棒-线型邻菲罗啉铂（II）配合物自组装磷光材料的构建及发光性能研究

Platinum(II) complexes possess the characteristics different from the general light emitting molecules, such as long lifetime and higher luminescent efficiency, because that they are capable to break through the spin-forbidden of triplet exciton transition. These predicts their potential applications in optoelectronic, sensing materials, probes and other fields. However, the square planar platinum(II) complexes ease to be quenched at high concentration and exhibit non-emission in aggregation because of strong intermolecular interactions, which seriously hinders their applications. Doping techniques can solve the problem of quenching, but the materials are complicated and the cost is increased. In this project, we design the rational rod-coil like platinum(II) complexes with flexible long chains and quaterphenyl group at the 5,6- and 3,8- site of molecular rod segment respectively, and possessing the auxiliary ligand with strong field effect. These rod-coil phenanthroline platinum(II) complexes are able to form phosphorescent aggregates by self-assembly. Via modulating the intermolecular interactions, these phosphorescent materials with high emissive efficiency are achieved to be constructed. These suggested that the problem of quenching of platinum(II) complexes could be solved by the facile solution processable self-assembly approach. The relationship between molecular structure of platinum(II) complexes, self-assembling conditions and intermolecular interactions, molecular packing model, supramolecular structure and phosphorescent efficiency of these self-assembled materials are then studied. The rules about the effects of molecular structure on the emissive properties of phosphorescent platinum(II) materials, and the mechanism of aggregation induced emission are revealed in this work. Furthermore, this project presents the potential applications of the self-assembled phosphorescent materials based on the phenanthroline platinum (II) complexes in biological probe for cell imaging.

铂（II）配合物可使原本禁阻的三线态发生跃迁，理论上具备优于一般发光分子的寿命长、发光效率高等特性，在光电、传感材料和探针等领域有广阔应用前景。然而，平面四边形铂（II）配合物间存在强烈的分子-分子作用，易发生高浓度淬灭，聚集态不发光或发光很弱，严重阻碍了应用。掺杂法可一定程度解决浓度淬灭问题，但使材料本身复杂化，成本增加。本项目以邻菲罗啉铂（II）配合物为研究对象，拟分别在其刚性单元5,6-位和3,8-位修饰柔性长链和四联苯基，引入强场效应辅助配体，实现棒线-型邻菲罗啉铂（II）配合物自组装诱导聚集态发光；并通过调节自组装作用力，构建高发光效率的磷光材料，为解决铂（II）配合物高浓度淬灭提供一个简便的新途径。并揭示分子结构、组装条件影响分子作用力、分子堆积方式、材料超分子结构及发光效率的内在规律；阐明自组装诱导磷光发射机理。在此基础上，进一步探讨该类材料作为生物探针在细胞成像方面的应用。

邻菲罗啉具有独特的N杂环刚性共轭平面和特殊的电子结构，是优良的N^N二齿配体，与铂配位获得平面四边形的铂配合物。在刚性邻菲罗啉（rod）配体5,6-位上链接柔性基团（coil），获得棒-线型分子，利用该结构的分子其自组装易受外界条件的调控的特点，改变自组装条件，可有效地调节分子间作用从而调控组装材料的结构和发光以及其他性能。我们合成了4个棒线型邻菲罗啉衍生物以及6个棒-线型邻菲罗啉铂配合物。解决了浓度淬灭问题，使得棒线型邻菲罗啉衍生物和配合物自组装材料发光。通过改变溶剂、温度和浓度等条件改变自组装作用力，调节自组装材料的结构和发光性能以及响应性能。揭示分子结构、组装条件等对自组装棒线型邻菲罗啉衍生物发光材料的结构和性能的影响。项目执行期间，发表了6篇SCI论文，授权了3项专利，培养了6名本科生。