官能化苯并菲盘状液晶的合成及不饱柔链对介晶性的影响

合成了12个含不饱和软链的苯并菲盘状液晶化合物,C18H6（OC5H11）6-x（OR）x（x=1,2,3）,R=-C3H6CH=CH2（a）,-C3H6C≡CH（b）,-C2H4OCH=CH2（c）.化合物结构通过核磁共振氢谱和高分辨质谱表征.化合物热致液晶性通过偏光显微镜（POM）,差视扫描热量法（DSC）,和X射线衍射（XRD）进行了研究.结果显示目标化合物呈现有序的六方柱状介晶相.端炔基链化合物b系列熔点最高.乙烯氧基柔链化合物c系列有最高的清亮点和最宽的介晶性温度范围,且随着不饱和醚链数的增多,清亮点明显升高.对称苯并菲化合物sym-C18H6（OC5H11）3（OR）3比不对称化合物asym-C18H6（OC5H11）3（OR）3具有更高的熔点和清亮点.乙烯氧基柔链可极化的偶极相互作用对液晶稳定性有较大贡献.

Synthesis of functionalized triphenylene discotic liquid crystals and the influence of unsaturated periphery on mesomorphism

Twelve triphenylene discogens with unsaturated periphery（abbreviated as C18H6（OC5H11）6-x（OR）x（x = 1,2,3）,R =-C3H6CH=CH2（a）,-C3H6C≡CH（b）,-C2H4OCH=CH2（c）） were synthesized and characterized.The thermotropic liquid crystal properties were studied by using polarized optical microscopy,differential scanning calorimetry and X-ray diffractometry.The results showed that all triphenylenes exhibited hexagonal columnar mesophase.The thermotropic studies showed that series a（alkene periphery） exhibited higher clearing points than the corresponding series b（alkyne periphery）,while series c（vinyloxy periphery） exhibited highest clearing points and widest mesophase temperature ranges.We also found that the symmetric discogens sym-C18H6（OC5H11）3（OR）3 displayed higher melting points and clearing points than the asymmetric ones asym-C18H6（OC5H11）3（OR）3.