Wetmore, Stacey

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https://opus.uleth.ca/handle/10133/4547

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Browsing Wetmore, Stacey by Subject "Cations"

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    Solid-state structure of a protonated ketones and aldehydes
    (Wiley, 2017) Stuart, Daniel; Wetmore, Stacey D.; Gerken, Michael
    Protonated carbonyl compounds have been invoked as intermediates in many acid-catalyzed organic reactions. To gain key structural and electronic data about such intermediates, oxonium salts derived from five representative examples of ketones and aldehydes are synthesized in the solid state, and characterized by X-ray crystallography and Raman spectroscopy for the first time. DFT calculations were carried out on the cations in the gas phase. Whereas an equimolar reaction of the carbonyl compounds, acetone, cyclopentanone, adamantanone, and acetaldehyde, with SbF5 in anhydrous HF yielded mononuclear oxonium cations, the same stoichiometry in a reaction with benzaldehyde resulted in formation of a hemiprotonated, hydrogen-bridged dimeric cation. Hemiprotonated acetaldehyde was obtained when a 2:1 ratio of aldehyde and SbF5 was used. Experimental and NBO analyses quantify the significant increase in electrophilicity of the oxonium cations compared to that of the parent ketones/aldehydes.
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    Stabilization of [WF5]+ by bidentate N-donor ligands
    (Wiley, 2019) Turnbull, Douglas; Wetmore, Stacey D.; Gerken, Michael
    Transition-metal hexafluorides do not exhibit fluoride-ion donor properties in the absence of donor ligands. We report the first synthesis of donor-stabilized [MF5]+ derived from a transition-metal hexafluoride via fluoride-ion abstraction using WF6(L) (L=2,2′-bipy, 1,10-phen) and SbF5(OSO) in SO2. The [WF5(L)][Sb2F11] salts and [WF5(1,10-phen)][SbF6]⋅SO2 have been characterized by X-ray crystallography, Raman spectroscopy, and multinuclear NMR spectroscopy. The reaction of WF6(2,2′-bipy) with an equimolar amount of SbF5(OSO) reveals an equilibrium between [WF5(2,2′-bipy)]+ and the [WF4(2,2′-bipy)2]2+ dication, as determined by 19F NMR spectroscopy. The geometries of the cations in the solid state are reproduced by gas-phase geometry optimizations (DFT-B3LYP), and NBO analyses reveal that the positive charges of the cations are stabilized primarily by compensatory σ-electron donation from the N-donor ligands.