An old dog with new tricks : schiff bases for liquid crystals materials based on isoxazolines and isoxazoles
Autor(a) principal: | |
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Data de Publicação: | 2016 |
Outros Autores: | |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UFRGS |
Texto Completo: | http://hdl.handle.net/10183/148207 |
Resumo: | Schiff bases are in action again showing an exuberant mesophase range despite their chemical and thermal weakness. Two series of Schiff bases (SB), based on isoxazolines 9 a–f and isoxazoles 10 a–f, are described. 9 a–f were synthesized by a [3+2] cycloaddition 1,3-dipolar of arylnitrile oxide from p-nitrobenzaldehyde (1) and alkenes. And, subsequently oxidized to 10 a–f by MnO2. The isoxazolines and isoxazoles thus obtained were reduced to aniline derivatives and condensed with appropriated arylaldehydes. The SBs series isoxazolines 9 a–f presented a narrow mesophase range, while SBs series isoxazoles 10 a–f showed a large mesophase range. Nematic mesophase was observed for SBs with short and non-polar groups, while SmA and SmC mesophase for SBs with long and more polar terminal groups. The stability of the SBs is also dependent on the clearing temperature. For 10 a–f with high clearing temperature, decomposition induced by heat was observed during the first cycle of heating and in solutions of CDCl3. Series 9 a–f was more resistant to the thermal decomposition. |
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Fritsch, LumaMerlo, Aloir Antonio2016-09-16T02:13:55Z20162365-6549http://hdl.handle.net/10183/148207001001764Schiff bases are in action again showing an exuberant mesophase range despite their chemical and thermal weakness. Two series of Schiff bases (SB), based on isoxazolines 9 a–f and isoxazoles 10 a–f, are described. 9 a–f were synthesized by a [3+2] cycloaddition 1,3-dipolar of arylnitrile oxide from p-nitrobenzaldehyde (1) and alkenes. And, subsequently oxidized to 10 a–f by MnO2. The isoxazolines and isoxazoles thus obtained were reduced to aniline derivatives and condensed with appropriated arylaldehydes. The SBs series isoxazolines 9 a–f presented a narrow mesophase range, while SBs series isoxazoles 10 a–f showed a large mesophase range. Nematic mesophase was observed for SBs with short and non-polar groups, while SmA and SmC mesophase for SBs with long and more polar terminal groups. The stability of the SBs is also dependent on the clearing temperature. For 10 a–f with high clearing temperature, decomposition induced by heat was observed during the first cycle of heating and in solutions of CDCl3. Series 9 a–f was more resistant to the thermal decomposition.application/pdfengChemistrySelect. Weinheim, Alemanha. Vol. 1, no. 1 (Jan. 2016), p. 23-30Cristais líquidosIminasCompostos orgânicos : SínteseBase de SchiffIsoxazolinasIsoxazolesAn old dog with new tricks : schiff bases for liquid crystals materials based on isoxazolines and isoxazolesEstrangeiroinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFRGSinstname:Universidade Federal do Rio Grande do Sul (UFRGS)instacron:UFRGSORIGINAL001001764.pdf001001764.pdfTexto completo (inglês)application/pdf6522949http://www.lume.ufrgs.br/bitstream/10183/148207/1/001001764.pdfc3abb5b138aa6ef9178c7bab3745b609MD51TEXT001001764.pdf.txt001001764.pdf.txtExtracted Texttext/plain63705http://www.lume.ufrgs.br/bitstream/10183/148207/2/001001764.pdf.txtba1b48743dc52de168964bf08d45d9c6MD52THUMBNAIL001001764.pdf.jpg001001764.pdf.jpgGenerated Thumbnailimage/jpeg1997http://www.lume.ufrgs.br/bitstream/10183/148207/3/001001764.pdf.jpg5e00f0405b1f0d21778f4e7313d5fc54MD5310183/1482072018-10-29 08:53:21.677oai:www.lume.ufrgs.br:10183/148207Repositório de PublicaçõesPUBhttps://lume.ufrgs.br/oai/requestopendoar:2018-10-29T11:53:21Repositório Institucional da UFRGS - Universidade Federal do Rio Grande do Sul (UFRGS)false |
