to utilize supramolecular chemistry to prepare actinide hybrid materials across a range of compositions, e.g. [AnO2Cl4]2– (An = U, Np, Pu), [UO 2(NCS)4(H2O)]2– and [AmCl 6]3–, and as such, an overview of assembly criteria including synthetic strategies and methods to influence the resulting structural motifs is presented. Beyond this, we have begun to establish metrics (both crystallographic and computational) to evaluate assembly, by reconciling non-covalent interaction (NCI) pairings and structural motifs, and also by quantifying the strengths of the NCIs to develop a ranking scheme or hierarchy of interaction types. These efforts have allowed systematic syntheses of families of related materials, and are presented within the context of delineating structure-property relationships.

The supramolecular assembly of both uranium and transuranic (TRU) containing materials is dependent upon the ability to promote desired molecular building units (tectons) that can be assembled through ‘synthons’ consisting of hydrogen or halogen bonds. Promotion of such a tecton is achieved by manipulating U and TRU species in aqueous, high-anion media to promote controlled speciation and oxidation state profiles. This approach has generated an array of tectons containing the actinyl cations, [AnO2]2+ (An = U, Np, Pu) and low valent Pu and Am chlorides for instance, that were in turn assembled via NCI donating pyridinium cations. Crystals of resulting materials were characterized crystallographically, and the assembly criteria assessed using a combination of experimental and computational techniques including density functional theory and electrostatic potential mapping. In total, these efforts have brought supramolecular assembly concepts utilized elsewhere on the periodic table to the 5f block. This has resulted in 41 novel compounds and has allowed for the role of the NCI in An chemistry to be explored in concert with that of metal ion coordination environment and charge across AnO22+ (An = U(VI), Np(VI) and Pu(VI)) and Pu and An(III) species.

Indexing (document details)
Advisor: Cahill, Christopher L.
Commitee: Besson, Claire C.G., Voutchkova-Kostal, Adelina
School: The George Washington University
Department: Chemistry
School Location: United States -- District of Columbia
Source: DAI-B 79/08(E), Dissertation Abstracts International
Subjects: Chemistry, Inorganic chemistry
Keywords: Actinide, Halogen bond, Hydrogen bond, Supramolecular, Transuranic, Uranyl
Publication Number: 10743264
ISBN: 978-0-355-83017-0
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