Low temperature enantiotropic nematic phases from V-shaped, shape-persistent molecules
A series of V-shaped, shape-persistent thiadiazole nematogens, based on an oligo(phenylene ethynylene) scaffold with ester groups connected via alkyloxy spacers, was efficiently prepared by a two-step procedure. Phase engineering results in an optimum of the mesophase range and low melting temperatu...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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Beilstein-Institut
2009-12-01
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| Series: | Beilstein Journal of Organic Chemistry |
| Subjects: | |
| Online Access: | https://doi.org/10.3762/bjoc.5.73 |
| _version_ | 1818946360269864960 |
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| author | Matthias Lehmann Jens Seltmann |
| author_facet | Matthias Lehmann Jens Seltmann |
| author_sort | Matthias Lehmann |
| collection | DOAJ |
| description | A series of V-shaped, shape-persistent thiadiazole nematogens, based on an oligo(phenylene ethynylene) scaffold with ester groups connected via alkyloxy spacers, was efficiently prepared by a two-step procedure. Phase engineering results in an optimum of the mesophase range and low melting temperature when the nematogens are desymmetrised with a butoxy and a heptyloxy spacer. The mesophases are enantiotropic and over the whole temperature range nematic. For the optimised mesogen structure, optical investigations by conoscopy monitored a uniaxial nematic phase upon cooling from the isotropic phase to room temperature (ΔT = 150 °C). X-ray studies on magnetic-field-aligned samples of this mesogen family revealed a general pattern, indicating the alignment of two molecular axes along individual directors in the magnetic field. These observations may be rationalised with larger assemblies of V-shaped molecules isotropically distributed around the direction of the magnetic field. |
| first_indexed | 2024-12-20T08:13:46Z |
| format | Article |
| id | doaj.art-9fbdc04b54cb4ef084d9c19a0d15bc19 |
| institution | Directory Open Access Journal |
| issn | 1860-5397 |
| language | English |
| last_indexed | 2024-12-20T08:13:46Z |
| publishDate | 2009-12-01 |
| publisher | Beilstein-Institut |
| record_format | Article |
| series | Beilstein Journal of Organic Chemistry |
| spelling | doaj.art-9fbdc04b54cb4ef084d9c19a0d15bc192022-12-21T19:47:11ZengBeilstein-InstitutBeilstein Journal of Organic Chemistry1860-53972009-12-01517310.3762/bjoc.5.731860-5397-5-73Low temperature enantiotropic nematic phases from V-shaped, shape-persistent moleculesMatthias Lehmann0Jens Seltmann1Institute of Chemistry, Chemnitz University of Technology, Straße der Nationen 62, 09111 Chemnitz, GermanyInstitute of Chemistry, Chemnitz University of Technology, Straße der Nationen 62, 09111 Chemnitz, GermanyA series of V-shaped, shape-persistent thiadiazole nematogens, based on an oligo(phenylene ethynylene) scaffold with ester groups connected via alkyloxy spacers, was efficiently prepared by a two-step procedure. Phase engineering results in an optimum of the mesophase range and low melting temperature when the nematogens are desymmetrised with a butoxy and a heptyloxy spacer. The mesophases are enantiotropic and over the whole temperature range nematic. For the optimised mesogen structure, optical investigations by conoscopy monitored a uniaxial nematic phase upon cooling from the isotropic phase to room temperature (ΔT = 150 °C). X-ray studies on magnetic-field-aligned samples of this mesogen family revealed a general pattern, indicating the alignment of two molecular axes along individual directors in the magnetic field. These observations may be rationalised with larger assemblies of V-shaped molecules isotropically distributed around the direction of the magnetic field.https://doi.org/10.3762/bjoc.5.73biaxial nematicsliquid crystalsphase engineeringthiadiazolesV-shaped mesogens |
| spellingShingle | Matthias Lehmann Jens Seltmann Low temperature enantiotropic nematic phases from V-shaped, shape-persistent molecules Beilstein Journal of Organic Chemistry biaxial nematics liquid crystals phase engineering thiadiazoles V-shaped mesogens |
| title | Low temperature enantiotropic nematic phases from V-shaped, shape-persistent molecules |
| title_full | Low temperature enantiotropic nematic phases from V-shaped, shape-persistent molecules |
| title_fullStr | Low temperature enantiotropic nematic phases from V-shaped, shape-persistent molecules |
| title_full_unstemmed | Low temperature enantiotropic nematic phases from V-shaped, shape-persistent molecules |
| title_short | Low temperature enantiotropic nematic phases from V-shaped, shape-persistent molecules |
| title_sort | low temperature enantiotropic nematic phases from v shaped shape persistent molecules |
| topic | biaxial nematics liquid crystals phase engineering thiadiazoles V-shaped mesogens |
| url | https://doi.org/10.3762/bjoc.5.73 |
| work_keys_str_mv | AT matthiaslehmann lowtemperatureenantiotropicnematicphasesfromvshapedshapepersistentmolecules AT jensseltmann lowtemperatureenantiotropicnematicphasesfromvshapedshapepersistentmolecules |