Gerken, Michael

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Browsing Gerken, Michael by Subject "Anions"

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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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    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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    Syntheses and characterization of W(NC6F5)F5– and W2(NC6F5)2F9– salts and computational studies of the W(NR)F5– (R = H, F, CH3, CF3, C6H5, C6F5) and W2(NC6F5)2F9– anions
    (American Chemical Society, 2017) Turnbull, Douglas; Wetmore, Stacey D.; Gerken, Michael
    Convenient preparative routes to fluorido[(pentafluorophenyl)imido]tungstate(VI) salts have been developed. The reaction of WF6·NC5H5 or [N(CH3)4][WF7] with C6F5NH2 results in quantitative formation of the C5H5NH+ or N(CH3)4+ salt of the W(NC6F5)F5– anion, respectively. The dissolution of [C5H5NH][W(NC6F5)F5] in anhydrous HF results in the formation of [C5H5NH][W2(NC6F5)2F9]. These salts have been comprehensively characterized in the solid state by X-ray crystallography and Raman spectroscopy and in solution by 19F and 1H NMR spectroscopy. The crystal structures of the W(NC6F5)F5– salts reveal conformational differences in the anions, and the 19F NMR spectra of these salts in CH3CN reveal coupling of the axial fluorido ligand to the 14N nucleus of the imido ligand. In addition, density functional theory (DFT-B3LYP) calculations have been performed on a series of W(NR)F5– anions (R = H, F, CH3, CF3, C6H5, C6F5) and the W2(NC6F5)2F9– anion, including gas-phase geometry optimizations, vibrational frequencies, molecular orbitals, and natural bond orbital (NBO) 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.
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    Synthesis, characterization, and Lewis acid behavior of [W(NC6F5)F4]x and computational study of W(NR)F4 (R = H, F, CH3, CF3, C6H5, C6F5), W(NC6F5)F4(NCCH3), and W(NC6F5)F4(NC5H5)n (n = 1, 2)
    (American Chemical Society, 2019) Turnbull, Douglas; Wetmore, Stacey D.; Gerken, Michael
    Amorphous [W(NC6F5)F4]x has been synthesized by the reaction of [C5H5NH][W(NC6F5)F5] with AsF5 in CH2Cl2. The reaction of [W(NC6F5)F4]x with CH3CN yields monomeric W(NC6F5)F4(NCCH3), whereas reaction with a sub-2-fold excess of C5H5N in CH3CN results in quantitative conversion to W(NC6F5)F4(NC5H5). Meanwhile, the reaction of W(NC6F5)F4(NCCH3) with a large excess of C5H5N results in the precipitation of W(NC6F5)F4(NC5H5)2. These compounds have been characterized in the solid state by Raman spectroscopy and in solution by multinuclear NMR spectroscopy. The crystal structures of W(NC6F5)F4(NCCH3) and W(NC6F5)F4(NC5H5), as well as improved structures of WOF4(NC5H5)n (n = 1, 2), have been obtained at low temperatures. Furthermore, density functional theory (DFT-B3LYP) calculations have been conducted on the W(NR)F4 (R = H, F, CH3, CF3, C6H5, C6F5) series as well as W(NC6F5)F4(NCCH3) and W(NC6F5)F4(NC5H5)n (n = 1, 2), providing optimized gas-phase geometries, vibrational frequencies, molecular orbitals, fluoride-ion affinities, and natural bond orbital (NBO) analyses.