Browsing by Author "Stene, Riane E."
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- Discrete Mono-, Di-, and Trinuclear Anions [MoOF5]−, [MoVOF5]2-, [MoO2F4]2-, [Mo2O2F9]−, [Mo3O3F13]−, and the Infinite Chain Anion [MoO2F3]− Obtained from Reactions of MoOF4: Synthesis and Analysis of the Structure-Chemical Relations of the Compounds
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2023-08-21) Wassermann, Tobias B.; Stene, Riane E.; Scheibe, Benjamin; Karttunen, Antti J.; Kraus, FlorianThe herein-reported oxyfluoridometallate salts were synthesized and structurally characterized during the studies of the Lewis acidity of MOF4 (M = Mo, W) with various fluoride ion donors (RbF, CsF, TlF, AgF, SrF2, BaF2, PbF2) in different solvents (aqHF 48%, aHF, BrF3, ClF3). Phase-pure MoOF4 was either synthesized by hydrolysis of MoF6 with SiO2 in anhydrous HF (aHF) or by reactions of BrF3 with MoO2 or MoO3, respectively. The compound was characterized by infrared and Raman spectroscopy, solid-state quantum-chemical calculations, as well as powder and single-crystal X-ray diffraction. MoOF4 reacted with PbF2 in aHF forming Pb[MoOF5]2, while under comparable conditions, WOF4 formed Pb3[WOF5]4F2, containing the [WOF5]− anion. Salts containing such [MoOF5]− anions were also directly obtained from reactions of BrF3, MoO3, and AF2 (A = Sr, Ba), while with AgF, the compound Ag[Mo2O2F9] was observed. ClF3 reacted with MoO3 to form [ClOF2][Mo3O3F13]. Carrying out similar reactions in aqueous HF (aqHF) in autoclaves under hydrofluorothermal conditions leads to O-richer compounds with the composition A[MoO2F4] (A = Sr, Ba). With RbF or Tl2(CO3), the compounds A[MoO2F3] (A = Rb, Tl) were obtained. With CsF reduction to Mo(V) occurred as Cs2[MoVOF5] was formed. We report on similarities and differences within the respective anions and within the crystal structures of these compounds. - Lewis Acidic Behavior of MoOF4 towards the Alkali Metal Fluorides in Anhydrous Hydrogen Fluoride Solutions
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2019-01-01) Stene, Riane E.; Scheibe, Benjamin; Karttunen, Antti J.; Petry, Winfried; Kraus, FlorianPrevious studies performed on samples of MoOF4 dissolved in anhydrous hydrogen fluoride (aHF) solutions have indicated the presence of the [Mo2O2F9]– anion. Building upon this earlier work, MoOF4, and MF (M = Li–Cs) were dissolved in aHF solutions to produce M[Mo2O2F9] (M = Li–Cs) salts. Structural analysis of the obtained compounds was performed using single-crystal X-ray diffraction. This study provides the first single crystal structures for the [MoVI 2O2F9]– anion. Additionally, IR and Raman spectroscopy were used to characterize each salt. These spectra were compared to calculated ones for the solid-state structure of each salt using the DFT-PBE0 density functional method. The calculated spectra were used to give band assignments in the experimentally obtained spectra. - MoF5 revisited. A comprehensive study of MoF5
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2018-07-01) Stene, Riane E.; Scheibe, Benjamin; Pietzonka, Clemens; Karttunen, Antti J.; Petry, Winfried; Kraus, FlorianWhile the properties of molybdenum pentafluoride, MoF5, have been investigated in the past, there exists no comprehensive study of the compound. Additionally, many of these studies appear incoherent and offer contradictory explanations of some of the observed properties of MoF5. Consequently, a comprehensive examination of MoF5 is presented here, including a redetermination of the crystal structure of MoF5 using single crystal and powder X-ray diffraction, the reevaluation of its IR, Raman and UV–Vis spectrum, and a study of its density (3.50(2) g/cm3 @ 25 °C) and magnetic properties. Additionally, density functional theory (DFT) calculations were performed on the gas phase molecule Mo4F20 to provide a discussion of properties realized during investigation. Single crystal X-ray diffraction showed MoF5 to crystalize in the monoclinic, C2/m space group, as isolated tetramers having the formula Mo4F20. Magnetic measurements showed that when “MoF5” is cooled from the melt fast enough, paramagnetic species with S = ½ are present together with S = 0 species. These species may be described using the formula (MoF5)n (n = odd) and (MoF5)n (n = even, presumably n = 4). From the measurements, the content of the S = ½ species is estimated to be 6%. The preferred species of MoF5 under ambient conditions is Mo4F20. - A Symmetric F−H−F Hydrogen Bond in Strontium Bifluoride, Sr[HF2]2
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2022-05-25) Stene, Riane E.; Graubner, Tim; Ivlev, Sergei I.; Karttunen, Antti J.; Kraus, FlorianSingle crystal X-ray diffraction shows the hydrogen bond within the [F−H−F]− anion of Sr[HF2]2 to be symmetric with H−F bond lengths of 1.143(5) Å and an intramolecular F⋅⋅⋅F distance of 2.2826(18) Å. The [HF2]− anion adopts crystallographic C2-symmetry, however, it is essentially linear with a F−H−F angle of 174(4)°. Solid-state quantum chemical calculations agree with the experimental findings, showing a slightly bent F−H−F angle of 177.8°. The decomposition of Sr[HF2]2 to SrF2 and HF is endothermic by +64 kJ/mol at room temperature. The bonding in the [F−H−F]− anion is clearly ionic both in the solid state and gas phase. - Synthesis and Characterization of A[W2O2F9] (A = Li – Cs)
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2020-06-23) Stene, Riane E.; Scheibe, Benjamin; Karttunen, Antti J.; Petry, Winfried; Kraus, FlorianHerein, we report upon the in situ formation of WOF4 and its subsequent reaction with AF (A = Li – Cs) in aHF to produce A[W2O2F9] (A = Li – Cs). Structural analysis of the obtained compounds was performed using single-crystal X-ray diffraction. A comparison of the single-crystal structures obtained here to the previously reported A[Mo2O2F9] (A = Li – Cs) and H3O[W2O2F9] salts is given. Additionally, IR and Raman spectroscopy were used to characterize each salt. These spectra were compared to calculated ones for the solid-state structure of each salt using the DFT-PBE0 density functional method. The calculated spectra were used to assign bands in the experimental spectra. Both MoOF4 and WOF4 gave similar reaction products under similar reaction conditions. It was concluded that the oxyfluorides show similar Lewis acid-base reactions with the alkali metal fluorides in aHF solutions.