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Ionic liquid crystals with hemicyanine chromophores

Koen Binnemans, C Bex and Rik Van Deun UGent (1999) JOURNAL OF INCLUSION PHENOMENA AND MACROCYCLIC CHEMISTRY. 35(1-2). p.63-73
abstract
(E)-N-alkyl-4-(2-(4-dimethylaminophenyl)ethenyl) pyridinium bromides (hemicyanine bromides) with C-14, C-16 and C-18 straight alkyl chains are described. The thermal behaviour of these compounds was investigated by differential scanning calorimetry (DSC) and by optical microscopy. The textures observed in polarised light revealed that these compounds exhibit a smectic A mesophase. A focal-conic fan texture was observed, together with regions showing homeotropic alignment. The phase behaviour of the compound with the C(1)6 chain can be summarized as: Cr-1. 99 . Cr-2. 249 . SmA . 268 . I (dec.). The transition temperatures are rather independent of the length of the alkyl chain. The compounds have a strong tendency to supercool to a glassy mesophase. A structural model for the mesophase is proposed. The bromide anion of the hemicyanine bromides can be replaced by the bulky tetrakis(beta-diketonato)lanthanide(III) anion. As the beta-diketone, 2,4-pentanedione (acetylacetone, acac) and 1,3-diphenyl-1,3-propanedione (dibenzoylmethane, DBM) are chosen. None of the lanthanide complexes containing the hemicyanine chromophore shows a mesophase. The complexes either melt directly to an isotropic liquid, or decompose without melting.
Please use this url to cite or link to this publication:
author
organization
year
type
journalArticle (original)
publication status
published
subject
keyword
liquid crystals, hemicyanine, MONOLAYERS, DYES, OPTICAL-PROPERTIES, 2ND-HARMONIC GENERATION, RARE-EARTH COMPLEX, LANGMUIR-BLODGETT-FILM, glassy mesophase, metallomesogens, beta-diketone, rare earths, lanthanides
journal title
JOURNAL OF INCLUSION PHENOMENA AND MACROCYCLIC CHEMISTRY
J. Incl. Phenom. Macrocycl. Chem.
volume
35
issue
1-2
pages
63 - 73
conference name
1st International conference on Supramolecular Science and Technology
conference location
Zakopane, Poland
conference start
1998-09-27
conference end
1998-10-03
Web of Science type
Proceedings Paper
Web of Science id
000083282000008
ISSN
0923-0750
DOI
10.1023/A:1008146431142
language
English
UGent publication?
no
classification
A1
copyright statement
I have transferred the copyright for this publication to the publisher
id
1190450
handle
http://hdl.handle.net/1854/LU-1190450
date created
2011-03-16 16:13:27
date last changed
2011-05-05 16:38:57
@article{1190450,
  abstract     = {(E)-N-alkyl-4-(2-(4-dimethylaminophenyl)ethenyl) pyridinium bromides (hemicyanine bromides) with C-14, C-16 and C-18 straight alkyl chains are described. The thermal behaviour of these compounds was investigated by differential scanning calorimetry (DSC) and by optical microscopy. The textures observed in polarised light revealed that these compounds exhibit a smectic A mesophase. A focal-conic fan texture was observed, together with regions showing homeotropic alignment. The phase behaviour of the compound with the C(1)6 chain can be summarized as: Cr-1. 99 . Cr-2. 249 . SmA . 268 . I (dec.). The transition temperatures are rather independent of the length of the alkyl chain. The compounds have a strong tendency to supercool to a glassy mesophase. A structural model for the mesophase is proposed. The bromide anion of the hemicyanine bromides can be replaced by the bulky tetrakis(beta-diketonato)lanthanide(III) anion. As the beta-diketone, 2,4-pentanedione (acetylacetone, acac) and 1,3-diphenyl-1,3-propanedione (dibenzoylmethane, DBM) are chosen. None of the lanthanide complexes containing the hemicyanine chromophore shows a mesophase. The complexes either melt directly to an isotropic liquid, or decompose without melting.},
  author       = {Binnemans, Koen and Bex, C and Van Deun, Rik},
  issn         = {0923-0750},
  journal      = {JOURNAL OF INCLUSION PHENOMENA AND MACROCYCLIC CHEMISTRY},
  keyword      = {liquid crystals,hemicyanine,MONOLAYERS,DYES,OPTICAL-PROPERTIES,2ND-HARMONIC GENERATION,RARE-EARTH COMPLEX,LANGMUIR-BLODGETT-FILM,glassy mesophase,metallomesogens,beta-diketone,rare earths,lanthanides},
  language     = {eng},
  location     = {Zakopane, Poland},
  number       = {1-2},
  pages        = {63--73},
  title        = {Ionic liquid crystals with hemicyanine chromophores},
  url          = {http://dx.doi.org/10.1023/A:1008146431142},
  volume       = {35},
  year         = {1999},
}

Chicago
Binnemans, Koen, C Bex, and Rik Van Deun. 1999. “Ionic Liquid Crystals with Hemicyanine Chromophores.” Journal of Inclusion Phenomena and Macrocyclic Chemistry 35 (1-2): 63–73.
APA
Binnemans, Koen, Bex, C., & Van Deun, R. (1999). Ionic liquid crystals with hemicyanine chromophores. JOURNAL OF INCLUSION PHENOMENA AND MACROCYCLIC CHEMISTRY, 35(1-2), 63–73. Presented at the 1st International conference on Supramolecular Science and Technology.
Vancouver
1.
Binnemans K, Bex C, Van Deun R. Ionic liquid crystals with hemicyanine chromophores. JOURNAL OF INCLUSION PHENOMENA AND MACROCYCLIC CHEMISTRY. 1999;35(1-2):63–73.
MLA
Binnemans, Koen, C Bex, and Rik Van Deun. “Ionic Liquid Crystals with Hemicyanine Chromophores.” JOURNAL OF INCLUSION PHENOMENA AND MACROCYCLIC CHEMISTRY 35.1-2 (1999): 63–73. Print.