| 1. |
- Besnard, Céline, et al.
(författare)
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Azinyl sulfides. LXXXI. 14-Phenyl-7-thiapyrano[2,3-c;6,5-c ']diquinoline-14-carbonitrile
- 2005
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Ingår i: Acta Crystallographica. Section C: Crystal Structure Communications. - 0108-2701. ; 61:Pt 6, s. 377-379
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Tidskriftsartikel (refereegranskat)abstract
- The molecules of the title compound, C26H15N3S, have a pentacyclic ring system which is almost planar, with the central ring in a flattened boat conformation. The folding angle between the two quinoline rings is 6.75 ( 7)degrees. The 14- phenyl substituent is in a quasi- axial conformation, while the 14-cyano substituent is in a quasi- equatorial conformation with respect to the thiopyran ring. The S center dot center dot center dot C - C-phenyl and S center dot center dot center dot C - C-CN angles are 116.8 ( 2) and 129.3 ( 2) degrees, respectively. The plane of the phenyl group is nearly coplanar with the plane bisecting the dihedral angle of the pentacyclic ring system.
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| 2. |
- Besnard, Céline, et al.
(författare)
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Azinyl sulfides - Part LXVIII - X-ray structure of 14-phenyldiquino[3,4 b;4 ',3 '-e][1,4]thiazine
- 2005
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Ingår i: Journal of Chemical Crystallography. - : Springer Science and Business Media LLC. - 1074-1542 .- 1572-8854. ; 35:9, s. 731-736
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Tidskriftsartikel (refereegranskat)abstract
- The title compound 1 (C24H15N3S) crystallizes in an orthorhombic unit cell, with a = 8.2355(3), b = 19.1499(8), and c = 11.3520(5) angstrom, Z = 2, and space group Pnma. The pentacyclic ring system is folded mainly along the S-N(2) axis and slightly along the C(3)-C(4) and C(3')-C(4') axes. The butterfly folding angle between the two quinoline planes is 48.96(3)degrees and the angle between the planes of the two halves of the thiazine ring is 43.46(7)degrees. The central thiazine ring is in a boat conformation. The phenyl substituent is unexpectedly in an axial location with respect to the thiazine ring with the C-N center dot center dot center dot S angle of 114.0(1)degrees and it is perpendicular to the bisecting plane of the pentacyclic ring system.
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| 3. |
- Besnard, Céline, et al.
(författare)
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Diquino[3,4-b;4 ',3 '-e][1,4] dithiine
- 2006
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Ingår i: Acta Crystallographica Section E: Structure Reports Online. - 1600-5368. ; 62:4, s. 1333-1335
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Tidskriftsartikel (refereegranskat)abstract
- In the title compound, C18H10N2S2, a crystallographic mirror plane passes through the two S atoms. The pentacyclic ring system is folded along the S-S vector and the central dithiine ring adopts a boat conformation.
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| 4. |
- Besnard, Céline, et al.
(författare)
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Diquino[4,3-b;3 ',4 '-e][1,4]thiaselenine
- 2006
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Ingår i: Acta Crystallographica Section E: Structure Reports Online. - 1600-5368. ; 62:8, s. 3203-3205
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Tidskriftsartikel (refereegranskat)abstract
- The title compound, C18H10N2SSe, is a pentacyclic ring system folded along the S center dot center dot center dot Se vector. The central thiaselenine ring adopts a boat conformation and the two halves of the molecule are related by a crystallographic mirror plane.
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| 5. |
- Besnard, Céline, et al.
(författare)
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Re4As6S3, a thio-spinel-related cluster system.
- 2003
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Ingår i: Journal of Solid State Chemistry. - 0022-4596. ; 172:2, s. 446-450
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Tidskriftsartikel (refereegranskat)abstract
- We have synthesized a new compound with formula Re4As6S3 and characterized its crystal structure by Rietveld powder diffraction methods. Re4As6S3 crystallizes in an face-centered cubic unit cell, space group F (4) over bar 3m (no. 216), with lattice constant a = 9.8608(1) Angstrom and Z = 4. The rhenium atoms form tetrahedral clusters linked via tetrahedral arsenic clusters to produce an NaCl-type arrangement. The oxidation state of rhenium is IV and the number of electrons shared by the rhenium atoms in the cluster is 12. The structure is based on an ordered defect thio-spinel A((1-x))B(2)X(4) where the B-type atoms form tetrahedral clusters. (C) 2003 Elsevier Science (USA). All rights reserved.
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| 6. |
- Chi, X, et al.
