Gerken, Michael

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Browsing Gerken, Michael by Author "Goettel, James T."

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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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    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.
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    A new synthetic route to rhenium and iodine oxide fluoride anions: The reaction between oxoanions and sulfur tetrafluoride
    (Elsevier, 2015) Goettel, James T.; Turnbull, Douglas; Gerken, Michael
    Sulfur tetrafluoride is a reagent for the one-step syntheses of [ReVIIO2F4]−, [IVOF4]−, and [IVIIO2F4]− salts. Pure Ag[ReO2F4] as well as its CH3CN coordination compounds were obtained from CH3CN solvent. The Ag[ReO2F4], [Ag(CH3CN)2][ReO2F4], and [Ag(CH3CN)4][ReO2F4] salts were characterized by Raman spectroscopy. The [Ag(CH3CN)4][ReO2F4]·2CH3CN coordination compound was characterized by single-crystal X-ray diffraction. The reaction of SF4 with KIO4 in anhydrous HF gave the known K[IO2F4] salt. The reaction of [N(CH3)4]IO3 with SF4 in CH3CN yielded the new [N(CH3)4][IOF4] salt, which was characterized by Raman spectroscopy.
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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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    Synthesis and characterization of adducts between SF4 and oxygen bases: examples of O···S(IV) chalcogen bonding
    (American Chemical Society, 2016) Goettel, James T.; Gerken, Michael
    Lewis acid–base adducts between SF4 and the oxygen bases tetrahydrofuran, cyclopentanone, and 1,2-dimethoxyethane were synthesized and characterized by Raman spectroscopy and X-ray crystallography. Crystal structures of (SF4·OC4H8)2, SF4·(OC4H8)2, SF4·CH3OC2H4OCH3, and SF4·(O═C5H8)2 show weak S···O chalcogen bonding interactions ranging from 2.662(2) to 2.8692(9) Å. Caffeine, which has three Lewis basic sites, was reacted with SF4 and one aliquot of HF forming C8H10N4O2·2SF4·HF, which was also characterized by X-ray crystallography. Density functional theory calculations aided in the assignment of the vibrational spectra of (SF4·OC4H8)2, SF4·(OC4H8)2, SF4·CH3OC2H4OCH3, and SF4·(O═C5H8)2. Bonding was studied by natural bond order and the quantum theory of atoms in molecules analyses.
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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.