基于手性聚集诱导发光分子的合成、光学性质及纳米结构构筑

Fabrication of functional architectures from bottom-up molecular assembly is an important approach for the design of micro/nano devices. By deliberate designing the cooperative molecular building blocks, a controlled self-assembly can be realized to construct desirable architectures with novel functions. π-Conjugated luminescent molecules are ideal building blocks for the molecular assembly due to their unique optoelectronic properties and potential applications in optoelectronics devices and biological sensors. AIE molecules, as represented by tetraphenylethylene (TPE), silole and their derivatives, are non-emissive in solutions, but become highly luminescent in the condensed state. This unique AIE property overcomes the notorious aggregation-caused quenching (ACQ) effect that conventional fluorescent molecules normally suffered in their aggregated or solid state. Precisely self-assembling of AIE molecules into desired architectures, such as nanoparticles, nanorods and nanofibers, is still a challenging task. Among the various morphological structures, one-dimensional (1D) fluorescent nanorods and nanofibers with AIE properties are of considerable interest because they are highly demanded in optoelectronic devices for transferring current and optical signals. .In this proposal, we are planning to carry out our research on the construction of novel nano architectures with chiral AIE derivatives. By bringing chiral attachments to typical AIE scaffolds such as silole and TPE, the product molecules are expected to have optical activity, fluorescence, circular polar luminescence. By carefully designing the chiral attachments the molecules are also endowed with the ability to self-assemble into novel functional micro/nanomaterials with well-defined structures..Several factors are critical for the optical activity and self-assembling behaviours of the molecules, such as the position of the chiral center, the types of the chiral attachments, the bulky effect and the number of the chiral attachments. The influence of these factors and the underlying mechanisms that govern the assembly and optical activity will be systematically studied. NMR spectrum is employed to confirm the chemical structure of the molecules. UV, circular dichroism and CPL spectra are used to characterized the optical properties of the molecules. TEM, SEM, AFM and fluorescence microscope are used to study the self-assemblies constructed by the molecules. For the characterization of the optical activity the preparation of evenly coated film is critical. The film will be prepared in two ways, that is by spin coating and by microfluid methods on quartz surface according to what we have done in our previous research. .We also plan to construct novel micro/nano architectures simply with a template induced assembly of simple AIE molecules. The influence of the surfactant types and concentration will be studied.

分子纳米材料是构筑分子纳米器件的重要基础。设计结构新颖的构筑单元，通过分子间的非共价键作用实现分子组装结构的构筑和调控是其中的重要环节。具有共轭结构的发光分子是构筑分子纳米结构的理想单元，聚集荧光增强分子有效克服了聚集荧光淬灭问题对发光材料应用的瓶颈制约。本课题选择以噻咯分子和四苯乙烯类典型的AIE分子作为分子骨架，通过向AIE分子骨架中的苯环引入手性取代基，合成两亲性的手性AIE分子；通过改变手性取代基的类型、手性不对称中心的位置、取代基的数目等因素合成一系列手性AIE分子。通过紫外光谱、圆二色谱、荧光光谱、圆偏振发光光谱系统研究分子的光学性能；通过原子力显微镜、扫描电镜、透射电镜、荧光显微镜系统表征分子的组装结构。通过以上研究系统揭示手性取代基位置、类型、数目及空间位阻效应对分子光学性质和组装行为的影响， 为设计具有特殊光学性质的纳米结构提供理论和实验依据。

1..合成了带有胆固醇取代的四苯乙烯取代的系列化合物，分别通过酰氨基和酯基链接四苯乙烯和胆固醇；分别进行间位和对位取代。所制备的分子具有良好的力至变色性，在防伪方面具有良好的应用前景。研究结果已发表。.2..合成轴手性连二萘化合物，通过掺杂AIE 发光基元组装成二元共混体系，制备具有CPL性质的纳米结构。通过原子力显微镜表征其超分子组装结构。.3..通过液晶掺杂的方法与所合成的四苯乙烯产物共混制备二元CPL液晶体系。所制备的系列二元手性液晶共混体系具有极高的CD 和CPL特性，不对称因子达0.39。在偏光显微镜下可观测到其形成的手性向列相；通过原子力显微镜系统研究了TPE与液晶的共组装结构。