Graduate Thesis Or Dissertation
 

Uranyl Peroxide Cluster Formation Pathway and the Role of the Alkali Counterion

Öffentlich Deposited

Herunterladbarer Inhalt

PDF Herunterladen
https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/05742003s

Descriptions

Attribute NameValues
Creator
Abstract
  • Uranyl peroxide clusters are the newest family of polyoxometalates, discovered in 2015. Although this family is new, over 70 topologies have been reported. However, we lack the fundamental understanding of assembly mechanisms, particularly the role of the alkali countercations. Here, we use a wide range of solution and solid-state characterization techniques to understand the formation of uranyl peroxide clusters and the role of the alkali countercation in the stabilization and destabilization of peroxide. In Chapter 2 we report the reaction pathway and assembly of uranyl peroxide capsules by tracking the conversion from K+ uranyl triperoxide monomer to the K+ uranyl-peroxide U28 capsule. For the first time, the K+ uranyl-peroxide pentamer face is isolated and structurally characterized. In Chapter 3, we have developed a general procedure to isolate different fragments of the uranyl peroxide clusters, using organic solvents to partially remove K+-salts from crude solids of the monomer building block UO2(O2)34- (U1), leading to stabilization of these reactive fragments. Higher polarity organic solvents remove more K+-salts from the crude solid, owing to higher solubility, resulting in more extensive linking of uranyl peroxide building-units. By this strategy we have isolated and structurally characterized a dimer K6[(UO2)2(O2)4(OH)2] 7∙H2O (K-U2) and a hexamer face frequently observed in the capsules, K12[(UO2)6(O2)9(OH)6]xH2O (K-U6). In Chapter 4, we study the reactivity of U1 and the effect of changing the counter-cation by successfully isolated the Rb-U1 and Cs-U1. We have found the reactivity of U1 increases with increasing alkali size. To understand the role the alkali plays in the stabilization and destabilization of peroxide, we study the reactions between alkali and peroxide in a hydrogen peroxide and alkali hydroxide mixture. In these two systems, a clear reactivity trend is established, with Li+ being the most stable and Cs+ the most reactivity, except for Rb+ in the alkali-peroxide studies. Most importantly, we have found that in the presence of Cs+ peroxide reduces uranium from U(VI) (Cs-U1) to U(V) (CsUO3). This is currently being studied. Lastly, in chapter 4, we thoroughly characterize TMA-Un the largest uranyl peroxide cluster isolated to date.
License
Resource Type
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Committee Member
Academic Affiliation
Urheberrechts-Erklärung
Publisher
Peer Reviewed
Language
Embargo reason
  • Pending Publication
Embargo date range
  • 2020-08-24 to 2022-09-25

Beziehungen

Parents:

This work has no parents.

In Collection:

Artikel

Miniaturansicht Titel Hochladedatum Sichtbarkeit Aktionen
file details ArteagaAna2020.pdf 2020-08-24 Öffentlich Herunterladen