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- ItemCrystal structure of (E)-dodec-2-enoic acid(Chester : International Union of Crystallography, 2015) Sonneck, Marcel; Peppel, Tim; Spannenberg, Anke; Wohlrab, SebastianThe crystal structure of (E)-dodec-2-enoic acid, C12H22O2, an [alpha],[beta]-unsaturated carbÂoxyÂlic acid with a melting point (295 K) near room temperature, is characterized by carbÂoxyÂlic acid inversion dimers linked by pairs of O-H...O hydrogen bonds. The carbÂoxyÂlic acid group and the following three carbon atoms of the chain of the (E)-dodec-2-enoic acid molÂecule lie almost in one plane (r.m.s. deviation for the four C atoms and two O atoms = 0.012 Ã…), whereas the remaining carbon atoms of the hydroÂcarbon chain adopt a nearly fully staggered conformation [moduli of torsion angles vary from 174.01 (13) to 179.97 (13)°].
- ItemCrystal structure of (E)-undec-2-enoic acid(Chester : International Union of Crystallography, 2015) Sonneck, Marcel; Peppel, Tim; Spannenberg, Anke; Wohlrab, SebastianIn the molÂecule of the title low-melting [alpha],[beta]-unsaturated carbÂoxyÂlic 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 Ã…). In the crystal, centrosymmetrically related molÂecules are linked by pairs of O-H...O hydrogen bonds into dimers, forming layers parallel to the (041) plane.
- ItemCrystal structure of di-n-butÂylÂbisÂ([eta]5-pentaÂmethylÂcycloÂpentaÂdienÂyl)hafnium(IV)(Chester : International Union of Crystallography, 2015) Arndt, Perdita; Schubert,Kathleen; Burlakov, Vladimir V.; Spannenberg, Anke; Rosenthal, UweThe crystal structure of the title compound, [Hf(C10H15)2(C4H9)2], reveals two independent molÂecules in the asymmetric unit. The diffraction experiment was performed with a racemically twinned crystal showing a 0.529 (5):0.471 (5) component ratio. Each HfIV atom is coordinated by two pentaÂmethylÂcycloÂpentaÂdienyl and two n-butyl ligands in a distorted tetraÂhedral geometry, with the cycloÂpentaÂdienyl rings inclined to one another by 45.11 (15) and 45.37 (16)°. In contrast to the isostructural di(n-butyl)bis([eta]5-pentaÂmethylÂcycloÂpentaÂdienÂyl)zirconium(IV) complex with a noticeable difference in the Zr-butyl bonding, the Hf-CbutÂyl bond lengths differ from each other by no more than 0.039 (3) Ã….
- ItemThermal annealing studies of GeTe-Sb2Te3 alloys with multiple interfaces(New York : American Institute of Physics, 2017) Bragaglia, Valeria; Mio, Antonio M.; Calarco, RaffaellaA high degree of vacancy ordering is obtained by annealing amorphous GeTe-Sb2Te3 (GST) alloys deposited on a crystalline substrate, which acts as a template for the crystallization. Under annealing the material evolves from amorphous to disordered rocksalt, to ordered rocksalt with vacancies arranged into (111) oriented layers, and finally converts into the stable trigonal phase. The role of the interface in respect to the formation of an ordered crystalline phase is studied by comparing the transformation stages of crystalline GST with and without a capping layer. The capping layer offers another crystallization interface, which harms the overall crystalline quality.
- ItemCrystal structure of bis(η5-cyclopenta-dienyl)(2, 3-diethylbutane-1, 4-diyl)-hafnium(IV)(Chester : International Union of Crystallography, 2015) Burlakov, Vladimir V.; Baumann, Wolfgang; Arndt, Perdita; Spannenberg, Anke; Rosenthal, UweThe title compound, [Hf(C5H5)2(C8H16)], proves a structural motif of hafnaÂcycloÂpentane besides the coordination of two cycloÂpentaÂdienyl ligands in an [eta]5-fashion. The hafnaÂcycloÂpentane ring has a twist conformation and is substituted by two ethyl groups in the [beta],[beta]'-positions, which are trans orientated to each other. One cycloÂpentaÂdienyl ring and one ethyl group are each disordered over two positions with site-occupancy ratios of 0.679 (15):0.321 (15) and 0.702 (18):0.298 (18), respectively.
