Based on 5-(4-hydroxyphenyl)-2-octylpyrimidine 8, 5-phenylpyrimidine derivatives 3–7, 9 with different spacer chain lengths (C2 up to C6) and different terminal polar groups (Br, Cl, N3, OH, CN) were synthesized by etherification and nucleophilic substitution. The mesomorphic behaviour of these compounds was investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction (WAXS and SAXS) and revealed smectic A mesophases for bromides, chlorides and azides 3, 4 and 6. For these compounds a maximum phase width was observed for the C5 spacer regardless of the terminal group, whereas the hydroxy- and cyano-substituted derivatives 5 and 7, respectively, were non mesomorphic and showed only melting transitions.
根据5-(4-羟基苯基)-2-辛基嘧啶8,合成了具有不同间隔链长度(C2至C6)和不同末端极性基团(Br、Cl、N3、OH、CN)的5-苯基嘧啶衍生物3-7、9,通过醚化和亲核取代反应。通过差示扫描量热法(DSC)、偏光光学显微镜(POM)和X射线衍射(WAXS和SAXS)研究了这些化合物的向列型液晶行为,发现溴化物、氯化物和叠氮化物3、4和6具有A相向列型液晶。对于这些化合物,无论末端基团如何,C5间隔链的最大相宽度均为观察到,而羟基和氰基取代衍生物5和7则为非向列型液晶,并仅显示熔化转变。