This dissertation seeks to determine the differences in the lanthanides and later actinides in non-aqueous media. Research in the f-elements is significantly understudied compared to the other metals of the periodic table. Even more so are the later actinides which were largely unstudied for an extended period as it was believed later actinides were identical to lanthanides. A review by Neidig et al, “The Covalency in f-element Complexes” has ignited significant interest in the bonding of the actinides.1 A tremendous amount of research in the f-elements, particularly the actinides, has been performed in aqueous conditions at high temperatures and pressures. Chemistry under these conditions limit the research possible for lower oxidation states. Additionally, non-aqueous techniques allow for the investigation of these elements in more organic environments. The goal of this work is to pave a greater understanding of knowledge for lanthanides and actinides by examining their redox and coordination chemistries in these environments that could lead to applications other than nuclear energy and weapons. The first portion of this dissertation examines the chemistry that is already heavily acknowledged about f-elements: coordination chemistry. When modeling later actinides, a common notion is to utilize the isoelectronic lanthanide as the surrogate. Although for electronic comparisons this is useful, it is often not the case for examining isostructural compounds. The isoelectronic lanthanide is often smaller in ionic radius, which is a factor that dominates the chemistry of the lanthanides. Despite this, isolation of isostructural coordination compounds was obtained for the isoelectronic and size analogs of americium; europium and neodymium. This seemingly mundane study showed that americium portrays a small amount of covalency in its bonds which is not observed in the lanthanides. These small differences lead to profound changes in chemical properties as observed later in this work. The second portion of this work focuses on analyzing the divalent oxidation state of f-elements with crown ethers. The divalent oxidation state has been obtained for all lanthanides using potassium and 2.2.2-cryptand. The next step was to determine the extent to which crown ethers and solvents have on the redox properties of f-elements. Because all the lanthanides had been obtained in the divalent oxidation state in a similar matter, it was expected that the redox chemistries would behave identically. To surprise, ytterbium behaves differently and shows greater reversibility than the most stable divalent lanthanide, europium. Additionally, it was found that californium also behaves like ytterbium electrochemically, even though it would be expected to behave like samarium. It was proposed that this may be attributed to the 5f orbitals. The last of this work involves obtaining californium in the divalent oxidation state as a molecular system. This was done by modeling with samarium which is the most similar to californium in its redox and coordination properties. Quick and simple routes to synthesizing divalent samarium structures were obtained in ordinary glovebox conditions for attempts with californium. Under identical reaction conditions, isolation of Cf(II) crystals in the solid state were unsuccessful. However, interesting spectroscopic properties where observed that portrayed divalent californium as having tunable luminescence similar to divalent europium compounds. To our surprise, even though samarium resembles californium, the chemistry between the two elements are very different, further broadening the gap between the 4f and 5f elements. / A Dissertation submitted to the Department of Chemistry and Biochemistry in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Fall Semester 2018. / September 28, 2018. / Actinides, Californium and Americium, Coordination Chemistry, Divalent Samarium, Lanthanides, Redox Chemistry / Includes bibliographical references. / Thomas E. Albrecht-Schmitt, Professor Directing Dissertation; Samuel L. Tabor, University Representative; Kenneth G. Hanson, Committee Member; Yan-Yan Hu, Committee Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_709854 |
| Contributors | White, Frankie D. (author), Albrecht-Schmitt, Thomas E. (Professor Directing Dissertation), Tabor, Samuel L. (University Representative), Hanson, Kenneth G. (Committee Member), Hu, Yan-yan (Committee Member), Florida State University (degree granting institution), College of Arts and Sciences (degree granting college), Department of Chemistry and Biochemistry (degree granting departmentdgg) |
| Publisher | Florida State University |
| Source Sets | Florida State University |
| Language | English, English |
| Detected Language | English |
| Type | Text, text, doctoral thesis |
| Format | 1 online resource (119 pages), computer, application/pdf |
Page generated in 0.0024 seconds