稀土-有机配位聚合物的设计合成及光学性能研究

The lanthanide coordination polymers have attracted increasing attention due to their unique optical properties, making them widely employed in white light-emitting diode (WLED), sensing, diagnosis, and bioimaging. The lanthanide coordination polymers with high quantum yield and long emitting lifetime were difficult to be obtained because it is hard to predict the triplet state energy of the ligand and to keep from the water molecules coordinating to the lanthanide ion. The conjugate atomic carboxylate ligands with or without substituent group and viologen carboxylate ligands, as well as β-diketone auxiliary, will be employed to react with singe/multi lanthanide ions through different methods, forming a series of lanthanide coordination polymers. Their crystal structures and luminescent properties will be characterized. In order to get the coordination polymers with high quantum yield and long emitting lifetime and materials with white or yellow light emitting, the triplet state energy, coordinated water molecule and concentration of lanthanide ions will be changed. Furthermore, the rules of syntheses and self-assembly, structure features, luminescent properties, as well as the relations between structures and properties of the lanthanide coordination polymers will be studied. And some of them, acting as photochromic materials and white light-emitting diodes, were also studied. This project not only expands the structures and number of the lanthanide coordination polymers, but also provides some theoretical and experimental supports for further design and synthesis of the lanthanide coordination polymers with unique structures and luminescent properties.

稀土-有机配位聚合物由于其独特的光学性能而受到人们的大量关注，并广泛应用在白光发光器件、传感、生物探针和生物成像等领域。由于配体三重态能量的难以预测以及配位水分子淬灭的影响，很难得到发光效率高、发射寿命长的稀土-有机配位聚合物材料。本项目选用共轭羧酸、取代基团修饰的共轭羧酸以及紫罗碱类羧酸为主配体，β-二酮等小分子为辅助配体，与单一／混合稀土离子组装成稀土-有机配位聚合物。通过调控配体三重态能量、配位层水分子和稀土离子的浓度，实现高效发光的稀土-有机配位聚合物晶体材料以及白光／黄光发射的稀土-有机配位聚合物晶体材料的制备。研究其合成与自组装规律、结构特点、光学性能以及结构-性能关系，探索其在光致变色、白光LED器件等方面的应用。本项研究不仅拓展了稀土-有机配位聚合物晶态材料的种类，还为设计合成具有特殊结构与光学性能的稀土-有机配位聚合物提供理论和实验支撑。

稀土-有机配位聚合物在发光材料、荧光检测材料等领域具有广泛的应用而备受国内外科研工作者的关注。稀土离子的4fn电子跃迁发光具有发射峰窄、发射寿命长、斯托克斯位移大的特点，以及有机配体对稀土离子的敏化作用，都促进了稀土-有机配位聚合物在光物理和光化学等领域的应用。发光效率和材料的稳定性是制约稀土-金属有机配位聚合物应用的主要因素。本项目拟选用共轭羧酸，与单一/混合稀土离子自组装，通过水热或溶剂热的合成方法，构筑新颖的、具有高稳定性和高发光效率的稀土-有机配位聚合物发光材料。探索稀土-有机配位聚合物的合成与自组装规律、结构与光学性能之间的关系；探讨有机配体的三重态能量、配位水分子、稀土离子的浓度等因素对稀土-有机配位聚合物光学性能的影响。并通过对以上因素的调控得到发光效率高、发射寿命长、稳定性好的稀土-有机配位聚合物发光材料。项目实施的过程中，我们通过对Eu-Tb-Dy混合稀土-配位聚合物中不同稀土离子之间的浓度以及能量转移的调控得到两例白光稀土-金属有机配位聚合物；通过碱金属对稀土配位层中水分子的竞争降低O-H键对稀土离子发光的淬灭得到高量子产率的稀土-金属有机配位聚合物；筛选出一例具有良好水稳定性且耐酸耐碱的铕-金属有机配位聚合物，实验证明该材料在水溶液中对能够灵敏和选择性的检测Fe3+ 和Cr2O72- 离子。本项目的实施将为合成具有特定结构与光学性能的稀土-有机配位聚合物提供思路与指导，也将为其在发光材料、荧光检测等领域的应用提供实验基础与信息。