瓜环主客体荧光材料的设计、组装及性能研究

Covalent attachment of substituents to organic fluorescent dyes has been commonly done to fabricate functional luminescent materials. However, it often involves difficult and tedious organic synthesis with multiple steps and higher cost. Supramolecular assembly has recently been proven to be an efficient way of fabricating smart fluorescent materials, due to the reversibility, diversity and flexibility of non-covalent bonds. Interestingly, our recently study suggested that cucurbiturils as macrocylic host has unique advantages in constructing water-soluble multicolor organic fluorescent dyes. In this project, cucurbit[n]urils (n =6, 7, 8, 10,14) will be selected as the host receptors, and a series of cationic organic fluorescent dyes with good optical properties and water solubility will be designed and synthesized. Then, a number of host-guest based Q[n]/dye assemblies through multiple non-covalent interactions will be systematically investigated. In particular, we intend to fully evaluate the response relationship between the assembly structures of Q[n]/dye and the resulting fluorescence properties. Furthermore, to explore the Q[n]/dye assemblies in fluorescent probes, solid fluorescent materials, and fluorescence images in living cells, we hope an application model of host-guest interactions derived fluorescent dyes could be established. Overall, we expect that the design strategies and the optical properties of the proposed project should be of interest to the functional organic fluorescent materials with simple, efficient and economic fashions.

共价健修饰有机染料分子是目前制备功能发光材料的常用手段，但是该方法需要多步合成、获取成本较高。近年来，超分子自组装荧光材料，由于非共价键的可逆性、多样性及灵活性而备受关注。我们的近期研究结果显示瓜环作为大环主体分子在构筑水溶性多色荧光体系方面具有非常独特的优势。因此，本项目拟以不同空腔大小的系列瓜环为基本单元，设计、合成具有良好光学性能及水溶性的阳离子型有机染料客体分子，通过超分子非共价键作用，构筑系列瓜环/染料主客体组装体；探讨瓜环主客体组装结构与荧光性能间的响应规律；并通过瓜环/染料组装体在荧光探针、固体荧光材料及生物体系荧光识别及成像等方面的研究，建立主客体非共价键荧光染料的应用模型，为新型有机荧光功能材料的制备和应用提供一种简单、高效、经济的新途径。

近年来，超分子自组装有机发光材料，由于非共价键的可逆性、多样性及灵活性而备受关注。在生物细胞成像，光动力治疗，超分子催化，防伪材料等方面具有潜在应用价值。本项目按研究计划进行，研究了瓜环主客体荧光材料的组装特点及性能。主要研究成果及执行情况如下：（1）设计合成了系列具有良好光学性质及水溶性的阳离子吡啶类有机染料客体分子，考察了染料分子本身的聚集荧光性能。通过与系列瓜环进行主客体组装，探讨了主客体自组装方式及相应光学性质的变化规律与应用；（2）研究了不同瓜环空腔结构与具有电子给受体（D-A）结构的染料客体分子的荧光响应规律。发现了染料客体分子荧光信号的变化不仅与瓜环聚合度相关（主要体现在主客体组装调控染料客体分子的π-π堆积及分子间电荷转移），还与系列瓜环疏水空腔的静电势相关（主要体现在调控染料客体的分子内电荷转移强度）；（3）揭示了瓜环主客体组装高效发光的本质—“大环笼状限域”的作用，系统总结和阐述了瓜环主客体调控荧光（磷光）的特点和规律；（4）发展了瓜环主客体组装催化的荧光碳纳米量子点的新方法；（5）发现了瓜环稳定的自由基荧光及大环主客体促进的光致电子转移新现象，进一步拓展了瓜环在光电材料中的应用前景。同时，项目在执行完成预定研究计划目标的基础上合作发现了一类溶剂调控的席夫碱大环化合物聚合度及其在有机微/纳米粒子制备和组装方面的特点和优势，为大环超分子化学研究提供了新借鉴。相关研究成果以通讯作者发表在Chem. Rev., ACS Nano, Chem. Mater., Chem. Sci., ACS Appl. Mater. Interfaces, 等国内外重要化学与材料类SCI收录期刊。