Synthetic Exploration of F-Element Borates and Plumbites

Despite their discovery during the 1940's, there are still many unanswered questions surrounding the elements past uranium, or transuranic elements. In the recent years more evidence is emerging that suggest the bonding and structure of the actinides in more complex than previous thought. We look to expand on this by judicious choice of ligands as a means of probing the bonding observed in actinide complexes. Towards the exploration of the nature of bonding in the actinide, the development of trends for ligand interaction is a goal. Currently, there is very little to indicate which ligands will show more covalent interactions or which will show more ionic interactions. Examining ligand systems that demonstrate a variety of characteristics, various oxoanions have been chosen over the traditional carbon based ligands. It is reasonable to view f-element interactions with oxoanions as metal ligand interactions and an excellent system to study displaying a variety of characteristics. Currently the overall softness and polarizablity of ligands is the only characteristic that lends some insight to the potential for covalency. However the choice of oxoanions makes the application of polarizablity a guide difficult. Through use of the quantified hyperpolarizability of oxoanions a guide to discriminate between anions with lower polarizablity such as phosphite and those with higher polarizablity such as molybdate. With the higher degree of polarizablity indicated by the hyperpolarizability, more covalent bonds with actinide metals are expected leading to unusual properties and differences when compared with lanthanide. Though traditional mild hydrothermal methods have proved suitable for the synthesis of crystalline products, there are limits to the method. To expand the synthetic versatility of the lab and access new hydrothermal phase space autoclaves for synthesis in supercritical media were developed. In particular supercritical water is a desirable synthetic media for crystal growth owing to characteristics as a solvent and the ability to access oxidations of metals otherwise inaccessible to mild hydrothermal methods. This dissertation is focused on the development of synthetics methods for the isolation and characterization of new f-element materials. To this end, each chapter reports on the synthetic methods and the novel f-element materials that incorporate highly polarizable oxoanions.