On the solid polymorphs of the discotic mesogen hexa-octanoyloxytriphenylene
作者:
S. Zamir,
N. Spielberg,
H Zimmermann,
R. Poupko,
Z. Luz,
期刊:
Liquid Crystals
(Taylor Available online 1995)
卷期:
Volume 18,
issue 5
页码: 781-786
ISSN:0267-8292
年代: 1995
DOI:10.1080/02678299508036690
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
In an earlier study by van Heckeet al., it was shown that the discotic mesogen hexa-octanoyloxytriphenylene (HAT8) crystallizes in four different solid forms, depending on the thermal history of the sample. The present study is an attempt to characterize three of these solids in more detail using X-ray, carbon-13 and deuterium NMR techniques. It is shown that van Hecke's modificationIVis a metastable amorphic solid, while modificationsIIIandIIare highly ordered crystalline solids. Both are apparently monoclinic, but with different unit cell dimensions. In all solid phases, the triphenylene core is static on the NMR time-scale, but the side chains are disordered to different degrees in the different modifications. Further NMR studies on the discotic mesophase of HAT8 are also reported.
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