Liquid crystalline dimeric compounds with an alkylene spacer

Abstract

Two series of compounds with dimeric molecules have been synthesized and characterized. These molecules consist of two non-mesogenic units linked by an alkylene spacer through an ester linkage. The eOE ects of varying the terminal as well as the spacer chain length on the mesomorphic properties have been studied. For compounds with an even number of carbon atoms in the spacer chains, the observed textures in the mesophases are reminiscent of those seen for the smectic phases of banana-shaped molecules.

Dimeric Salicylaldimine-Based Mesogens with Flexible Spacers: Parity-Dependent Mesomorphism

“…Thus, if the length of the terminal chains is smaller than, or comparable to, the length of the spacer, an intercalated structure is observed characterized by single-layer structures obtained by random mixing of the terminal chains and the spacer. , On the other hand, if the terminal chains are significantly longer than the spacer chain then the tails and the spacer can segregate, forming double-layer structures that can, in the case of dimers with an odd-numbered spacer, display ferroelectric or antiferroelectric properties . Although many series of symmetric dimers reported in the literature employ a Schiff base link − only a limited number of salicylaldimine-based dimers , have been studied, and in all cases the more rigid salicylaldimine moiety has been incorporated into the mesogenic unit connected to the alkylene spacer via an ester link.…”

Achiral bent-core azo compounds: effect of different types of linkage groups and their direction of linking on liquid crystalline properties

“…The compound 4-((4-n-alkyloxyphenylimino)methyl)phenol ( 8) was prepared following a procedure reported previously by us. 34 4-((4-n-Alkyloxyphenylimino)methyl)phenyl 3-(4-(4-n-dodecyloxyphenylazo) benzoyloxy)benzoate (Series D)…”

“…The analytical data obtained for one of the compounds D-10, with chain length -OC 10 H 21 are as follows: The compound 4-(4-n-alkyloxybenzylideneamino)phenol ( 9) was prepared following a procedure reported previously. 34 4-(4-n-Alkyloxybenzylideneamino)phenyl 3-(4-(4-n-dodecyloxyphenylazo) benzoyloxy)benzoate (Series E)…”

Symmetrical Dimer Liquid Crystals with Tilted Smectic Phases

“…Dimeric liquid crystals containing two rigid monomeric units connected via a flexible alkylene spacer, have been investigated intensely in the last decade [1][2][3][4][5]. One of the most important reasons why these compounds gain so much interest is because their properties are quite different from monomeric liquid crystals.…”