Gerken, Michael

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Browsing Gerken, Michael by Author "Mercier, Hélène P. A."

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    Fluoride-ion acceptor properties of WSF4: synthesis, characterization, and computational study of the WSF5¯ and W2S2F9¯ anions and 19F NMR spectroscopic characterization of the W2OSF9¯ anion
    (American Chemical Society, 2012) Nieboer, Jared; Haiges, Ralf; Hillary, William; Yu, Xin; Richardet, Tyler; Mercier, Hélène P. A.; Gerken, Michael
    The new [N(CH3)4][WSF5] salt was synthesized by two preparative methods: (a) by reaction of WSF4 with [N(CH3)4][F] in CH3CN and (b) directly from WF6 using the new sulfide-transfer reagent [N(CH3)4][SSi(CH3)3]. The [N(CH3)4][WSF5] salt was characterized by Raman, IR, and 19F NMR spectroscopy and [N(CH3)4][WSF5]·CH3CN by X-ray crystallography. The reaction of WSF4 with half an aliquot of [N(CH3)4][F] yielded [N(CH3)4][W2S2F9], which was characterized by Raman and 19F NMR spectroscopy and by X-ray crystallography. The WSF5– and W2S2F9– anions were studied by density functional theory calculations. The novel [W2OSF9]− anion was observed by 19F NMR spectroscopy in a CH3CN solution of WOF4 and WSF5–, as well as CH3CN solutions of WSF4 and WOF5–.
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    Lewis acid behavior of SF4: synthesis, characterization, and computational study of adducts of SF4 with pyridine and pyridine derivatives
    (Wiley, 2015) Chaudhary, Praveen; Goettel, James T.; Mercier, Hélène P. A.; Sowlati-Hashjin, Shahin; Hazendonk, Paul; Gerken, Michael
    Sulfur tetrafluoride was shown to act as a Lewis acid towards organic nitrogen-bases, such as pyridine, 2,6-dimethylpyridine, 4-methylpyridine, and 4-dimethylaminopyridine. The SF4·NC5H5, SF4·2,6-NC5H3(CH3)2, SF4·4-NC5H4(CH3), and SF4·4-NC5H4N(CH3)2 adducts can be isolated as solids that are stable below –45 °C. The Lewis acid-base adducts were characterized by low temperature Raman spectroscopy and the vibrational bands were fully assigned with the aid of density-functional-theory (DFT) calculations. The electronic structures obtained from the DFT calculations were analyzed by the quantum theory of atoms in molecules (QTAIM). The crystal structures of SF4·NC5H5, SF4·4-NC5H4(CH3), and SF4·4-NC5H4N(CH3)2 revealed weak S---N dative bonds with nitrogen coordinating in the equatorial position of SF4. Based on the QTAIM analysis, the non-bonded valence shell charge concentration on sulfur, which represents the lone pair, is only slightly distorted by the weak dative S---N bond. No evidence for adducts between quinoline or isoquinoline with SF4 was found by low-temperature Raman spectroscopy.