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- ItemCrystal structure of diethyl (E)-2-[(benzofuran-2-yl)methylidene]succinate(Chester : International Union of Crystallography, 2015) Schirmer, Marie-Luis; Spannenberg, Anke; Werner, ThomasThe title compound, C17H18O5, was synthesized by a base-free catalytic Wittig reaction. The molÂecule consists of a diethyl itaconate unit, which is connected via the C=C double bond to a benzoÂfuran moiety. The benzoÂfuran ring system (r.m.s. deviation = 0.007 Ã…) forms dihedral angles of 79.58 (4) and 12.12 (10)° with the mean planes through the cis and trans ethÂoxyÂcarbonyl groups, respectively. An intraÂmolecular C-H...O hydrogen bond involving the O atom of the benzoÂfuran moiety is observed. In the crystal, molÂecules are linked into ribbons running parallel to the b axis by C-H...O hydrogen bonds.
- ItemCrystal structure of bis{μ2-[(2-iminocyclopentylidene)methylidene]azanido-κ2 N:N'}bis[(η5-pentamethylcyclopentadienyl)zirconium(IV)] hexane monosolvate(Chester : International Union of Crystallography, 2015) Becker, Lisanne; Spannenberg, Anke; Arndt, Perdita; Rosenthal, UweThe title compound, [Zr2(C10H15)4(C6H6N2)2]·C6H14, was obtained by the stoichiometric reaction of adipoÂnitrile with [Zr(C10H15)2([eta]2-Me3SiC2SiMe3)]. IntraÂmolecular nitrile-nitrile couplings and deprotonation of the substrate produced the (1-imino-2-enimino)ÂcycloÂpentane ligand, which functions as a five-membered bridge between the two metal atoms. The ZrIV atom exhibits a distorted tetraÂhedral coordination sphere defined by two pentaÂmethylÂcycloÂpentaÂdienyl ligands, by the imino unit of one (1-imino-2-enimino)ÂcycloÂpentane and by the enimino unit of the second (1-imino-2-enimino)ÂcycloÂpentane. The cycloÂpentane ring of the ligand shows an envelope conformation. The asymmetric unit contains one half of the complex and one half of the hexane solvent molÂecule, both being completed by the application of inversion symmetry. One of the pentaÂmethylÂcycloÂpentaÂdienyl ligands is disordered over two sets of sites with a refined occupancy ratio of 0.8111 (3):0.189 (3). In the crystal, the complex molÂecules are packed into rods extending along [100], with the solvent molÂecules located in between. The rods are arranged in a distorted hexaÂgonal packing.
- 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 structures of two ansa-titanocene tri-fluoro-methane-sulfonate complexes bearing the Me2Si(C5Me4)2 ligand(Chester : International Union of Crystallography, 2016) Kessler, Monty; Godemann, Christian; Spannenberg, Anke; Beweries, TorstenThe crystal structures of two ansa-titanocene tri-fluoro-methane-sulfonate complexes bearing the Me2Si(C5Me4)2 ligand are reported, namely [di-methylbis-(η5-tetra-methyl-cyclo-penta-dien-yl)silane](tri-fluoro-methane-sulfonato-κ2O,O')titanium(III) toluene monosolvate, [Ti(CF3O3S)(C20H30Si)]·C7H8, 1, and chlorido-[di-methyl-bis-(η5-tetra-methyl-cyclo-penta-dien-yl)silane](tri-fluoro-methane-sulfonato-κO)titanium(IV), [Ti(CF3O3S)(C20H30Si)Cl], 2. Both complexes display a bent metallocene unit, the metal atom being coordinated in a distorted tetra-hedral geometry, with the tri-fluoro-methane-sulfonate anion acting as a bidentate or monodentate ligand in 1 and 2, respectively. In 1, weak π-π stacking inter-actions involving the toluene solvent mol-ecules [centroid-to-centroid distance = 3.9491 (11) Å] are observed.
- 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….
- 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 1,1,2,2-tetramethyl-1,2-bis(2,3,4,5-tetramethylcyclopenta-2,4-dien-1-yl)disilane(Chester : International Union of Crystallography, 2015) Godemann,Christian; Spannenberg, Anke; Beweries, TorstenThe molÂecular structure of the title compound, C22H38Si2, features a trans arrangement of the cycloÂpentaÂdienyl rings to avoid steric strain [C-Si-Si-C torsion angle = -179.0 (5)°]. The Si-Si bond length is 2.3444 (4) Ã…. The most notable interÂmolecular interÂactions in the molÂecular packing are C-H...[pi] contacts that lead to the formation of wave-like supraÂmolecular chains along the b axis.