Hydrogen bonded liquid crystalline heterodimers incorporating alkoxystilbazoles and alkoxy-4-pyridones

Abstract

The preparation and characterisation of a series of hydrogen bonded liquid crystalline dimers containing benzoic acid, alkanoic acid and phenol donors and alkoxy-stilbazole or alkoxy-4-pyridone hydrogen bond acceptors are reported. These heterodimers possess strong intermolecular donor-acceptor hydrogen bonding. The heterodimers, as well some of the individual components used in their preparation, possess liquid crystalline phases.

Mesophase behaviour of azobenzene-based angular supramolecular hydrogen-bonded liquid crystals

“…[5][6][7] Many SMHBLC materials could be easily obtained by solvent dissolving or heating or mechanical grinding the H-bond precursors without time-consuming or expensive chemical synthesis. [8][9][10] Most of the H-bonded mesogens studied are based on the rod-like intermolecular H-bonding [1][2][3][4][5][11][12][13][14] and there is an increasing interest towards the formation of bent-core SMHBLCs through intermolecular hydrogen-bond formation. [15][16][17][18][19][20][21][22][23][24][25] Azo-based LCs have attracted considerable attention because of their potential application in optical storage, [26] and recently the azo linkage was found to be a very useful building …”

Effect of bent-shape and calamitic-shape of hydrogen-bonded mesogens on the liquid crystalline properties

“…Fortunately, H-bond self-assembly has been proven to be one of the most facile approaches to prepare materials or even devices. [18][19][20] With the facileness of selfassembly preparation and the convenience to adjust the composition of the H-bond precursors, many functional materials and devices could be easily obtained by solventdissolving or heating or mechanical grinding the H-bond precursors without conventional time-consuming and expensive chemical synthesis [21][22][23]; for example, incorporation of H-bonding group such as stilbazole units with alkoxy benzoic acid or phenol to construct polymers, [24,25] near-infrared polymer dispersed liquid crystal film [26] and broadband reflection films. [27] It was also effective to introduction of H-bonding group to stabilise columnar phases, [28] twist-bend nematic phase, [29] BP [22] and twist-grain boundary phase.…”

Synthesis and mesophase behaviour of branched azobenzene-based supramolecular hydrogen-bonded liquid crystals

“…1 H NMR and 13 C NMR spectra on Bruker AV400 instrument in DMSO and CDCl 3 . The mesogenic properties were studied through an Olympus BX-51 Polarizing Optical Microscope (POM) equipped with a Linkam Scientific LTS 350 heating/freezing stage.…”

“…With the facileness of self-assembly preparation and the convenience to adjust composition of the H-bond precursors, many functional materials and devices could be easily obtained by through solvent dissolving or heating or mechanical grinding the H-bond precursors without conventionally time-consuming and expensive chemical synthesis [1][2][3]. The simplest examples of H-bonded LCs are p-alkoxy benzoic acid homodimers in which the rigid mesogenic cores are formed by head-to-head hydrogen intermolecular bonding [4].…”

“…In H-bonded LC heterodimers, the rigid mesogenic core is formed by the H-bond between a donor and an acceptor. For example, the intermolecular N-HO H-bonded mesogen could be built from 4-alkoxybenzoic acid vs. isonicotinate or nicotinate derivative [5,6], 4-alkoxybenzoic acid vs. 4-alkylpyridine [1,7] or 4-alkoxylpyridine [8], 4-alkoxybenzoic acid vs. bipyridyl compound [9,10], 4-alkoxybenzoic acid vs. heptyl p-hydroxy benzoate [11], 4-alkoxyphenol vs. 4-alkylpyridine [12,13] and multiple H-bonding [14,15]. The intermolecular H-bonds were thus widely used for the inducting LC both in the low-molecular-weight system [16] and in the side chain of polysiloxanes [17].…”