噁二唑类弯曲形液晶分子的合成

Synthesis of Bent-Core Liquid Crystals with Oxadiazole

设计并完成了3个系列弯曲形液晶分子2,5-二(4-羟基苯基)-1,3,4-噁二唑类(ODBP)衍生物的合成工作。经差示扫描量热仪(DSC)和偏光熔点测定仪测定,对称型三环醚类噁二唑系列化合物没有液晶性能;对称型五环酯类噁二唑系列化合物出现双轴向列相,相区较宽(29～54℃),但清亮点均在200℃以上;含氟原子或氰基为端基的不对称型五环酯类噁二唑系列化合物的清亮点都在270℃以上,失去双轴向列相。

Three series of bent-core liquid crystals,the derivatives of 2,5-bis-（p-hydroxyphenyl）-1,3,4-oxadiazole（ODBP）were synthesized,their transition temperatures were studied by DSC （Differential Scanning Calorimetry）and POM （Polarizing Optical Microscope）.It was found that symmetric oxadiazoline ether derivatives with three benzene rings don＇t exhibit LC phase;symmetric oxadiazoline ester derivatives with five rings（benzene or trans-cyclohexane）show biaxial nematic（Nb）phase with large temperature range（29～54℃）,but the clearing temperatures were over 200℃.Asymmetric oxadiazoline ester derivatives with F or CN as a terminal group show rather high clearing temperatures（〉270℃）,but without Nbphase.