Abstract

New series of chalcone derivatives were built up from fluorobenzaldehyde and 4-hydroxyacetophenone as a starting material then further reacted with terminal alkylester chains to obtain the target compounds. The effect of the terminal chain on mesogenic and photochemical properties was discussed in detail. These series consist of four compounds that differ by the length of the alkyl chain.The branched-arm and chiral core quantity affected the liquid crystalline properties. The synthesized compounds were investigated for their liquid crystal properties and mesophase characteristics by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). The compounds (5–7) display nematic phase in the heating cycle while there is no liquid crystal behavior of compound (4). Studying the structure–property relationship and the presence of the halogen atom, it was proposed that, the less carbons number in the alkyle chain will increase the phase transition temperature to generate the nematic phase. The molecular structure of the synthesized compounds was confirmed by spectroscopic analysis.

摘要

以氟苯甲醛和4-羟基苯乙酮为起始原料构建了一系列新的查尔酮衍生物，然后进一步与末端烷基酯链反应以获得目标化合物。详细讨论了末端链对介晶和光化学性质的影响。这些系列由四种烷基链长度不同的化合物组成。支链和手性核的数量影响液晶性能。通过差示扫描量热法（DSC）和偏振光学显微镜（POM）研究了合成的化合物的液晶性质和中间相特性。化合物（5-7）在加热周期中显示向列相，而化合物没有液晶行为（4））。研究了结构-性质的关系以及卤素原子的存在，有人提出，烷基链中碳原子数越少，相转变温度就会升高，从而产生向列相。通过光谱分析确认了合成化合物的分子结构。