基于噁二唑及杯芳烃结构单元的高选择性Cu2+荧光探针的合成与性质研究

By combination the unique features of 1,3,4-oxadiazole and calixarene/ thiacalixarene units, we are going to design and synthesize a novel type of highly selective fluorescent chemosensors for copper(II) ions. The chemosensors are special in that the 1,3,4-oxadiazole unit works as both a fluorophore and an ionophore, which make them have much better sensitivity and selectivity for recogonition of copper(II) ions. The mechanism for recognition of copper(II) ions will be studied systemically, and the effect of the molecular structures including calixarene/thiacalixarene skeletons with various configurations(especially the cone and 1,3-alternate conformers),the conjugation structure of the fluorophore and the different complexation model of various herocyclic oxadiazole and benzoxazole on the fluorescent and colorimetric chemosensing for copper(II) ions will be investigated in detail. The influence of the disturbing transition metal ions will also be studied carefully in this work. Then a series of bifunctional fluorescent chemosensors for copper(II) and potasium ions will be designed and their molecular logic switches triggered by K+ will be explored. On the basis of the above research results, water-soluble chemosensors with excellent properties will be developed to detect the copper(II) in polluted water and in living cells,and the effect of pH valure on the recognition of copper (II) ions will be explored. This project will not only propose some new ideas to devise highly selective fluorescent chemosensors for copper(II) ions, but also provide many organic functional compounds useful in fields of supermolecular chemistry and material chemistry, which make this research proposal to be of significance from the viewpoints of both basic science and new technology.

本项目拟设计合成基于1,3,4-噁二唑和杯芳烃/硫桥杯芳烃结构单元的高选择性Cu2+荧光探针，其特点在于1,3,4-噁二唑基团同时作为荧光发色团和离子识别基团,该结构能够提高荧光探针的灵敏性和选择性.本项目将系统研究荧光探针与Cu2+的作用机理，重点考察不同分子结构包括杯芳烃/硫桥杯芳烃,各种构象特别是锥式和1,3交替型,荧光基团的共轭长度及不同的配体结构等因素与铜离子识别性质间关系, 详细研究其它过渡金属离子对Cu2+荧光识别的影响.设计合成双功能荧光探针,探索K+对Cu2+荧光识别的逻辑开关调控作用.在此基础上,设计合成水溶性荧光探针分子,研究溶液pH值对Cu2+ 识别的影响,筛选性能优异的荧光探针用于水溶液及生物活细胞内Cu2+的检测研究.项目的实施将为高选择性Cu2+荧光探针的设计合成及应用提供新思路, 为超分子化学和材料科学提供功能材料,具有基础科学研究意义和实际应用应用价值.

依据申请书研究计划，设计合成了多个系列基于1,3,4-噁二唑及杯芳烃结构单元的新型Cu2+荧光探针化合物，详细考查了分子形状与构象对荧光识别Cu2+的影响，系统研究了分子结构与性质的关系，探索了作用机理。开发了一类H-型及盘状1,3,4-噁二唑二聚体及聚合物，该类化合物具有Cu2+识别、荧光和液晶等多种性能。本项目还拓展了研究内容，开展了柱芳烃区域选择性合成研究。项目完成了研究计划，实现了预期目标。主要结论如下：.(1) 1,3-交替构象的荧光探针 (Ia-Ic, III) 对Cu2+具有专一选择性识别能力，其灵敏性高于相应的锥式构象化合物 (IIa-IIc)；(2) 基于杯冠醚结构单元的荧光探针(IVa-IIVe, Va-Vc)可通过荧光猝灭识别Cu2+，其荧光可通过Na+增强，通过Cu2+,Na+可调控荧光性质，实现了逻辑门开关功能；(3) 基于吡啶基荧光基团的硫桥杯[4]芳烃荧光探针（VIc）可作为比率型荧光探针用于Zn2+定量检测，而基于苯并噁唑的杯芳烃化合物（VId）则为H2PO4-的比率型荧光探针，且不受其它阴离子干扰；(4) 基于杯芳烃的1,3,4-噁二唑四聚体（VIIa-VIIb）及H-型二聚体(VIIIa-VIIIe)对Cu2+具有选择识别性，但没有液晶性质。而棒状1,3,4-噁二唑单体(IXa-IXe)及盘状1,3,4-噁二唑二聚体(IX)具有液晶性质及荧光性质，但对Cu2+没有选择性识别作用；(5) 荧光滴定实验及单晶结构分析表明1,3,4-噁二唑荧光探针识别Cu2+的机理为光诱导电子转移；(6) 发展了一种选择性合成二取代及三取代柱[5]芳烃的方法，首次实现了A1B1, A1B2, A1C2,A1B1D1及A1B2D1型柱[5]芳烃的合成与分离。.项目研究结果已在Org. Lett., J. Mater. Chem. C, RSC Advance, Liq. Cryst.等期刊发表7篇学术论文，申请了3项中国发明专利，目前还有3篇研究论文及1部学术专著(1章)在出版中。项目研究成果将对高选择性高灵敏性Cu2+荧光探针及发光液晶材料的设计合成具有基础科学研究意义和实际应用价值。