ABSTRACT

A novel α-cyanostilbene-containing tetraphenylethylene-based discotic LC with 3,4,5-tridecyloxy benzene units at the terminal was synthesized by Ti-catalyzed McMurry coupling, Pd-catalyzed Suzuki coupling and Knoevenagel reactions as key steps. The liquid crystal and photophysical properties were well demonstrated by polarizing optical microscopy (POM), differential scanning calorimetry (DSC), X-ray scattering (XRD), molecular dynamics (MD) and optical experiments. The compound could self-assemble into Col_hex/p6mm mesophase in a wide temperature range. It is interesting that two discotic molecules formed one columnar slice, which was attributed to the twisted conformation of propeller-like TPE and α-cyanostilbene. The photophysical properties of the TPE-based DLCs including solvatochromism and aggregation-induced emission (AIE) behaviors were systematically investigated demonstrating large Stokes shifts, high fluorescence quantum yields and strong fluorescence in both solution and aggregated states. This work indicated that the combination of different AIE-active units into one LC molecule could induce complex self-assembly structure and excellent fluorescence properties.

摘要

通过Ti催化的McMurry偶联、Pd催化的Suzuki偶联和Knoevenagel反应作为关键步骤，合成了一种新型的含α-氰基二苯乙烯的四苯基乙烯基盘状LC，其末端具有3,4,5-十三烷氧基苯单元。通过偏光显微镜（POM）、差示扫描量热法（DSC）、X射线散射（XRD）、分子动力学（MD）和光学实验很好地证明了液晶和光物理性质。该化合物可以自组装成 Col _hex/p6mm 中间相在很宽的温度范围内。有趣的是，两个盘状分子形成一个柱状切片，这归因于螺旋桨状 TPE 和 α-氰基芪的扭曲构象。系统地研究了基于 TPE 的 DLC 的光物理性质，包括溶剂致变色和聚集诱导发射 (AIE) 行为，证明了大斯托克斯位移、高荧光量子产率和在溶液和聚集状态下的强荧光。这项工作表明，将不同的 AIE 活性单元组合成一个 LC 分子可以诱导复杂的自组装结构和优异的荧光性能。