含氟链不对称苯并菲盘状液晶的合成及疏氟效应对介晶性的影响  

Synthesis of unsymmetric triphenylene discotic liquid crystals with semi-fluorinated chain and the influence of fluorophobic effect on mesogenic behaviors

作　　者：杨高帆[1] 赵可清[1] 余文浩[1] 胡平[1] 汪必琴[1] 

机构地区：[1]四川师范大学化学与材料科学学院,成都61006

出　　处：《中国科学（B辑）》2009年第6期507-517,共11页Science in China(Series B)

基　　金：国家自然科学基金项目(批准号:50473062;50673069;50811140156)资助

摘　　要：盘状液晶分子中引入氟代烃链并利用疏氟效应(fluorophobic effect)能有效稳定分子的柱状堆积;低对称性的盘状分子有较低的熔点和宽的介晶相温度范围.基于此,本文设计并合成了一系列半氟酯链的不对称苯并菲化合物C18H6(OCnH2n+1)4(OCH3)(O2CC2H4C6F13)(1),及相对应的不含氟化合物C18H6(OCnH2n+1)4(OCH3)(O2CC8H17)(2),n=4～8.化合物结构通过核磁和质谱表征.介晶性通过差示扫描量热法和偏光显微镜进行了研究.结果显示:化合物均为柱状互变热致液晶.含氟链化合物1a～1e与相对应的化合物2a～2e比较,有更高的熔点和清亮点.合成的多数化合物为室温液晶.The fluorophobic effect of semi-fluorinated chain of discotic molecule efficiently improves the stability of columnar mesophase. Low symmetric discogens exhibit decreased melting points and wide mesophase ranges. A series of triphenylene derivatives 1, C18H6（OCnH2n＋1）4（OMe）（O2CC2H4C6F13）, and their hydrocarbon analogues 2, C18H6（OCnH2n＋1）4（OMe）（O2CC8H17）, n = 4-8, were synthesized for the investigation of the influence of semi-fluorinated peripheral chain and molecular symmetry on mesomorphism. The structures were characterized with ^1H NMR and Mass. The mesomorphism was studied with differential scanning calorimetry （DSC） and polarizing optical microscopy （POM）. The results showed that all triphenylene derivatives exhibited enantiotropic columnar mesophase. The semi-fluorinated triphenylenes 1a-1e displayed higher melting points and more clear points than their hydrocarbon analogies 2a-2e. Most of them were in columnar mesophase at room temperature.

关 键 词：盘状液晶 苯并菲 半氟酯链 柱状相 疏氟效应 分子对称性 

分 类 号：O753.2[理学—晶体学] TS195.6[轻工技术与工程—纺织化学与染整工程]