About the Influence of Geometrical Factors on Liquid Crystalline Properties—The Methylene Group as a Central Spacer Unit

Abstract

The preparation and liquid crystalline properties of four classes of substance with a central methylene spacer unit are described. As a result of our investigations, it is shown that a “one-atomic” central spacer, such as a methylene group, combined with a 1,4-cyclohexylene ring, contributes to the stabilization of the liquid crystalline state in the same way as a—(CH₂)₅—moiety.

Compounds with this new “crooked” central spacer of course exhibit lower clearing temperatures than compounds with ethylene (CH₂CH₂) spacers etc., but they demonstrate a new quality in relation to the influence of geometrical factors on liquid crystalline properties.

Key Words:

• geometry of LC-molecules
• mesogenic central methylene spacer
• mesogenic cyclohexane derivatives