Laterally Brominated Symmetric Liquid Crystal Trimers with (S)-(-)-2-Methylbutyl-4′-(4″-phenyl)benzoate Exhibiting N* and Blue Phases

Abstract

The series of eight symmetric trimers, 4,4 0 -bis{x-[2-methylbutyl-4 0 -(4 00 -phenyl) benzoateoxy]-3-bromo-4-alkyloxybenzylidene}-1,4-phenylenediamines has been synthesized and characterized. Except pentyl and undecyl homologues, the seven-ring chiral trimers exhibit the enantiotropic N Ã phase. In addition to the N Ã phase, the odd trimers with heptyl and nonyl spacers also exhibit the blue phase with platelet texture. The nematogenic properties of the trimers are attributed to the presence of two lateral bulky bromine atoms in the central mesogenic core. The suppression of mesophase thermal stability is largely due to the increase in molecular breadth at positions the bromine atoms are attached, which results in weaker overall lateral intermolecular attraction. The thermal properties of the trimers are also compared to those of the earlier reported analogous trimers that do not possess any lateral substituents in the mesogenic cores.

The synthesis and enhanced thermal-optical properties of nanocomposites fabricated from gold nanoclusters ([Au25(SC12H25)18]TOA) and non-linear S-shaped liquid crystalline materials

“…The odd–even effect is a common observation especially when a series of compounds consists of a hydrocarbon chain with odd and even numbers of carbons. 38,47–49…”

Novel oxazepinedione-derived symmetric dimers: synthesis and mesophase characterisation of seven-membered heterocyclic compounds

“…The intermediates of dimers 2a-e resulted from the Williamson's etherification between compound 1 and various α,ω-dibromoalkanes ranging from C 6 H 12 Br 2 to C 12 H 24 Br 2. [26][27][28] The title compounds 2a-e was subsequently reacted with cyclic anhydrides to yield desired compounds 3a-e, 4a-e and 5a-e.…”

Synthesis and phase transition studies of new dimer compounds connected to a 1,3-dimethylbarbituric acid core

“…Compound 1 was synthesized via a condensation reaction between 4-hydroxybenzaldehyde with 1,6-dibromohexane, 1,8dibromohexane, and 1,10-dibromohexane. 14 Compounds 2a-f resulted from the reaction between hydroxybiphenyl-4-carboxyliacid and various alcohols ranging from C 6 H 14 O to C 16 H 34 O. Compounds 3a-r were prepared from the Williamson ether synthetic reactions between compounds 1a-c and compounds 2a-f.…”