A novel liquid crystal core unit 5,6-dihydro-4H-cyclopenta[b]thiophene was designed and synthesized in four steps and three mesogens containing terminal cyano group were then obtained. The effects of this skeleton on the mesophase and physical properties of liquid crystals were then investigated by compared with two series of reference compounds based on 1,4-disubstituted phenylene and disubstituted phenylcyclohexane and found this unit can benefit the formation of the nematic phase. Besides, both the birefringence (Δn) and dielectric anisotropy (Δε) values were increased after the introduction of this core unit. Density function theory calculations suggested that the combination of thiophene and cyclopentane had increased the height/width ratio and linearity of the mesogens which can stabilise the liquid crystal phase. Five different liquid crystals based on this new core were synthesized at last to further illustrate the usefulness of this core in constructing high birefringence and large dielectric anisotropy liquid crystals with wide nematic phase interval.

设计并合成了一种新型的液晶核心单元5,6-二氢-4 H-环戊[ b ]噻吩，分四个步骤合成了三个含氰基末端的介晶。然后，通过与基于1,4-二取代的亚苯基和二取代的苯基环己烷的两套参考化合物进行比较，研究了该骨架对液晶的中间相和物理性能的影响，发现该单元有利于向列相的形成。此外，双折射（Δn）和介电各向异性（Δε）值在引入此核心单元后有所增加。密度泛函理论计算表明，噻吩和环戊烷的结合提高了液晶元的高度/宽度比和液晶元的线性，可以稳定液晶相。最后合成了五种基于该新核的不同液晶，以进一步说明该核在构建具有宽向列相间隔的高双折射和大介电各向异性液晶中的实用性。