- ItemCrystal structure of (E)-hex-2-enoic acid(Chester : International Union of Crystallography, 2015) Peppel, Tim; Sonneck, Marcel; Spannenberg, Anke; Wohlrab, SebastianThe crystal structure of the title compound, C6H10O2, an [alpha],[beta]-unsaturated carbÂoxyÂlic acid, displays carbÂoxyÂlic 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 molÂecule lie almost in the same plane (r.m.s. deviation for the non-H atoms = 0.018 Ã…).
- ItemCrystal structure of (E)-pent-2-enoic acid(Chester : International Union of Crystallography, 2015) Peppel, Tim; Sonneck, Marcel; Spannenberg, Anke; Wohlrab, SebastianThe molÂecule of the title compound, C5H8O2, a low-melting [alpha],[beta]-unsaturated carbÂoxyÂlic acid, is essentially planar [maximum displacement = 0.0239 (13) Ã…]. In the crystal, molÂecules are linked into centrosymmetric dimers via pairs of O-H...O hydrogen bonds.
- ItemCrystal structure of (1S,2R,4S)-1-[(morpholin-4-yl)-methyl]-4-(prop-1-en-2-yl)cyclohexane-1,2-diol(Chester : International Union of Crystallography, 2015) Outouch, Rachid; Oubaassine, Saadia; Ali, Mustapha Ait; El Firdoussi, Larbi; Spannenberg, AnkeThe asymmetric unit of the title compound, C14H25NO3, contains two independent molÂecules with similar geometry. The morpholine and cycloÂhexane rings of both molÂecules adopt a chair conformation. IntraÂmolecular O-H...N hydrogen bonds are observed. In the crystal, molÂecules are linked by O-H...O hydrogen bonds into chains parallel to the [101] direction. The chains are further connected through C-H...O hydrogen bonds forming undulating layers parallel to the (-101) plane. The absolute configuration was assigned by reference to an unchanging chiral centre in the synthetic procedure.
- ItemCrystal structure of bis(η5-cyclopenta-dienyl)(1,4-di-tert-butylbuta-1-en-3-yn-1-yl) zirconium(IV) μ2-hydroxido-bis[tris-(pentafluorophenyl) borate](Chester : International Union of Crystallography, 2015) Burlakov, Vladimir V.; Spannenberg, Anke; Arndt, Perdita; Rosenthal, UweAlkyl zirconocene cations have been of considerable interÂest as reactive species in many polymerization processes. In the crystal structure of the title compound, [Zr(C12H19)(C5H5)2](C36HB2F30O), the [Zr(C5H5)2((t-Bu)C=C(H)-C2(t-Bu))]+ cation displays a buta-1-en-3-yne ligand side-on coordinated to a typical bent zirconocene [centroid(cp)-Zr-centroid(cp) = 131.4 (3)°, Zr-C(buta-1-en-3-yne) = 2.255 (3), 2.597 (3) and 2.452 (2) Ã…]. In the [HO(B(C6F5)3)2]- anion, intraÂmolecular O-H...F hydrogen bonds are observed. One tert-butyl group in the complex cation is disordered over two sets of sites with occupancies 0.701(4):0.299(4).
- ItemUltrafast structural changes in SrTiO3 due to a superconducting phase transition in a YBa2Cu3O7 top layer(College Park, MD : Institute of Physics Publishing, 2010) Lübcke, A.; Zamponi, F.; Loetzsch, R.; Kämpfer, T.; Uschmann, I.; Große, V.; Schmidl, F.; Köttig, T.; Thürk, M.; Schwoerer, H.; Förster, E.; Seidel, P.; Sauerbrey, R.We investigate the structural response of SrTiO3 when Cooper pairs are broken in an epitaxially grown YBa2Cu3O 7 top layer due to both heating and optical excitation. The crystal structure is investigated by static, temperaturedependent and time-resolved x-ray diffraction. In the static case, a large strain field in SrTiO3 is formed in the proximity of the onset of the superconducting phase in the top layer, suggesting a relationship between both effects. For the time-dependent studies, we likewise find a large fraction of the probed volume of the SrTiO3 substrate strained if the top layer is superconducting. Upon optical breaking of Cooper pairs, the observed width of the rocking curve is reduced and its position is slightly shifted towards smaller angles. The dynamical theory of x-ray diffraction is used to model the measured rocking curves. We find that the thickness of the strained layer is reduced by about 200 nm on a sub-ps to ps timescale, but the strain value at the interface between SrTiO3 and YBa2Cu3O7 remains unaffected. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.