SYNTHESIS OF SCHIFF BASE AND AZO LIQUID-CRYSTALLINE CROWN-ETHERS

Six Schiff's base and azo liquid crystalline crown ethers were first s ynthesized via the intermediates cis(trans)-4,4'-diaminodibenzo-18-cro wn-6 and 4'-aminobenzo-15-crown-5, respectively. The structures were e lucidated by elementary analysis, IR, H-1 NMR and MS. The mesomorphic properties were determined by DSC and optical microscopy. The relation ship between the structures of the double-armed and mono-armed crown e thers, and the mesomorphic properties were studied. We realized that w hen the L/D ratio of the double-armed crown ether was in the range of 4-8 and that of the mono-armed crowns was larger than 3, they would po ssess liquid crystallinity. This conclusion is consistent with our pre vious investigations.