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Author: Peppel, Tim × Subject: Crystal structure ×

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Now showing 1 - 6 of 6
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    Crystal structure of (E)-dodec-2-enoic acid
    (Chester : International Union of Crystallography, 2015) Sonneck, Marcel; Peppel, Tim; Spannenberg, Anke; Wohlrab, Sebastian
    The crystal structure of (E)-dodec-2-enoic acid, C12H22O2, an [alpha],[beta]-unsaturated carb­oxy­lic acid with a melting point (295 K) near room temperature, is characterized by carb­oxy­lic acid inversion dimers linked by pairs of O-H...O hydrogen bonds. The carb­oxy­lic acid group and the following three carbon atoms of the chain of the (E)-dodec-2-enoic acid mol­ecule lie almost in one plane (r.m.s. deviation for the four C atoms and two O atoms = 0.012 Å), whereas the remaining carbon atoms of the hydro­carbon chain adopt a nearly fully staggered conformation [moduli of torsion angles vary from 174.01 (13) to 179.97 (13)°].
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    Crystal structure of (E)-undec-2-enoic acid
    (Chester : International Union of Crystallography, 2015) Sonneck, Marcel; Peppel, Tim; Spannenberg, Anke; Wohlrab, Sebastian
    In the mol­ecule of the title low-melting [alpha],[beta]-unsaturated carb­oxy­lic acid, C11H20O2, the least-squares mean line through the octyl chain forms an angle of 60.10 (13)° with the normal to plane of the acrylic acid fragment (r.m.s. deviation = 0.008 Å). In the crystal, centrosymmetrically related mol­ecules are linked by pairs of O-H...O hydrogen bonds into dimers, forming layers parallel to the (041) plane.
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    Crystal structure of (E)-hex-2-enoic acid
    (Chester : International Union of Crystallography, 2015) Peppel, Tim; Sonneck, Marcel; Spannenberg, Anke; Wohlrab, Sebastian
    The crystal structure of the title compound, C6H10O2, an [alpha],[beta]-unsaturated carb­oxy­lic acid, displays carb­oxy­lic acid inversion dimers linked by pairs of O-H...O hydrogen bonds. The packing is characterized by layers of acid dimers. All the non-H atoms of the (E)-hex-2-enoic acid mol­ecule lie almost in the same plane (r.m.s. deviation for the non-H atoms = 0.018 Å).
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    Crystal structure of (E)-pent-2-enoic acid
    (Chester : International Union of Crystallography, 2015) Peppel, Tim; Sonneck, Marcel; Spannenberg, Anke; Wohlrab, Sebastian
    The mol­ecule of the title compound, C5H8O2, a low-melting [alpha],[beta]-unsaturated carb­oxy­lic acid, is essentially planar [maximum displacement = 0.0239 (13) Å]. In the crystal, mol­ecules are linked into centrosymmetric dimers via pairs of O-H...O hydrogen bonds.
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    New Low-Melting Triply Charged Homoleptic Cr(III)-Based Ionic Liquids in Comparison to Their Singly Charged Heteroleptic Analogues
    (Basel : MDPI AG, 2021) Peppel, Tim; Köckerling, Martin
    A series of new low-melting triply charged homoleptic Cr(III)-based ionic liquids of the general formula (RMIm)3[Cr(NCS)6] (R = methyl, ethyl, n-butyl, benzyl) is reported. Their syntheses and properties are described in comparison to their singly charged heteroleptic analogues of the general formula (RMIm)[Cr(NCS)4L2] (R = methyl, ethyl, n-butyl, benzyl; L = pyridine, γ-picoline). In total, sixteen new Reineckate related salts with large imidazolium cations are described. Out of these, five compounds were crystallized, and their structures determined by single-crystal X-ray structure analyses. They all consisted of discrete anions and cations with octahedrally coordinated Cr(III) ions. In the structures, various hydrogen contacts interconnect the entities to build up hydrogen bonded networks. Thermal investigations showed relatively low melting points for the homoleptic complexes. The compounds with the [Cr(NCS)6]3− anion melt without decomposition and are stable up to 200 K above their melting points. The complex salts with the [Cr(NCS)4L2]− anion, in contrast, start to decompose and lose L molecules (Pyr or Pic) already at the melting point.
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    Low-melting manganese(II)-based ionic liquids: Syntheses, structures, properties and influence of trace impurities
    (Basel : MDPI, 2019) Peppel, Tim; Geppert-Rybczyńska, Monika; Neise, Christin; Kragl, Udo; Köckerling, Martin
    The synthesis of more than 10 new magnetic ionic liquids with [MnX4]2− anions, X = Cl, NCS, NCO, is presented. Detailed structural information through single-crystal X-ray diffraction is given for (DMDIm)[Mn(NCS)4], (BnEt3N)2[Mn(NCS)4], and {(Ph3P)2N}2[Mn(NCO4)]·0.6H2O, respectively. All compounds consist of discrete anions and cations with tetrahedrally coordinated Mn(II) atoms. They show paramagnetic behavior as expected for spin-only systems. Melting points are found for several systems below 100 °C classifying them as ionic liquids. Thermal properties are investigated using differential scanning calorimetry (DSC) measurements. The physicochemical properties of density, dynamic viscosity, electrolytic conductivity, and surface tension were measured temperature-dependent of selected samples. These properties are discussed in comparison to similar Co containing systems. An increasing amount of bromide impurity is found to affect the surface tension only up to 3.3%.