- Conformation and packing of odd-numbered α-oligothiophenes in single crystals
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X-ray single crystal analyses revealed the molecular geometry and molecular packing of odd-numbered α-oligothiophenes (septithiophene, quinquethiophene and terthiophene) in single crystals prepared by sublimation. Septithiophene crystallizes into triclinic, which is in contrast to the monoclinic packing of even-numbered oligomers. The molecular arrangement of septithiophene in a single crystal resembles that reported for even-numbered oligomers, while the molecules take a more random conformation: only one of the two terminal thienyl rings exhibits disorder and significant torsion from the conjugated plane. The X-ray diffraction data of a quinquethiophene single crystal suggest that the molecule with one of the two different orientations randomly occupies each site.
- Azumi, Reiko,Goto, Midori,Honda, Kazumasa,Matsumoto, Mutsuyoshi
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- PREPARATION OF α-QUINQUE- AND α-SEPTITHIOPHENES AND THEIR POSITIONAL ISOMERS
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α-Quinque- and α-septithiophenes were synthesized in four steps starting from α-bi- and α-terthiophenes, respectively.One of positional isomers of each oligothiophene described above is also synthesized.
- Nakayama, Juzo,Nakamura, Yoichi,Murabayashi, Shigeru,Hoshino, Masamatsu
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p. 939 - 942
(2007/10/02)
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- Synthesis of α-Thiophene Oligomers via 1,3-Butadiynes
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Individual oligomers possessing thiophenes linked by their 2- and 5-positions are conveniently prepared via 1,3-butadiynes.These can be prepared in good yield by the Glaser symmetrical coupling of thienylacetylenes.Following the cyclization of the 1,3-butadiyne unit into a thiophene with sodium sulfide, an oligomer possessing an odd number of thiophene rings is obtained.Oligomers with an even number of rings are accessible from unsymmetrical butadiynes obtained either by the Cadiot-Chodkiewicz procedure, utilizing an odd and an even precursor, or by an organoborane co upling procedure.
- Kagan, Jacques,Arora, Sudershan K.
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p. 4317 - 4320
(2007/10/02)
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