f-Block Coordination Chemistry with Oxygen Donor Ligands in Ionic Liquids

Contained in this dissertation is an analysis of the fundamental chemistry of the f-block elements with oxygen donor ligands in ionic liquids. This work focuses heavily on the structures of the crystalline phases that form when lanthanides and actinides react with either phosphonates or borates in an ionothermal flux. It will be demonstrated in this work that this flux method is a valuable means of preparing new materials that would otherwise be unattainable using more conventional hydrothermal or solvothermal flux methods. The first project in this work focuses on the ionothermal flux synthesis of a series of new uranium phosphonates. Since the hydrothermal and solvothermal flux syntheses of uranium phosphonates had previously been extensively studied, this work provided a valuable proof of concept since there was a large body of reported structures to compare the products of the ionothermal flux reactions against. It was found that the topologies of the resulting crystalline phases were dictated equally by the choice of the ligand (e.g. aryl monophosphonate, alkyldiphosphonate, etc.), the choice of the flux method, and the choice of ionic liquid if an ionothermal flux was used. In the second project, a new series of trivalent f-element borates was synthesized using an ionothermal flux. While it was expected that the ionic liquid would act as both the solvent and the template in the synthesis of three-dimensional borate framework materials, what was actually observed was the formation of an isomorphous series of molecular tetranuclear borate cluster compounds. This is further evidence that an ionothermal flux may actually be responsible for limiting the dimensionality of structure topologies rather than facilitating the formation of templated extended networks.