2-(4-Alkylphenyl)-5-(alkenyloxy)pyrimidines: Synthesis, liquid crystal transition temperatures and some physical properties
作者:
S.M. Kelly,
J. Fünfschilling,
A. Villiger,
期刊:
Liquid Crystals
(Taylor Available online 1994)
卷期:
Volume 16,
issue 5
页码: 813-829
ISSN:0267-8292
年代: 1994
DOI:10.1080/02678299408027852
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
We have recently reported the introduction of a carbon-carbon double bond into a wide variety of 5-n-alkyl-2-(4-n-alkoxyphenyl)pyrimidines to produce the corresponding alkenyloxy derivatives. The position and nature (E/Z) of the double bond were varied systematically and the effect on the liquid crystal transition temperatures studied. The position and nature (E/Z) of the double bond changed the conformation of the alkenyloxy chain substantially. This resulted in higher smectic C and nematic transition temperatures for compounds with atrans-double bond (E) at an even number of carbon atoms from the molecular core. Significantly lower transition temperatures (including the melting point) were observed for materials with acis-double bond (Z) at an odd number of carbon atoms from the molecular core. We have now performed the same operation on the related 2-(4-n-alkylphenyl)-5-n-alkoxypyrimidines to produce the corresponding alkenyloxy derivatives. An interesting feature of the new results is thehighmelting points of thetrans-substituted materials and thelowmelting points of the terminally substituted compounds. The smectic C transition temperatures of both series are high. No nematic phases could be observed. However, in admixture with other smectic C components, the new compounds lead to surprisingly fast switching times, high smectic C transition temperatures and low melting points/crystallization temperatures in experimental mixtures designed for electro-optic display devices based on ferroelectric effects.
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