| Highly twisted helical polyacetylene with morphology free from the bundle of fibrils synthesized in chiral nematic liquid crystal reaction field. | |
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MedLine Citation:
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PMID: 17579404 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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We synthesized novel axially chiral binaphthyl derivatives with highly twisting powers by substituting phenylcyclohexyl (PCH) mesogenic moieties into 2,2' positions or 2,2',6,6' positions of binaphthyl rings. The di- and tetrasubstituted binaphthyl derivatives, abbreviated as D-1 and D-2, respectively, were adopted as chiral dopants to induce chiral nematic liquid crystals (N*-LCs) available for synthesis of helical polyacetylene. The helical twisting power (betaM) of D-2 was 449 microm(-1), which was ca. 2.6 times larger than that of D-1 (171 microm(-1)). We prepared two kinds of induced N*-LCs with 5 microm and 270 nm in helical pitch by adding the chiral dopants D-1 and D-2 into the host N-LCs, respectively. The helical polyacetylene synthesized in the N*-LC containing D-2 exhibited highly screwed fibrils, but not a bundle of fibrils. This result is in quite contrast to the usual fibril morphology, where the screwed fibrils are gathered to form the bundle of fibrils, as observed in the helical polyacetylene synthesized in the N*-LC containing a chiral dopant with moderate helical twisting power, such as D-1. It is of keen interest that the helical pitch (270 nm) of the N*-LC including D-2 is much smaller than the diameter (ca. 1 microm) of the bundle of fibrils, which should depress the formation of the bundle of fibrils. The morphology free from the bundle of fibrils might enable us to evaluate more precisely intrinsic electromagnetic properties of a single screwed fibril of helical polyacetylene. |
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Authors:
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Munju Goh; Mutsumasa Kyotani; Kazuo Akagi |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2007-06-19 |
Journal Detail:
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Title: Journal of the American Chemical Society Volume: 129 ISSN: 0002-7863 ISO Abbreviation: J. Am. Chem. Soc. Publication Date: 2007 Jul |
Date Detail:
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Created Date: 2007-07-03 Completed Date: 2007-09-05 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 7503056 Medline TA: J Am Chem Soc Country: United States |
Other Details:
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Languages: eng Pagination: 8519-27 Citation Subset: IM |
Affiliation:
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Department of Polymer Chemistry, Kyoto University, Katsura, Kyoto 615-8510, Japan. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Crystallization Magnetic Resonance Spectroscopy Microscopy Microscopy, Electron, Scanning Polyacetylenes / chemistry* Stereoisomerism |
| Chemical | |
Reg. No./Substance:
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25067-58-7/Polyacetylenes |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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