含四配位有机硼单元的荧光/磷光寡聚物材料的设计、制备与双光子成像研究

Organoboron compounds with π-conjugated framework, including tri- and four- coordinate boranes, have attracted widespread attention owing to the unique electronic and optical properties. The intramolecular B-X coordination of four-coordinate organoboron compound, makes them with high thermal stabilities and fixes the π-conjugated framework in a planar fashion, and hence enhances the π-electron delocalization. So these organoboron compounds are promising materials in the field of organic electronics. There are a few N^C four-coordinate organoboron compound have been developed, and their synthetic repertoire is complicated, and also needs some expensive reagents. Electrophilic borylations of arylpyridines (EBA) is one effective strategy to create and functionalize extended π-conjugated materials, but the methodology has only recently been applied to the development of new optical or electronic materials. So it is necessary to develop a lot new N^C four-coordinate organoboron compounds with this method. In this project, we will develop a series of N^C four-coordinate organoboron oligomers with different D-A conjugated structures, and obtain full color even near – infrared emission materials. Then, the transition metal will be introduced to the four-coordinate organoboron oligomer and gain the fluorescence-phosphorescence materials with two emission property. The introduce of N^C four-coordinate organoboron and transition metal coordinate can strengthen the charge transfer transitions in D-A conjugated structure, and then increase the Stokes shifts of the material. Importantly, this also can enhance the absorbance in visible light that was extremely beneficial in realizing two-photon imaging. Finally, the four-coordinate organoboron oligomer will be used in two-photon imaging.

具π共轭的有机硼材料因具独特性能，在光电领域有着广泛的应用前景。这类材料包括三/四配位硼化合物，四配位硼因分子内B-X配位键的形成使其具较高稳定性并且使分子骨架趋于平面，有利于增大π电子离域程度，是极具潜力的一类光电功能材料。已发展的少数N^C螯合四配位硼发光材料合成复杂，试剂昂贵。而亲电芳基硼化（EAB）反应是获得N^C螯合四配位硼发光材料的一种有效手段，基于EAB构建光电材料的研究还较少，值得进一步去拓展。本项目中，我们预通过EAB反应构建一系列具有不同D-A结构的四配位硼寡聚物，获得全彩乃至近红外发射的材料；并进一步在寡聚物中引入过渡金属，获得具有荧光-磷光双发射材料；通过四配位硼或过渡金属的引入可以增强D-A结构的电荷转移跃迁，解决传统有机硼材料Stokes位移小的问题，增强可见光区的吸光度，这在成像中有利于实现双光子激发。最终将实现目标材料的生物功能性并研究在双光子成像中的应用。

具有π共轭的有机硼材料因具独特性能，在光电领域有着广泛的应用前景。这类材料包括三/四配位硼化合物，四配位硼因分子内B-X配位键的形成使其具较高稳定性并且使分子骨架趋于平面，有利于增大π电子离域程度，是极具潜力的一类光电功能材料。本项目的实施，获得的结果如下：首先，我们设计、合成了两种具有D-A结构的吩噻嗪-三芳基硼发光材料，这两种材料都具有较高的热稳定性，固态呈现强的发光。其中，含单三芳基硼取代的材料呈现延迟荧光性质。第二，我们通过分子设计分别将三芳基硼和三苯胺分别引入到含N^C螯合的四配位硼化合物中，并改变取代位置，合成了四种新型有机硼发光材料。其中，给电子三苯胺的引入使材料的发光呈明显的溶剂依赖性，并且固态和溶液发光量子效率都明显提高。最后，我们制备了三种具有近红外吸收的二硫烯镍配合物。这三种配合物在近红外（NIR）区域都显示出较强的吸收，NIR最大吸收波长分别位于854、942和1010 nm。将NIR-II吸收的配合物与两亲性聚合物作用形成纳米粒子，该纳米粒子具有好的水相分散性、低的生物毒性、强的光稳定性，并且在1064 nm 激光照射下，该纳米粒子在水溶液中呈现高的光热转换效率（63.6%），这是目前金属双二硫烯配合物中是最高的。通过体外对Hela细胞的毒性研究发现，该类材料在体外有较好的光热治疗（PTT）效果。