Li Bian, Zhang Junde, Wang Juan, Chen Xiaofang
Suzhou Key Laboratory of Macromolecular Design and Precision Synthesis, Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China.
Molecules. 2024 Dec 9;29(23):5811. doi: 10.3390/molecules29235811.
Cyanostilbene (CS)-related conjugated groups can be considered as dual functional groups of AIEgen and mesogen to construct photoluminescent liquid crystals, and it is essential to study the relationship between their molecular structures and compound properties systematically. In this paper, we designed and synthesized linear and bent-shaped CS derivatives containing ester- and amide-connecting groups and different substituted numbers of alkoxy tails. Their phase behaviors and photophysical properties were investigated in depth. The bent-shaped compounds with the mono-substituted alkoxy tail exhibit a smectic C structure, and those containing two or three alkoxy tails possess a hexagonal columnar phase structure. The compounds exhibit aggregation-induced emission (AIE) properties in tetrahydrofuran (THF)/water mixtures. When the water fraction increases to a certain threshold, a dramatic increase in emission intensity and a red-shift in the fluorescence emission peak are detected. The emission peaks of the ester-type compounds in solid states are around 480 nm, and those of the amide-type compounds are extended to 590 nm, exhibiting versatile luminescent colors. Moreover, thermochromic and photochromic fluorescence-responsive properties are witnessed in these CS derivatives. This work provides a new strategy for the design and synthesis of fluorescent liquid crystalline materials with multiple response properties.
氰基二苯乙烯（CS）相关的共轭基团可被视为聚集诱导发光体（AIEgen）和介晶基元的双功能基团，用于构建光致发光液晶，系统研究它们的分子结构与化合物性质之间的关系至关重要。本文设计并合成了含有酯基和酰胺基连接基团以及不同烷氧基尾取代数的线性和弯曲形CS衍生物。深入研究了它们的相行为和光物理性质。具有单取代烷氧基尾的弯曲形化合物呈现近晶C结构，而含有两个或三个烷氧基尾的化合物具有六方柱状相结构。这些化合物在四氢呋喃（THF）/水混合物中表现出聚集诱导发光（AIE）性质。当水含量增加到一定阈值时，检测到发射强度急剧增加且荧光发射峰发生红移。酯型化合物在固态下的发射峰约为480 nm，酰胺型化合物的发射峰扩展至590 nm，呈现出多样的发光颜色。此外，在这些CS衍生物中还观察到热致变色和光致变色荧光响应性质。这项工作为设计和合成具有多重响应性质的荧光液晶材料提供了一种新策略。
