Columnar Mesomorphic Organizations in Cyclotriphosphazenes.
A synthetic strategy has been developed to prepare cyclotriphosphazenes that bear polycatenar aromatic esters as promesogenic units linked to phosphorus atoms. The microsegregation of the rigid and flexible parts of the system and the space-filling properties are the driving forces that determine th...
| Publicado en: | Journal of the American Chemical Society Vol. 127; no. 25; pp. 8994 - 9003 |
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| Autores principales: | , , , , , , , |
| Formato: | Artículo |
| Publicado: |
American Chemical Society
6/29/2005
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| Materias: | |
| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=17604818&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 17604818 longDbName: Humanities International Complete uiTag: AN controlInfo: bkinfo: jinfo: jid: 00027863 ACS jtl: Journal of the American Chemical Society issn: 00027863 maglogo: N pubinfo: dt: 6/29/2005 vid: 127 iid: 25 pid: 997 pub: American Chemical Society artinfo: ui: 17604818 10.1021/ja051042w ppf: 8994 ppct: 9 formats: tig: atl: Columnar Mesomorphic Organizations in Cyclotriphosphazenes. aug: au: Barberä, Joaquin Bardají, Manuel Jimënez, Josefina Laguna, Antonio Pilar Martínez, M. Oriol, Luis Luis Serrano, Josí Zaragozan, Irene affil: Polymer and Liquid Crystal Group, Departamento de Química Orgánica, Instituto de Ciencia de Materiales de Aragôn, Universidad de Zaragoza-C.S.I.C., 50009 Zaragoza, Spain. Departamento de Química lnorgánica, Instituto de Ciencia de Materiales de Aragôn, Universidad de Zaragoza-C.S.I.C., 50009 Zaragoza, Spain. su: Aromatic compounds Esters Phosphorus Molecules X-ray diffraction Organic compounds sug: subj: Aromatic compounds Esters Phosphorus Molecules X-ray diffraction Organic compounds ab: A synthetic strategy has been developed to prepare cyclotriphosphazenes that bear polycatenar aromatic esters as promesogenic units linked to phosphorus atoms. The microsegregation of the rigid and flexible parts of the system and the space-filling properties are the driving forces that determine the kind of mesomorphism exhibited by the organocyclotriphosphazenes. Mesogenic units that contain only one terminal alkyl chain give rise to calamitic mesomorphism, since the molecules are arranged to give a cylindrical superstructure with the aromatic promesogenic cores elongated in a manner approximately perpendicular to the cyclotriphosphazene ring. On the other hand, mesogenic units that contain three long terminal chains exhibit columnar mesophases. In this case, a discotic structure consisting of promesogenic cores arranged approximately parallel to the cyclotriphosphazene ring can explain the columnar organization. The X-ray diffraction patterns corresponding to the COlh mesophase of the cyclotriphosphazene with dodecyloxy chains (8) indicate the presence of helical ordering, which was confirmed for a homologous compound bearing stereogenic centers on two of the terminal chains (11). All of the synthesized phosphazenes show a high thermal stability. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2005 holdings: @attributes: islocal: N |
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