论文部分内容阅读
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 prop-erties 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.
Twelve triphenylene discogens with a lower periphery (abbreviated as C18H6 (OC5H11) 6-x (OR) x (x = 1,2,3), R = -C3H6CH == CH2 The thermotropic liquid crystal prop-erties 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) concluded higher clearing points than the corresponding series b (alkyne periphery), while series c (vinyloxy periphery) for 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.