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该文用4-硝基苯甲醛和4-甲基吡啶合成了质子受体4-硝基苯乙烯基吡啶,用无水乙醇重结晶得黄色固体,其熔点126.8～128.9℃,产率27%。用4-羟基苯甲酸和1-溴代正烷合成了质子供体4-烷氧基苯甲酸,用体积分数为95%的乙醇重结晶,所得4种中间体产率都在20%左右。最后,以上述两个中间体为原料,制备了系列4-硝基苯乙烯基吡啶类氢键型液晶。IR和1H NMR证实了各中间体结构。POM、IR、DSC检测了各复合物。POM拍摄的向列相、近晶相液晶织构表明,3种该氢键复合物均呈现明显的液晶态,且n=3时为向列相,n=5、8时为近晶相;IR图谱3500～2500cm-1处峰的变化及羰基向高波数位移,证明了羧基和吡啶间的分子间氢键代替了羧基间的分子间氢键。各复合物的液晶区间范围比各相应单体增大了1倍,表明羧酸吡啶间氢键起到了稳定液晶态的作用。
In this paper, 4-nitrobenzylpyridine was synthesized from 4-nitrobenzaldehyde and 4-methylpyridine and recrystallized from absolute ethanol to give a yellow solid, mp 126.8 ~ 128.9 ℃, yield 27% . The 4-hydroxybenzoic acid and 1-bromo-n-alkane were used to synthesize proton donor 4-alkoxybenzoic acid. The recrystallization was achieved with 95% ethanol by volume. The yields of the 4 intermediates obtained were both about 20%. Finally, a series of 4-nitrostyrylpyridine hydrogen bond-type liquid crystals were prepared from the above two intermediates. IR and 1H NMR confirmed each intermediate structure. The complexes were detected by POM, IR, DSC. Nematic phase and smectic liquid crystal texture of POM showed that all three kinds of hydrogen bond complex showed obvious liquid crystal states, nematic phase when n = 3, smectic phase when n = 5 and 8, The change of the peak at 3500-2500 cm-1 and the shift of the carbonyl group to the high wave number of the IR spectrum prove that the intermolecular hydrogen bond between the carboxyl group and the pyridine replaces the intermolecular hydrogen bond between the carboxyl groups. The range of the liquid crystal range of each compound is one times larger than that of the corresponding monomers, indicating that the hydrogen bond between the pyridine carboxylic acid and the carboxylic acid serves to stabilize the liquid crystal state.