Chiral tetraphenylethenes as novel dopants for calamitic and discotic liquid crystals

Abstract

Three series of novel chiral tetraphenylethenes have been prepared: citronellyl-derived ethers 1a, b, lactate-derived ethers 2d, g, h, i and lactate-derived esters 3a-c, e-h. Helical twisting powers (HTPs) were determined for those derivatives of 1-3, which were sufficiently miscible with the nematic host 5CB 13 or the discotic nematic host hexayne 14. For binary solutions HTP values of 5.7-10.4 mm À1 for 13/1, 12.8-16.5 mm À1 for 13/2, 8.0-28.7 mm À1 for 13/3 and 2.1-2.9 mm À1 for hexayne 14/3 were determined, indicating a much stronger interaction between the C 4 -symmetrical propeller-shaped tetraphenylethenes 1-3 with the calamitc host 5CB 13 than with the discotic C 6 -symmetrical propeller-shaped host hexayne 14.(2S)-Decyloxypropionic acid (10g) According to the general procedure 0.54 g (83%) of a colourless liquid was obtained. 1 H-NMR (500 MHz, CDCl 3 ): d (ppm) ¼ 0.88 [t, 3 J ¼ 7.0 Hz, 3H, CH 2 CH 2 (CH 2 ) 7 CH 3 ], 1.18-1.38 [m, 16H, CH 2 CH 2 (CH 2 ) 7 CH 3 ], 1.45 (d,

Discotic Liquid Crystals

“…Schreivogel et al investigated chiral tetraphenylethenes 103 as dopants for calamitic and discotic liquid crystals (Scheme ). Helical twisting powers of 28.7 and 2.5 μm –1 were obtained for mixtures of 103 with calamitic nematic hosts, respectively. Varshney et al utilized octamethoxytetraphenylethene as a precursor for the oxidative cyclization toward octa-ester-substituted dibenzochrysenes 104 (Schema 44), which displayed Col h and Col r phases, in case of chiral lactate derivatives already at room temperature …”

Crosstalk‐Free Patterning of Cooperative‐Thermoresponse Images by the Synergy of the AIEgen with the Liquid Crystal

“…Our concept of patterning crosstalk‐free images is to integrate the holographic and fluorescent images with cooperative thermoresponse. A typical tetraphenylethene‐based AIEgen (TPE‐4CN) is developed for this target owing to its relatively high quantum yield of 35.2 % in bulk (Supporting Information, Figure S3), in which four 3,7‐dimethyloct‐6‐enyloxy chains are attached to ensure good solubility in the LC (up to 41 wt %). TPE‐4CN is found to exhibit a poor miscibility with the acrylate/acrylamide monomer, which would facilitate the enrichment of TPE‐4CN in the LC‐rich phase rather than the polymer‐rich phase during phase separation.…”

Pitch gradient induced by disklike chiral molecular diffusion in chiral-nematic liquid crystals

“…However, they suffer from its low processability for their poor mutual solubility with rodlike molecules even in the solvent. This can be overcome with a͒ 21 Although many applications have been suggested for disklike molecules exploring their use in energy and charge migration and optical compensation films, 22 the application of disklike molecules on wide-band reflective films has rarely been discussed in previous literatures.…”