摘要:
We have prepared some new dimeric liquid crystals in which two phenylpyrimidine moieties are connected via (+/-)-trans-1,2-cyclohexanediol or p-toluenesulfon amide and investigated the transition behaviour. (+/-)-trans-1,2-Bis{6-[4-(5-octylpyrimidin-2-yl)phenoxy]hexyloxy)cyclohexane 1 was found to show enantiotropic nematic (N) and smectic A (SnA) phases with a low melting point. On the other hand, N-p-toluensulfonyl-bis{6-[4-(5-octylpyrimidin-2-yl)phenoxy}hexyloxy}amine 2 showed only a monotropic SmA phase. We discuss topological effect of the connecting group on the phase transition behaviour.