Chiral tetraphenylethenes as novel dopants for calamitic and discotic liquid crystals

摘要

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 mu m(-1) for 13/1, 12.8-16.5 mu m(-1) for 13/2, 8.0-28.7 mu m(-1) for 13/3 and 2.1-2.9 mu m(-1) 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.