Syntheses, structures & bonding of high oxidation state main-group & transition metal fluoride derivatives

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This Proposal seeks funding for fundamental research in the field of synthetic and structural inorganic fluorine chemistry, and encompasses highly reactive fluorides and oxide fluorides of the main-group elements and of the heavy transition metal elements in their highest oxidation states. The described species are all synthetically challenging and highly air-sensitive, providing an excellent venue for the training of highly competent experimentalists in this strategic field. The compounds that are dealt with are frequently at the fringes of chemical stability and are highly energetic and strongly oxidizing, requiring highly specialized low-temperature handling techniques and chemically inert apparatus. Such compounds are of interest to the fundamental and applied chemist because of their aggressive chemical behaviours, novel bonding and structural features. These compounds span classical 2-centre - 2-electron and so-called "hypervalent" bonding and are often highly coordinated, greatly exceeding the 4 electron pairs in the valence shell that are associated with the classic "octet rule". The proposed chemistry, often at the edge of what is possible, will provide new structures that challenge, affirm and extend modern ideas of chemical bonding. A number of the fluorine compounds dealt with in this proposal, in particular noble-gas compounds, are among the strongest oxidants known and serve as progenitors to a number of other novel high-oxidation state species described in this Proposal. The training, technology and chemistry afforded by this program are relevant to industry and society. Although the vast majority of commercial fluorine compounds are organic (e.g., 20-25% of pharmaceuticals contain at least one fluorine), the preparation of any one of these compounds requires the use of inorganic fluorine compounds, e.g., HF, F2, BF3, or SF4. Inorganic fluorine compounds such as UF6, NF3, ClF3, SF6, HF, BF3, and XeF2 are absolutely critical (and without substitute) for the sustained existence and growth of the Nation's nuclear power generation, photovoltaic materials, semiconductor materials, refrigerants, advanced optics, pharmaceutical and agricultural compounds, 18F-radiopharmaceuticals for medical imaging and etchants for microelectronics.