| 1. |
- Besnard, Céline, et al.
(författare)
-
Azinyl sulfides. LXXXI. 14-Phenyl-7-thiapyrano[2,3-c;6,5-c ']diquinoline-14-carbonitrile
- 2005
-
Ingår i: Acta Crystallographica. Section C: Crystal Structure Communications. - 0108-2701. ; 61:Pt 6, s. 377-379
-
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.
|
|
| 2. |
- Besnard, Céline, et al.
(författare)
-
Azinyl sulfides - Part LXVIII - X-ray structure of 14-phenyldiquino[3,4 b;4 ',3 '-e][1,4]thiazine
- 2005
-
Ingår i: Journal of Chemical Crystallography. - : Springer Science and Business Media LLC. - 1074-1542 .- 1572-8854. ; 35:9, s. 731-736
-
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.
|
|
| 3. |
- Besnard, Céline
(författare)
-
Crystallographic Studies of Ternary Chalcogenides and Organic Semiconductors
- 2004
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- X-ray diffraction methods have been used to study the crystal structure of different compounds, both organic and inorganic. The inorganic compounds were all synthesized by solid state reactions. A new compound, Re4As6S3, was synthesized and its structure was solved by Rietveld methods. Re4As6S3 is a cluster compound described by a rock-salt-type arrangement of ReAsS3- and As5- clusters. This structure is related to thiospinel with space-group F43m. In a further search for related systems, new intercalation compounds based on NbS2 and Al or Zn were found. The new compound with approximate stoichiometry Zn1/3NbS2 consists of layers of trigonal prismatic NbS6 with inclusion of Zn in the octahedral sites between these layers. The inclusion of yttrium in the antiferromagnet manganese telluride (MnTe) was observed, and magnetic measurements indicate strong antiferromagnetic interactions between unpaired spins created by the inclusion of yttrium. Single-crystal diffraction studies of organic semiconductors were carried out on crystals grown as part of a collaborative research project between Bell Laboratories (USA), Columbia University (USA) and the medical University of Silesia (Poland). The aim of this project is to better understand electronic charge transport in organic semiconductors. The crystal structures of two molecules with formula C42H30 and C42H26 that crystallized during the growth of rubrene (C42H28) crystals by vapour phase methods, were studied. The influence of substituents on molecular packing and hence on the charge transport was examined in different crystal structures of halogen substituted tetracene and hexacene-quinone. Finally the crystal structures of four quinoline and thiazine derivatives related to pentacene were studied. Unlike pentacene which is flat, all these molecules were butterfly molecules with five fused rings. Here, substituents strongly influence not only the packing of the molecules but also the butterfly angle.
|
|
| 4. |
- Besnard, Céline, et al.
(författare)
-
Diquino[3,4-b;4 ',3 '-e][1,4] dithiine
- 2006
-
Ingår i: Acta Crystallographica Section E: Structure Reports Online. - 1600-5368. ; 62:4, s. 1333-1335
-
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.
|
|
| 5. |
- Besnard, Céline, et al.
(författare)
-
Diquino[4,3-b;3 ',4 '-e][1,4]thiaselenine
- 2006
-
Ingår i: Acta Crystallographica Section E: Structure Reports Online. - 1600-5368. ; 62:8, s. 3203-3205
-
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.
|
|
| 6. |
- Besnard, Céline, et al.
(författare)
-
Re4As6S3, a thio-spinel-related cluster system.
- 2003
-
Ingår i: Journal of Solid State Chemistry. - 0022-4596. ; 172:2, s. 446-450
-
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.
|
|
| 7. |
- Chi, X, et al.
(författare)
-
Structure and transport properties of the charge-transfer salt coronene - TCNQ
- 2004
-
Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 16:26, s. 5751-5755
-
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.
|
|
| 8. |
- Clement, Yves, et al.
(författare)
-
Evolutionary forces affecting synonymous variations in plant genomes
- 2017
-
Ingår i: PLOS Genetics. - : PUBLIC LIBRARY SCIENCE. - 1553-7390 .- 1553-7404. ; 13:5
-
Tidskriftsartikel (refereegranskat)abstract
- Base composition is highly variable among and within plant genomes, especially at third codon positions, ranging from GC-poor and homogeneous species to GC-rich and highly heterogeneous ones (particularly Monocots). Consequently, synonymous codon usage is biased in most species, even when base composition is relatively homogeneous. The causes of these variations are still under debate, with three main forces being possibly involved: mutational bias, selection and GC-biased gene conversion (gBGC). So far, both selection and gBGC have been detected in some species but how their relative strength varies among and within species remains unclear. Population genetics approaches allow to jointly estimating the intensity of selection, gBGC and mutational bias. We extended a recently developed method and applied it to a large population genomic dataset based on transcriptome sequencing of 11 angiosperm species spread across the phylogeny. We found that at synonymous positions, base composition is far from mutation-drift equilibrium in most genomes and that gBGC is a widespread and stronger process than selection. gBGC could strongly contribute to base composition variation among plant species, implying that it should be taken into account in plant genome analyses, especially for GC-rich ones.
|
|
| 9. |
|
|
| 10. |
- Zeis, R, et al.
(författare)
-
Field effect studies on rubrene and impurities of rubrene
- 2006
-
Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 18:2, s. 244-248
-
Tidskriftsartikel (refereegranskat)abstract
- Rubrene single crystals have been grown by a vapor-phase process. Two additional compounds that contaminate rubrene have been identified and their structures determined. Single crystals of rubrene show excellent crystallinity and very small rocking curve width. Field effect transistors based on pure rubrene single crystals with colloidal graphite electrodes and Parylene as a dielectric demonstrate a maximal mobility of 13 cm(2)/Vs with strong anisotropy. The mobility increases very slightly with cooling, but decreases significantly at low temperatures.
|
|
