Stable Ferroelectric Liquid Crystals Derived from Salicylaldimine-Core

Abstract

Five pairs of enantiomers derived from salicylaldimine-core have been prepared by condensing (R)- or (S)-4-(octan-2-yloxy)anilines with 4-formyl-3-hydroxyphenyl 4-(n-alkoxy)benzoates. They have been designed to probe the correlation between molecular structure and mesomorphism, and especially to provide stable mesogens having potential for applications in ferroelectric liquid crystal devices. Thus, they have been substituted with a chiral tail at one end and by n-alkoxy chains of varying length at the other terminal. A detailed study confirms an indistinguishable behavior of all ten mesogens exhibiting an enantiotropic chiral smectic C (SmC*) phase besides blue phase (BP) and chiral nematic (N*) phase. The SmC* phase occurring over a 50-70 °C thermal width shows ferroelectric switching with spontaneous polarization (Ps) value crossing over 100 nC/cm(2). Circular dichroism spectroscopic study of the mesophases confirms the chromophores of the molecules being in the macroscopic chiral (helical) environment.

Dielectric study of three homologous Schiff base ferroelectric liquid crystals with the variations of temperature and frequency

“…The optical textural patterns exhibited by the LC phases of these compounds, such as BP-I/II, N*, SmC* and SmX phases, were found to be precisely matching with the ones reported earlier. 37,38 The samples placed between untreated glass substrates were heated to their isotropic phase and cooled slowly. A striking platelet textural pattern of the BP-I/II phase, consisting of plates of different colors [ Fig.…”

“…The phase sequences, LC phases and their textural patterns mentioned above were found to be quite matching with the reported ones. [37][38][39]…”

Multicomponent reactions mediated by NbCl 5 for the synthesis of phthalonitrile-quinoline dyads: Methodology, scope, mechanistic insights and applications in phthalocyanine synthesis

“…Aniline 2g was prepared in two steps following reported procedures with some slight modifications [55,56].…”

Optically Biaxial, Re‐entrant and Frustrated Mesophases in Chiral, Non‐symmetric Liquid Crystal Dimers and Binary Mixtures

“…[59][60][61] The reactiono f2 ,4-dihydroxybenzaldehyde with cyanobiphenyls (1a-h) in the presenceo famild base in butanone yielded the respective O-alkylated products, namely,4 '-((w-(4-formyl-3-hydroxyphenoxy)alkyl)oxy)-4-cyanobiphenyls (2a-h). [58][59][60][61][62] Under Mitsunobu reaction conditions, [63] 4-nitrophenol was O-alkylated with the (S)-and (R)-2-octanol, to obtain (R)-4-(octan-2-yloxy)nitrobenzene (3)a nd (S)-4-(octan-2-yloxy)nitrobenzenes (5); [64][65][66][67][68] these nitro materials were catalytically hydrogenated using H 2 (1 atm, balloon) and Pd/C (10 %) in THF,t oo btain the respective (R)-4-(octan-2-yloxy)aniline (4)a nd (S)-4-(octan-2yloxy)aniline (6)i nn otable yields. [64][65][66][67][68] In the final step, anilines 4 and 6 were condensed with aldehydes 2a-h in the presence of aw eak acidi ne thanol to obtain the targeted optically active, non-symmetric dimers in excellent yields.…”