135566-38-0Relevant articles and documents
Synthesis of Isocyano and (Haloalkynyl)Biphenyls: New Thermotropic Liquid Crystals
Bailey, A. L.,Bates, Gordon S.
, p. 417 - 428 (2007/10/02)
4-n-Alkyl-4'-cyanobiphenyls (1) have achieved widespread application as stable thermotropic liquid crystals with mesophases at room temperature.The importance of the cyano group in the liquid-crystalline behaviour of these compounds is not clearly defined.By modifying this functional group with minimal changes in molecular geometry, we have found two new classes of mesomorphs, 4-n-Alkyl-4'-isocyanobiphenyls (2) and 4-n-alkyl-4'-(haloalkynyl)biphenyls (3).The synthesis of these compounds is described.Compound 2a (R = n-butyl) is non-mesomorphic, whereas compound 2b (R = n-pentyl) is a virtual liquid crystal melting at 34-5 deg C and supercooling to a nematic phase at 30 deg C, and 2c (R = n-hexyl) is a nematic liquid crystal from 9 to 19 deg C.Compounds of structure 3 (R = n-pentyl, X = Si(CH3)3, H, CH3, Cl) are not liquid crystals.The corresponding bromo- and iodoalkynes (3, R = n-pentyl, S = Br, I) are liquid crystals with mesomorphic ranges of 88-108 deg C and 110-119 deg C, respectively.