(författare)
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Structure and transport properties of the charge-transfer salt coronene - TCNQ
- 2004
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Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 16:26, s. 5751-5755
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Tidskriftsartikel (refereegranskat)abstract
- Coronene is a highly symmetric organic molecule whose molecular structure resembles a fragment of graphite. We have crystallized a charge-transfer complex based on coronene and TCNQ, and present crystal structure and transport properties. The complex adopts alternate stacking between coronene and TCNQ and the charge-transfer was estimated to be of the order of 0.3 by the structure and IR analysis of TCNQ. This degree of charge-transfer is larger than those of other hydrocarbon based charge-transfer complexes reported. We find semiconductor behavior with an optical gap of 1.55 eV and a transport gap of 0.49 eV. The Child's law mobility is estimated to be 0.3 cm(2)/Vs-this alone, with the small tran-sport gap suggests this compound might be attractive for device applications.
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| 7. |
- Gozar, A, et al.
(författare)
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Inhomogeneous CuO6 tilt distribution and charge-spin correlations in La2-x-yNdySrxCuO4 around the commensurate hole concentration
- 2003
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Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 68:5, s. 1-052511
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Tidskriftsartikel (refereegranskat)abstract
- Phononic and magnetic Raman scattering are studied in La2-x-yNdySrxCuO4 with three doping concentrations: x1/8, y = 0; x1/8, y = 0.4; and x = 0.01, y = 0. We observe strong disorder in the tilt pattern of the CuO6 octahedra in both the orthorhombic and tetragonal phases that persist down to 10 K and are coupled to bond disorder in the cation layers around 1/8 doping independent of Nd concentration. The weak magnitude of existing charge-spin modulations in the Nd-doped structure does not allow us to detect the specific Raman signatures of lattice dynamics or two-magnon scattering around 2200 cm–1. ©2003 The American Physical Society
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| 8. |
- Haddon, RC, et al.
(författare)
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Band electronic structure of one- and two-dimensional pentacene molecular crystals
- 2002
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Ingår i: The Journal of Physical Chemistry Part B. - : American Chemical Society (ACS). - 1520-5207 .- 1520-6106. ; 106:33, s. 8288-8292
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Tidskriftsartikel (refereegranskat)abstract
- We report EHT calculations of the band electronic structure of substituted pentacene derivatives and the polymorphs of the parent compound. The results show that there are wide disparities among the bandwidths and electronic dimensionalities of these compounds. The parent pentacene polymorphs are 2-dimensional in their band electronic structure with moderate dispersions; the bandwidths in the 14.1 Angstrom d-spacing polymorph are noticeably larger than for the 14.5 Angstrom d-spacing polymorph, reported by Campbell. Whereas the parent pentacene polymorphs adopt the well-known herringbone packing, the new, substituted pentacenes are noticeably different in their solid state structures and this is reflected in the band electronic structures. TMS adopts a highly 1-dimensional structure that leads to a large bandwidth along the stacking direction; TIPS also adopts a stacked structure, but because the molecules are laterally interleaved in the fashion of bricks in a wall, this compound is strongly 2-dimensional.
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| 9. |
- Krieger, Ulrich K., et al.
(författare)
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A reference data set for validating vapor pressure measurement techniques : homologous series of polyethylene glycols
- 2018
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Ingår i: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 11:1, s. 49-63
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Tidskriftsartikel (refereegranskat)abstract
- To predict atmospheric partitioning of organic compounds between gas and aerosol particle phase based on explicit models for gas phase chemistry, saturation vapor pressures of the compounds need to be estimated. Estimation methods based on functional group contributions require training sets of compounds with well-established saturation vapor pressures. However, vapor pressures of semivolatile and low-volatility organic molecules at atmospheric temperatures reported in the literature often differ by several orders of magnitude between measurement techniques. These discrepancies exceed the stated uncertainty of each technique which is generally reported to be smaller than a factor of 2. At present, there is no general reference technique for measuring saturation vapor pressures of atmospherically relevant compounds with low vapor pressures at atmospheric temperatures. To address this problem, we measured vapor pressures with different techniques over a wide temperature range for intercomparison and to establish a reliable training set. We determined saturation vapor pressures for the homologous series of polyethylene glycols (H-(O-CH2-CH2)(n)-OH) for n = 3 to n = 8 ranging in vapor pressure at 298 K from 10(-7) to 5 x 10(-2) Pa and compare them with quantum chemistry calculations. Such a homologous series provides a reference set that covers several orders of magnitude in saturation vapor pressure, allowing a critical assessment of the lower limits of detection of vapor pressures for the different techniques as well as permitting the identification of potential sources of systematic error. Also, internal consistency within the series allows outlying data to be rejected more easily. Most of the measured vapor pressures agreed within the stated uncertainty range. Deviations mostly occurred for vapor pressure values approaching the lower detection limit of a technique. The good agreement between the measurement techniques (some of which are sensitive to the mass accommodation coefficient and some not) suggests that the mass accommodation coefficients of the studied compounds are close to unity. The quantum chemistry calculations were about 1 order of magnitude higher than the measurements. We find that extrapolation of vapor pressures from elevated to atmospheric temperatures is permissible over a range of about 100 K for these compounds, suggesting that measurements should be performed best at temperatures yielding the highest-accuracy data, allowing subsequent extrapolation to atmospheric temperatures.
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| 10. |
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