Nematic Liquid Crystals with High Positive Dielectric Anisotropy

M a g e d A . O s m a n * B r o w n Boveri Research Center, Chemistry Group, CH-5405 Baden-Dättwil , Switzerland Z. Naturforsch. 34b, 1092-1095 (1979); received March 23, 1979 Liquid Crystals, Nematic Phases, High Positive Dielectric Anisotropy, Alkylamino-cyano-b iphenyls , Alkylamino-cyano-phenylbenzoates Alky laminoand formyl a lkylamino-cyano Schif f 's base, biphenyl and phenylbenzoate l iquid crystals were synthesized. The mesomorphic behaviour o f these compounds is described. The introduction of the formyl group in the higher homologues lead to the disappearance o f the mesophase. The alkylamino and formylalkylamino substituents are strong electron donating groups and lead to nematic phases with remarkably high posit ive dielectric anisotropy.