Syntheses structure and bonding in main-group and high oxidation state transition metal fluorides & oxide fluorides

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This proposal seeks funding for several projects in synthetic and structural inorganic fluorine chemistry that encompass highly reactive fluorides and oxide fluorides of the main-group elements and of several heavy transition metal elements in their highest oxidation states. The species that are described are all highly air-sensitive and synthetically challenging, providing an excellent venue for the training of highly competent experimentalists. The compounds that are dealt with are frequently at the fringes of chemical stability and are therefore highly energetic (endothermic) and are often strongly oxidizing in nature, requiring highly specialized low-temperature handling techniques and chemically inert handling apparatus. The compounds that are described are of fundamental interest to the chemist because of their highly reactive natures and the novel bonding and structural features/geometries they display. The structures span the classical (2-center - 2-electron) bonds and so-called "hypervalent" bonds and are highly coordinated, often greatly exceeding the 4 electron pairs in the valence shell that are normally 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 bonding ideas. A number of the fluorine compounds, in particular noble-gas compounds, dealt with in this proposal, are also among the most reactive (oxidizing) species known and serve as progenitors to a number of the novel high-oxidation state species described in this proposal. The technology and chemistry developed in this program and previously funded NSERC Discovery Grants held by the PI has been relevant to Nuclear Medicine and to those who use 18F-labelled radiopharmaceuticals as imaging agents for PET (positron emission tomography) scans.  The fundamental fluoride and oxide fluoride chemistry of technetium is of direct relevance to the uranium re-enrichment cycle and to the environmental issues surrounding the decommissioning and clean up of the world's aging gaseous diffusion plants that have been used for re-enrichment of spent nuclear fuels.