THE EFFECT OF THE POSITION OF LATERAL FLUORO-SUBSTITUENTS ON THE STABILITY OF THE S-STAR(C-ALPHA) AND S-STAR(CA) PHASES

被引:52
作者
FAYE, V [1 ]
ROUILLON, JC [1 ]
DESTRADE, C [1 ]
NGUYEN, HT [1 ]
机构
[1] CTR RECH PAUL PASCAL,F-33600 PESSAC,FRANCE
关键词
D O I
10.1080/02678299508036719
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
Four new chiral series with benzoate cores have been synthesized and characterized. The mesomorphic properties have been analysed by optical microscopy on the pure enantiomeric and the racemic compounds and on mixtures, by D.S.C. and by electro-optic measurements. Three of the series (hydrogenous, monofluoro-substituted ortho to the alkoxy chain, and difluoro-substituted) display a very rich polymorphism including S-A, S-C alpha* , S-C*, S-CFI* and S-CA*, phases, whereas the series monofluoro-substituted in the meta-position does not exhibit S-CFI*, and S-CA*, phases any more except for the dodecyloxy derivative, but gives a large enantiotropic S-C alpha*, phase. A comparison of these four series leads to a discussion about the effect of the transverse dipole moment on the existence of the S-CA*, phase.
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页码:47 / 56
页数:10
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