Browsing by Author "Gelbrich, Thomas"

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  • Ammonium 6:2 fluorotelomer sulfonate: crystal structure, thermal analysis and use as internal standard in PFAS analysis
    (2025-04-15) Freilinger, Johanna; Gelbrich, Thomas; Braun, Doris E.; Griesser, Ulrich J.; Bakry, Rania; Kahlenberg, Volker; Müller, Thomas; Kreutz, Christoph; Nerdinger, Sven; Fliri, Lukas; Schottenberger, Herwig
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Alkali salts of the common fluorosurfactant 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-1-octanesulfonic acid (6:2 FTSA) exhibit a remarkably low solubility in water, which enables the precipitation of these salts from water. The same applies for the corresponding ammonium salt 6:2 FTS NH4 which can be obtained in crystalline form by slowly adding aqueous ammonia to an aqueous solution of FTSA. To understand the cause of this behavior on a molecular basis, an X-ray single crystal structure determination of 6:2 FTS NH4 was performed, allowing to further examine the molecular interactions in the solid state responsible for its low solubility. A hydrogen-bonded layer structure results from four distinct N‒H···O interactions, that involve all four NH groups, the given ammonium ion and sulfonate-O atoms belonging to four different anion units. Columns of parallel aligned fluoroalkyl chains dominate the packing of molecules in the crystal. The characterization was accompanied by thermal as well as spectroscopic analysis. The lack of hygroscopicity and its high thermal stability make 6:2 FTS NH4 a suitable gravimetric standard substance for analytical applications. HPLC MS/MS measurements showed that 6:2 FTS NH4 can adequately substitute commercial 13C labelled compounds at least for routine analysis of common perfluorinated contaminants using standard internal calibration.
  • Can't touch this: Highly omniphobic coatings based on self-textured C6-fluoroponytailed polyvinylimidazolium monoliths
    (2021-09) Partl, Gabriel Julian; Naier, Benjamin Florian Erich; Bakry, Rania; Schlapp-Hackl, Inge; Kopacka, Holger; Wurst, Klaus; Gelbrich, Thomas; Fliri, Lukas; Schottenberger, Herwig
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The quaternization of 1-vinylimidazole with 1H,1H,2H,2H-perfluorooctyl iodide, followed by anion metathesis reactions, allowed for the synthetic access of novel polymerizable fluorosurfactant salts with excellent yields, scalable from multigram up to bulk quantities on the kg scale. Subsequently, a series of doubly fluoroponytailed monomers as well as bridged bis-vinylimidazolium cross-linkers have been prepared via expedient thionation / S-alkylation. Thus, the resulting pool of these late stage intermediates offers great potential in task-specific surface tuning. Through polymerization in appropriate porogen mixtures combined with the micellar self-aggregation of the perfluoroalkyl moieties along with synergistic ionic interactions of the novel fluorosurfactants, the formation of nano-scalar monolithic structures is induced as evidenced by SEM imaging. According to contact angle measurements, the lotus-like textures hereby created drastically enhance oil and water repellency of the resulting polymer surface. Heeding the well-established cooperative concepts of chemical surface functionalization, accompanied by physical roughness, represents a proven strategy to impart high omniphobicity. However, the applicative maturity of systems based on nanophysics is frequently restricted by tedious and intricate patterning techniques as well as the environmental constraints of surface-active fluoroorganic compounds, on which high-performance systems indispensably rely.