dc.title.pt_BR.fl_str_mv |
An old dog with new tricks : schiff bases for liquid crystals materials based on isoxazolines and isoxazoles |
title |
An old dog with new tricks : schiff bases for liquid crystals materials based on isoxazolines and isoxazoles |
spellingShingle |
An old dog with new tricks : schiff bases for liquid crystals materials based on isoxazolines and isoxazoles Fritsch, Luma Cristais líquidos Iminas Compostos orgânicos : Síntese Base de Schiff Isoxazolinas Isoxazoles |
title_short |
An old dog with new tricks : schiff bases for liquid crystals materials based on isoxazolines and isoxazoles |
title_full |
An old dog with new tricks : schiff bases for liquid crystals materials based on isoxazolines and isoxazoles |
title_fullStr |
An old dog with new tricks : schiff bases for liquid crystals materials based on isoxazolines and isoxazoles |
title_full_unstemmed |
An old dog with new tricks : schiff bases for liquid crystals materials based on isoxazolines and isoxazoles |
title_sort |
An old dog with new tricks : schiff bases for liquid crystals materials based on isoxazolines and isoxazoles |
author |
Fritsch, Luma |
author_facet |
Fritsch, Luma Merlo, Aloir Antonio |
author_role |
author |
author2 |
Merlo, Aloir Antonio |
author2_role |
author |
dc.contributor.author.fl_str_mv |
Fritsch, Luma Merlo, Aloir Antonio |
dc.subject.por.fl_str_mv |
Cristais líquidos Iminas Compostos orgânicos : Síntese Base de Schiff Isoxazolinas Isoxazoles |
topic |
Cristais líquidos Iminas Compostos orgânicos : Síntese Base de Schiff Isoxazolinas Isoxazoles |
description |
Schiff bases are in action again showing an exuberant mesophase range despite their chemical and thermal weakness. Two series of Schiff bases (SB), based on isoxazolines 9 a–f and isoxazoles 10 a–f, are described. 9 a–f were synthesized by a [3+2] cycloaddition 1,3-dipolar of arylnitrile oxide from p-nitrobenzaldehyde (1) and alkenes. And, subsequently oxidized to 10 a–f by MnO2. The isoxazolines and isoxazoles thus obtained were reduced to aniline derivatives and condensed with appropriated arylaldehydes. The SBs series isoxazolines 9 a–f presented a narrow mesophase range, while SBs series isoxazoles 10 a–f showed a large mesophase range. Nematic mesophase was observed for SBs with short and non-polar groups, while SmA and SmC mesophase for SBs with long and more polar terminal groups. The stability of the SBs is also dependent on the clearing temperature. For 10 a–f with high clearing temperature, decomposition induced by heat was observed during the first cycle of heating and in solutions of CDCl3. Series 9 a–f was more resistant to the thermal decomposition. |
publishDate |
2016 |
dc.date.accessioned.fl_str_mv |
2016-09-16T02:13:55Z |
dc.date.issued.fl_str_mv |
2016 |
dc.type.driver.fl_str_mv |
Estrangeiro info:eu-repo/semantics/article |
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info:eu-repo/semantics/publishedVersion |
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publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10183/148207 |
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2365-6549 |
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001001764 |
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http://hdl.handle.net/10183/148207 |
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eng |
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eng |
dc.relation.ispartof.pt_BR.fl_str_mv |
ChemistrySelect. Weinheim, Alemanha. Vol. 1, no. 1 (Jan. 2016), p. 23-30 |
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info:eu-repo/semantics/openAccess |
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openAccess |
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application/pdf |
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