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- Item1-Diphenylphosphanyl-2-(diphenylphosphoryl)hydrazine(Chester : IUCr, 2018) Höhne, Martha; Aluri, Bhaskar; Spannenberg, Anke; Müller, Bernd H.; Peulecke, Normen; Rosenthal, UweThe title compound, C24H22N2OP2, is an asymmetrically substituted hydrazine derivative bearing a phosphoryl and a phosphanyl substituent. The PNNP backbone has a torsion angle of −131.01 (8)°. In the crystal, molecules form centrosymmetric dimers by intermolecular N—H...O hydrogen bonds, which are further linked into a three-dimensional network by weak C—H...O and C—H...π interactions.
- ItemTetracarbonyl[N-(diphenylphosphanyl-κP)-N,N′-diisopropyl-P-phenylphosphorus diamide-κP]molybdenum(0) with an unknown solvent(Chester : IUCr, 2018) Höhne, Martha; Gongoll, Marc; Spannenberg, Anke; Müller, Bernd H.; Peulecke, Normen; Rosenthal, UweThe title complex, [Mo(C24H30N2P2)(CO)4], contains a molybdenum centre bearing a P,P′-cis-chelating Ph2PN(iPr)P(Ph)NH(iPr) and four carbonyl ligands in a distorted octahedral coordination geometry. This results in a nearly planar four-membered metallacycle. In the crystal, molecules are linked by N—H...O and C—H...O hydrogen bonds to form layers parallel to the ac plane. For the final refinement, the contributions of disordered solvent molecules were removed from the diffraction data with SQUEEZE in PLATON [Spek (2015). Acta Cryst. C71, 9–18]. The given chemical formula and other crystal data do not take into account the unknown solvent molecule(s).
- Item3,3′-Dimethyl-1,1′-methylenediimidazolium tetrabromidocobaltate(II)(Chester : IUCr, 2018) Peppel, Tim; Spannenberg, AnkeThe title compound, (C9H14N4)[CoBr4], was obtained as single crystals directly in very low yield as a side product in the reaction of 1,1′-bis(1-methylimidazolium)acetate bromide and CoBr2. The title compound consists of an imidazolium-based dication and a tetrabromidocobaltate(II) complex anion, which are connected via C—H...Br interactions in the crystal. The dihedral angle between the imidazolium rings in the cation is 72.89 (16)°. The CoII ion in the anion is coordinated tetrahedrally by four bromide ligands [Co—Br = 2.4025 (5)–2.4091 (5) Å and Br—Co—Br = 106.224 (17)–113.893 (17)°]. The compound exhibits a high melting point (>300°C) and is a light-blue solid under ambient conditions.
- ItemTetracarbonyl-2κ4C-[μ-5-methyl-1,1,3-triphenyl-2-(propan-2-yl)-2,4-diaza-1,3-diphosphahexan-4-ido-1κN4:2κP1,P3](N,N,N′,N′-tetramethylethane-1,2-diamine-1κ2N,N′)lithiummolybdenum(Chester : IUCr, 2018) Höhne, Martha; Spannenberg, Anke; Müller, Bernd H.; Peulecke, Normen; Rosenthal, UweThe title complex, [LiMo(C6H16N2)(C24H29N2P2)(CO)4], contains a distorted octahedrally coordinated molybdenum centre bearing a lithiated P,P′-cis-chelating PNPN ligand, which results in a nearly planar four-membered metallacycle. The Li atom is coordinated by one equivalent tetramethylethylenediamine. In the crystal, molecules are linked via weak C—H...O interactions, forming a chain along the b-axis direction.
- ItemA second polymorph of 3,4-bis(6-bromopyridin-3-yl)-1,2,5-thiadiazole(Chester : International Union of Crystallography, 2016) Becker, Lisanne; Altenburger, Kai; Spannenberg, Anke; Arndt, Perdita; Rosenthal, UweThe title compound, C12H6Br2N4S, a second polymorph in the triclinic space group P-1, is presented. As in the earlier reported monoclinic polymorph in the space group C2/c [Becker et al. (2016[Becker, L., Reiss, F., Altenburger, K., Spannenberg, A., Arndt, P., Jiao, H. & Rosenthal, U. (2016). Chem. Eur. J. In the press. doi: 10.1002/chem.201601337.]). Chem. Eur. J. In the press], the thiadiazole ring is planar with an r.m.s. deviation of 0.004 Å. The five-membered ring is tilted with respect to the two pyridyl substituents by 23.16 (7) and 49.47 (9)°. In the crystal, molecules are linked by a weak non-bonding Br⋯N interaction [3.056 (3) Å]. Furthermore, a column of molecules is established along the b axis by π–π stacking interactions between the pyridine rings [centroid–centroid distances = 3.7014 (16) and 3.5934 (15) Å]. Additionally, a short intermolecular Br⋯Br contact [3.3791 (6) Å] and Br⋯π-aryl contacts [3.6815 (11)–3.7659 (12) Å] towards the thiadiazole and pyridine rings are found.
