Gerken, Michael

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Browsing Gerken, Michael by Author "Kostiuk, Nathan"

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    Interactions between SF4 and fluoride: a crystallographic study of solvolysis products of SF4·nitrogen-base adducts by HF
    (American Chemical Society, 2016) Goettel, James T.; Kostiuk, Nathan; Gerken, Michael
    Adducts between SF4 and a nitrogen base are easily solvolyzed by HF, yielding the protonated nitrogen base and fluoride. Salts resulting from the solvolysis of SF4·NC5H5, SF4·NC5H4(CH3), SF4·NC5H3(CH3)2, and SF4·NC5H4N(CH3)2 have been studied by Raman spectroscopy and X-ray crystallography. Crystal structures were obtained for pyridinium salts [HNC5H5+]F–·SF4 and [HNC5H5+]F–[HF]·2SF4, the 4-methylpyridinium salt [HNC5H4(CH3)+]F–·SF4, the 2,6-methylpyridinium salt [HNC5H3(CH3)2+]2[SF5–]F–·SF4, and 4-(dimethylamino)pyridinium salts [HNC5H4N(CH3)2+]2[SF5–]F–·CH2Cl2 and [NC5H4N(CH3)2+][HF2–]·2SF4. In addition, the structure of [HNC5H4(CH3)+][HF2–] was obtained. 4,4′-Bipyridyl reacts with SF4 and 1 and 2 equiv of HF to give the 4,4′-bipyridinium salts [NH4C5–C5H4NH+]F–·2SF4 and [HNH4C5–C5H4NH2+]2F–·4SF4, respectively. These structures exhibit a surprising range of bonding modalities and provide an extensive view of SF4 and its contacts with Lewis basic groups in the solid state. The interactions range from the strong F4S–F– bond in the previously observed SF5– anion to weak F4S---F–, F4S(---F–)2, and F4S(---FHF–)2 dative bonds.
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    The solid-state structure of SF4: the final piece of the puzzle
    (Wiley, 2013) Goettel, James T.; Kostiuk, Nathan; Gerken, Michael
    Solved at last: The crystal structure of solid SF4, which has a melting point of −121 °C, has been obtained. It exhibits weak intermolecular S⋅⋅⋅F interactions. A similar structural motif was observed within a layer of SF4 in [HNC5H3(CH3)2+]2F−⋅⋅⋅SF4[SF5−]⋅3 SF4. The latter structure contains a range of bonding modes between S and F, namely SF5−, F4S⋅⋅⋅F−, F4S⋅⋅⋅FSF4−, and F4S⋅⋅⋅FSF3.
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    Syntheses, characterisation, and computational studies of tungsten hexafluoride adducts with pyridine and its derivatives
    (Elsevier, 2018) Turnbull, Douglas; Kostiuk, Nathan; Wetmore, Stacey D.; Gerken, Michael
    The reactions of WF6 with pyridine, 4-methylpyridine, 4-(dimethylamino)pyridine, and 4,4′-bipyridine (4,4′-bipy) in CH2Cl2 afford the Lewis-acid-base adducts WF6(4-NC5H4R) (R = H, CH3, N(CH3)2) and F6W(4,4′-bipy)WF6 as solids in quantitative yields. These adducts have been characterised in the solid state by Raman spectroscopy at ambient temperature and, in the cases of the mononuclear adducts, by X-ray crystallography at −173 °C. Furthermore, density-functional-theory (DFT-B3LYP) studies have been conducted to aid in predicting the structure of F6W(4,4′-bipy)WF6, assigning the vibrational frequencies of the adducts, and comparing their electronic properties.
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    Synthesis and characterization of SF4 adducts with polycyclic amines
    (American Chemical Society, 2020) Kostiuk, Nathan; Goettel, James T.; Gerken, Michael
    Chalcogen-bonding interactions of SF4 with the polycyclic amines DABCO (C6H12N2) and HMTA (C6H12N4) were studied by low-temperature Raman spectroscopy and X-ray crystallography, revealing the 2:1 adducts C6H12N2·2SF4 and C6H12N4·2SF4 obtained from SF4 solvent. In C6H12N2·2SF4, the sulfur in each SF4 molecule is pentacoordinate with each SF4 coordinated by a single amine group, whereas C6H12N4·2SF4 forms a one-dimensional coordination polymer with three of the four nitrogen atoms in HMTA exhibiting N---S chalcogen bonds: one terminal N---SF4 and one experimentally unprecedented bridging N---(SF4)---N moiety. Solvolysis of C6H12N2·2SF4 by HF yielded crystals of [C6H12N2H]+2F–[SF5]−·6SF4, in which SF4 acts as a chalcogen-bond donor toward N as well as F. Solvolysis of C6H12N4·2SF4 resulted in the formation of the monoprotonated HMTA salt [C6H12N4H]+[HF2]−·SF4. Excess HF also led to isolation of monoprotonated HTMA, as seen in the crystal structure of the [C6H12N4H]+[H2F3]−·HF salt. The reaction of bicyclic, monobasic quinuclidine with SF4 and HF gave [C7H13NH]+F–·3.5SF4, which contains N–H---F–---SF4 interactions, as well as an interstitial, disordered SF4 molecule.