激发态构型互变配合物的组装与性能研究

In an excited state intramolecular proton transfer (ESIPT) molecule, proton donor and proton acceptor groups are in close proximity to each other. Proton transfer performing will lead to the enol*-to-keto* tautomerization, and the red shift of the emission as the loss in energy. The polar molecule can interact with the proton in the ESIPT active site, which hinders the above-mentioned ESIPT process. In the case of coordination compounds based on ESIPT ligands, because the excited states of complexes are closely related to the polarities of detected molecules, so they can detect polar molecules according to the luminescent indication. The applicant had successfully synthesized a case of coordination compound based on the ESIPT ligand in the previous work. There were both high- and low-polarity groups in the channel of the framework and this compound displayed very fast luminescent response to H2O molecules. However, there are just a handful of luminescent sensing porous coordination compounds that have been reported as constructed with ESIPT ligands, and the host-guest interaction in such sensing process has not yet been studied systematically. Herein the applicant supposes polar channels in ESIPT-based porous coordination compounds can influence not only the absorption efficiency of polar molecules, but also the interaction between the polar molecules and the ESIPT active sites, therefore they play a pivotal role in the response time, selectivity, and sensibility of the sensing process. Based on the above, the applicant plans to synthesize ESIPT molecules with pendant groups of different polarities, and then construct a series of porous coordination compounds with adjustable polar channels by reactions of the as-synthesized ESIPT ligands and metal ions. Finally, the comparative research of the relationship between the polarities of the channels and the performances of luminescence sensing will be carried out. This project will find some rules in the host-guest interaction caused by different polarity and an effective method to obtain excellent luminescent sensing materials.

激发态分子内质子转移（简称ESIPT）分子的内部存在相近的质子给体和受体，因质子转移，1）构型由醇式变为酮式；2）能量损耗使得发射峰较醇式红移。极性分子与质子作用可阻碍ESIPT过程并使原分子保持醇式。由于ESIPT基配合物的激发态构型与客体极性密切相关，因此它可根据荧光指示检测极性分子。我们前期得到一例孔道中兼含高低极性基团的ESIPT基配合物，其对水分子的荧光响应很快。但目前利用ESIPT配体构筑荧光传感多孔配合物的例子极少，该类响应过程中主客体作用的系统研究尚缺乏。我们设想，在多孔配合物中，孔道极性影响着被检物吸附效果和其与ESIPT位点的氢键作用，对荧光传感的速度、选择性、灵敏性有关键影响。基于此，申请人拟先合成含不同极性侧基的ESIPT配体，接着以此制备系列孔道极性可调的配合物，最后对孔道极性与荧光响应效果进行比较研究。本项目可得到主客体基于极性的作用规律，获得高效荧光传感材料。

项目资助期间，负责人在有机小分子和配位聚合物的合成、荧光响应性质及机理等方面开展了相关研究。取得了如下研究结果：1，总结了ESIPT有机分子及配合物在分子设计、合成、荧光响应机理、应用等方面的研究概况，并撰写了综述文章，对该类材料的研究进展、瓶颈问题、解决思路、未来展望进行了详细的阐述，对相关领域的研究工作具有一定参考指导价值；2，设计合成了系列羧酸取代的三苯基咪唑有机分子（TPI-COOH），发现其对水体现了独特的钟摆型荧光变化现象，对响应机理进行了研究，开发了水响应的荧光探针分子；3，基于铜/银碘簇和六亚甲基四胺配体合成了一系列金属簇配合物，通过调控金属-金属距离和结构的长程有序性等策略，成功制备出几例具有可调控热致发光响应材料和长余辉配合物材料；4，基于铜碘簇和1,4-二吡啶基苯、三苯基膦配体合成了一例一维结构的铜碘簇聚合物，氧气对其荧光猝灭效果良好，为潜在的氧气荧光传感材料。基于上述内容，负责人发表了相关文章5篇，授权专利2项。并培养了多名硕士研究生。