- Item1,1-Bis(diphenylphosphoryl)hydrazine(Chester : International Union of Crystallography, 2018) Höhne, Martha; Aluri, Bhaskar R.; Spannenberg, Anke; Müller, Bernd H.; Peulecke, Normen; Rosenthal, UweThe title compound, C24H22N2O2P2, contains a diphosphazane backbone, as well as a hydrazine entity. The P—N—P diphosphazane unit and the N-amine N atom are almost coplanar, and the O atoms of the Ph2P(O) units are oriented trans to each other with respect to the P...P axis. In the crystal, centrosymmetrically related molecules are linked into dimers by pairs of N—H...O hydrogen bonds, forming rings of graph-set motif R22(10).
- 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 molecule consists of a diethyl itaconate unit, which is connected via the C=C double bond to a benzofuran moiety. The benzofuran ring system (r.m.s. deviation = 0.007 Å) forms dihedral angles of 79.58 (4) and 12.12 (10)° with the mean planes through the cis and trans ethoxycarbonyl groups, respectively. An intramolecular C-H...O hydrogen bond involving the O atom of the benzofuran moiety is observed. In the crystal, molecules are linked into ribbons running parallel to the b axis by C-H...O hydrogen bonds.
- ItemHydrolysis Stability of Bidentate Phosphites Utilized as Modifying Ligands in the Rh-Catalyzed n-Regioselective Hydroformylation of Olefins(Washington, DC : ACS, 2016) Zhang, Baoxin; Jiao, Haijun; Michalik, Dirk; Kloß, Svenja; Deter, Lisa Marie; Selent, Detlef; Spannenberg, Anke; Franke, Robert; Börner, ArminThe stability of ligands and catalysts is an almost neglected issue in homogeneous catalysis, but it is crucial for successful application of this methodology in technical scale. We have studied the effect of water on phosphites, which are the most applied cocatalysts in the n-regioselective homogeneous Rh-catalyzed hydroformylation of olefins. The stability of the bidentate nonsymmetrical diphosphite L1, as well as its two monophosphite constituents L2 and L3, toward hydrolysis was investigated by means of in situ NMR spectroscopy under similar conditions as applied in industry. Hydrolysis pathways, intermediates, and kinetics were clarified. DFT calculations were used to support the experimentally found data. The acylphosphite unit L2, which reacts with water in an unselective manner, was proven to be much less stable than the phenolphosphite L3. The stability of the bidentate ligand L1 can be therefore mainly attributed to its phenolphosphite moiety. With an excess of water, the hydrolysis of L1 and L2 as well as their Rh-complexes is first-order with respect to the phosphite. Surprisingly, coordination to Rh significantly stabilizes the monodentate ligand L2, while in strong contrast, the bidentate ligand L1 decomposes faster in the Rh complex. NMR spectroscopy provided evidence for the existence of species from decomposition of phosphites, which can likewise coordinate as ligands to the metal. Electron-withdrawing groups in the periphery of the acylphosphite moiety decrease the stability of L1, whereas 3,5-disubstituted salicylic acid derivatives with bulky groups showed superior stability. These modifications of L1 also give rise to different catalytic performances in the n-regioselective hydroformylation of n-octenes and 2-pentene, from which the 3,5-di-t-butyl-substituted ligand offered a higher n-regioselectivity accompanied by a lowering of the reaction rate in comparison to the parent ligand L1.
- 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 adiponitrile with [Zr(C10H15)2([eta]2-Me3SiC2SiMe3)]. Intramolecular nitrile-nitrile couplings and deprotonation of the substrate produced the (1-imino-2-enimino)cyclopentane ligand, which functions as a five-membered bridge between the two metal atoms. The ZrIV atom exhibits a distorted tetrahedral coordination sphere defined by two pentamethylcyclopentadienyl ligands, by the imino unit of one (1-imino-2-enimino)cyclopentane and by the enimino unit of the second (1-imino-2-enimino)cyclopentane. The cyclopentane ring of the ligand shows an envelope conformation. The asymmetric unit contains one half of the complex and one half of the hexane solvent molecule, both being completed by the application of inversion symmetry. One of the pentamethylcyclopentadienyl 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 molecules are packed into rods extending along [100], with the solvent molecules located in between. The rods are arranged in a distorted hexagonal 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 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)°].