Mesomorphic Behavior of Compounds Incorporating One-Unit Linking Groups

Abstract

4,4′-Bis[4-(4-alkoxybenzoyloxy)benzylideneamino diphenyl ether, its 3,4′-analogue, and 1,4-bis[4-[4-(4-alkoxybenzoyloxy)benzylideneamino phenoxy benzene have been found to exhibit mostly an enantiotropic nematic phase. The clearing points of these three homologous series are rather close to each other; for example, the methoxy members give 340,325, and 333°C respectively and the decyloxy members 222,213, and 231°C, suggesting no substantial difference in the molecular shape though the molecules are not quite linear. On the other hand, the mesophase appearing in 4,4′-bis[4-(4-alkoxybenzoyloxy)benzylideneamino diphenylmethanes is of the smectic C type. Thus, the importance of the nature of one-unit linking groups as a factor determining the type of mesophase was demonstrated.

Key Words:

• Nematic
• smectic
• ether linkage
• methylene linkage
• non-linear configuration