New chiral LC acrylates: Polar ordering in crystal and smectic phases

Two mesogenic acrylates derived from (R)-5-bromo-4-methylpenta-noic acid, h aving biphenyl moiety, have been synthesised and characterised by POM, DSC, X-ray, pyro- and piezoelectric techniques. The only real difference in mol ecular structure of the compounds is that the one contains terminal octylox y group (1) and the other has octanoyloxy group (2). Crystal structures of the acrylates were shown to be precursors of tilted smectic phases. Both co mpounds are monomorphic exhibiting either smectic I* phase (1) or smectic c rystal H* phase (2). 1 crystallises in non-polar space group while the crys tallisation of 2 yields crystals with a polar axis. Good correlations were found in electric responses between the crystalline phases and mesophases o f both the acrylates.