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- ItemElectronic materials with a wide band gap: Recent developments(Chester : International Union of Crystallography, 2014) Klimm, D.The development of semiconductor electronics is reviewed briefly, beginning with the development of germanium devices (band gap E g = 0.66 eV) after World War II. A tendency towards alternative materials with wider band gaps quickly became apparent, starting with silicon (E g = 1.12 eV). This improved the signal-to-noise ratio for classical electronic applications. Both semiconductors have a tetrahedral coordination, and by isoelectronic alternative replacement of Ge or Si with carbon or various anions and cations, other semiconductors with wider E g were obtained. These are transparent to visible light and belong to the group of wide band gap semiconductors. Nowadays, some nitrides, especially GaN and AlN, are the most important materials for optical emission in the ultraviolet and blue regions. Oxide crystals, such as ZnO and β-Ga2O3, offer similarly good electronic properties but still suffer from significant difficulties in obtaining stable and technologically adequate p-type conductivity.
- 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.
- Item(μ3-Hydrido)[μ3-2-(trimethylsilyl) ethylidyne-κ3C1:C1:C1] tetrakis[(η5-cyclopentadienyl)cobalt(II)](Chester : International Union of Crystallography, 2013) Haehnel, M.; Spannenberg, A.; Rosenthal, U.In the title compound, [Co4(C5H5) 4(μ3-CCH2SiMe3)(μ3-H)], the Co atoms form a distorted tetrahedron with the ethylidyne moiety bridging three of the Co atoms as well as the hydrido ligand also bridging three of the Co atoms. The Co-Co bond lengths in the Co4tetrahedron vary from 2.3844 (4) to 2.4608 (4) Å. Each Co atom is additionally η5-bonded to a cyclopentadienyl (Cp) anion.
- Item2,6-Bis[(S)-4-benzyl-4,5-dihydro-1,3-oxazol-2-yl]pyridine(Chester : International Union of Crystallography, 2011) Möller, K.; Junge, K.; Spannenberg, A.; Beller, M.The commercially available title compound, C25H 23N3O2, has been known since 1993 [Nesper et al. (1993). Helv. Chim. Acta, 76, 2239-2249], but has not been structurally characterized until now. In the free ligand, the N atoms of both oxazoline rings point in opposite directions. The phenyl rings make dihedral angles of 30.56 (5) and 84.57 (3)° with the pyridine ring and 72.85 (3)° with each other.
- Item[1-Dimethylsilyl-2-phenyl-3-(η5-tetramethylcyclopentadienyl) prop-1-en-1-ylκC1](n5-pentamethylcyclopentadienyl)- titanium(III)(Chester : International Union of Crystallography, 2009) Lamač, M.; Spannenberg, A.; Arndt, P.; Rosenthal, U.The title compound, [Ti(C10H15)(C20H 26Si)], was obtained from the reaction of [Ti{5: 1-C5Me4(CH2)}(5-C 5Me5)] with the alkynylsilane PhC2SiMe 2H. The complex crystallizes with two independent mol-ecules in the asymmetric unit, which differ in the conformation of the propenyl unit, resulting in their having opposite helicity. No inter-molecular inter-actions or inter-actions involving the Si- H bond are present. The observed geometrical parameters are unexceptional compared to known structures of the same type.
- ItemTetracarbonyl[bis(diphenylphosphanyl)-tetramethyldisiloxane- κ 2 P,P′]chromium(0)(Chester : International Union of Crystallography, 2012) Peulecke, N.; Müller, B.H.; Spannenberg, A.; Rosenthal, U.The title compound, [Cr(C 28H 32OP 2Si 2)(CO) 4], was obtained by the ligand-exchange reaction of Cr(CO) 6 with (Ph 2PSiMe 2) 2O in refluxing toluene. The CrC 4P 2 coordination geometry is distorted octa-hedral, with a P - Cr - P bite angle of 99.22 (4)°.
- ItemIodidobis(≠5-penta-methyl-cyclo-penta-dien-yl)titanium(III)(Chester : International Union of Crystallography, 2010) Kessler, M.; Spannenberg, A.; Rosenthal, U.In the title complex mol-ecule, [Ti(C10H15) 2I], the paramagnetic Ti(III) atom is coordinated by two penta-methyl-cyclo-penta-dienyl (Cp*) ligands and one iodide ligand. The two Cp*ligands are in a staggered orientation. The coordination geometry at the titanium atom can be described as distorted trigonal-planar.
- Item{2-[Bis(2,4-di-tert-butylphenoxy)-phosphanyloxy-κP]-3, 5-di-tert-butylphenyl-κC 1}[(1,2,5,6-η)-cycloocta-1,5-diene] rhodium(I) toluene monosolvate(Chester : International Union of Crystallography, 2012) Selent, D.; Spannenberg, A.; Börner, A.The reaction of (η 3-allyl)[(1,2,5,6-η)-cycloocta-1,5- diene]rhodium(I) with tris-(2,4-di-tert-butylphenyl)phosphite in toluene produces the title compound, [Rh(C 42H 62O 3P)(C 8H 12)]·C 7H 8, by spontaneous metallation at one of the nonsubstituted phenyl ortho-C atoms of the phosphite molecule. The coordination geometry at the Rh I ion is distorted squareplanar. The toluene solvent molecule is disordered over two different orientations, with site-occupation factors of 0.810 (2) and 0.190 (2).
- ItemTri-tert-butylphosphonium hydroxytris-(pentafluorophenyl)borate(Chester : International Union of Crystallography, 2012) Klahn, M.; Spannenberg, A.; Rosenthal, U.The ionic title compound, C12H28P+· C18HBF15O-, was obtained by the stoichiometric reaction of tBu3P, B(C6F5) 3 and water in toluene. A weak P - H⋯O hydrogen bond is observed in the crystal structure.
- Item(η6-Benzene)dichlorido(chlorodicyclohexylphosphane-κp) ruthenium(II) chloroform monosolvate(Chester : International Union of Crystallography, 2014) Gowrisankar, S.; Neumann, H.; Spannenberg, A.; Beller, M.The title compound, [RuN4(-6-C6H6) (C12H22ClP)]-CHCl3, was prepared by reaction of [RuN 4(-6-C6H6)]2 with chlorodicyclohexyl phosphane in CHCl3 at 323 K under argon. The RuII atom is surrounded by one arene ligand, two Cl atoms and a phosphane ligand in a piano-stool geometry. The phosphane ligand is linked by the P atom, with an Ru-P bond length of 2.3247 (4) Å. Both cyclohexyl rings at the P atom adopt a chair conformation. In the crystal, the RuII complex molecule and the chloroform solvent molecule are linked by a bifurcated C-H⋯(Cl,Cl) hydrogen bond. Intramolecular C-H⋯Cl hydrogen bonds are also observed.