  • A Fluoroponytailed NHC–Silver Complex Formed from Vinyl-imidazolium/AgNO3 under Aqueous– Ammoniacal Conditions
    (2022-07-01) Partl, Gabriel; Rauter, Marcus; Fliri, Lukas; Gelbrich, Thomas; Kreutz, Christoph; Müller, Thomas; Kahlenberg, Volker; Nerdinger, Sven; Schottenberger, Herwig
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    3-(1H,1H,2H,2H-Perfluorooctyl)-1-vinylimidazolium chloride [2126844–17–3], a strong fluorosurfactant with remarkably high solubility in water, was expediently converted into the respective doubly NHC-complexed silver salt with nitrate as counter ion in quantitative yield. Due to its vinyl substituents, [bis(3-(1H,1H,2H,2H-perfluorooctyl)-1-vinylimidazol-2-ylidene)silver(I)] nitrate, Ag(FNHC)2NO3, represents a polymerizable N-heterocyclic carbene transfer reagent, thus potentially offering simple and robust access to coordination polymers with crosslinking metal bridges. The compound was characterized by infrared and NMR spectroscopy, mass spectrometry as well as elemental analysis, and supplemented by X-ray single-crystal structure determination. It crystallizes in the monoclinic crystal system in the space group P21/c. With 173.3◦, the geometry of the Ag-carbene bridge deviates slightly from linearity. The disordered perfluoroalkyl side chains exhibit a helical conformation.
  • Ionic and neutral fluorosurfactants containing ferrocene moieties as chromophoric constituents
    (2021-01) Fliri, Lukas; Partl, Gabriel; Winkler, Daniel; Wurst, Klaus; Gelbrich, Thomas; Müller, Thomas; Schottenberger, Herwig; Hummel, Michael
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    In two eventually interlinked projects emphasizing on the exploitation of the peculiar properties of ferrocene moieties, as well as fluoroponytails, the two compounds (E)-1-ferrocenyl-2-(1-(1H,1H,2H,2H-perfluorooctyl)-4-pyridiniumyl)ethylene hexafluorophosphate and (4-perfluorooctylphenyl)ferrocene were prepared. Despite the crystallization of polyfluoroalkylated materials is usually very challenging, attempts to grow single-crystals suitable for X-ray determination were successful, allowing for a detailed structural discussion of ferrocene containing fluorosurfactants for the first time. Additionally, a tentative UV–vis study was performed in four solvents. In contrast to the commonplace spectral behavior of (4-perfluorooctylphenyl)ferrocene, different interesting features, including slight solvatochromism, peak-splitting at higher concentrations, as well as the formation of a colored dispersion were detected for the ionic dye (E)-1-ferrocenyl-2-(1-(1H,1H,2H,2H-perfluorooctyl)-4-pyridiniumyl)ethylene hexafluorophosphate.
  • Phase-out-compliant fluorosurfactants: Unique methimazolium derivatives including room temperature ionic liquids
    (2017) Hummel, M.; Markiewicz, M.; Stolte, S.; Noisternig, Michael; Braun, D. E.; Gelbrich, Thomas; Griesser, Ulrich J.; Partl, G.; Naier, B.; Wurst, Klaus; Krüger, B.; Kopacka, Holger; Laus, G.; Huppertz, H.; Schottenberger, H.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Expedient alkylations of 1-methyl-3H-imidazole-2-thione, a pharmaceutical active ingredient available in bulk quantities, provide high yield access to numerous protonated, or quaternized imidazoliums with chemospecific attachment of the fluoroponytail at the 2-mercapto functionality. The deprotonated primary target products represent valuable nitrogen heterocyclic bases, capable of further substitution, and salt or complex formation. Specific physicochemical characteristics that are relevant for phase and surface responsive behavior, e.g. critical micelle concentration, oleophobicity, depression of the aqueous surface tension, foam formation, emulsification of microgranular PTFE, are investigated for selected representatives and compared to the properties of common fluorosurfactants and ionic liquids. Remarkably, it is found that halogen bonding between iodide counterions of respective polyfluoroalkylmethimazolium systems and 1-iodoperfluoroalkanes, serving as the σ-hole partner of the halides, greatly affect the solubility profile of the resulting molecular adducts. Single-crystal X-ray structure determinations are carried out across the new fluorous substance classes. Strikingly, the helical arrangement of fluorine atoms along the chains typically encountered in polyfluorinated compounds is not found as the prevailing conformation. Rather, they are outnumbered by structural motifs exhibiting the rare zig-zag (linear alkane-like) chain conformation. Key derivatives are also subjected to preliminary ecotoxicological testing.