Induction of nematic cholesteric (N*) phases by charge transfer complexation of disc-shaped multiynes [1]
作者:
K. Praefcke,
D. Singer,
A. Eckert,
期刊:
Liquid Crystals
(Taylor Available online 1994)
卷期:
Volume 16,
issue 1
页码: 53-65
ISSN:0267-8292
年代: 1994
DOI:10.1080/02678299408036520
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
Based on charge transfer interactions with the (chiral) electron acceptor (-)-2-(2,4,5,7-tetranitro-9-fluorenylidenaminooxy)propionic acid ((-)-TAPA), our easily accessible disc-shaped electron rich multiynes (for example,1and2) give rise to two types of cholesteric nematic phases. Thus, thebinarymixture of the nematic discotic (ND) pentakis-(4-methylphenylethynyl)phenyl hexadecyl ether (2) with (-)-TAPA exhibits its twisted variant (N*D). Likewise, but now in aternarymixture, the homologue1—peripherically unsubstituted andnon-mesogenic—with the two electron acceptors (-)- TAPA and 2,4,7-trinitrofluorenone—both alsonon-liquid crystalline—shows cholesteric nematic properties, most probably however of a columnar type (N*C). First results concerning these charge transfer induced cholesteric-nematic properties, including phase diagrams and the helical twist of the two systems presented here, are discussed on the basis of data obtained by polarizing microscopy and differential scanning calorimetry.
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