Yang Yuzhen, Zeng Qin, Zhou Weiqiao, Jiang Junjie, Zhang Zihao, Guo Song, Liu Yuanli
Guangxi Key Laboratory of Optical and Electronic Materials and Devices, College of Materials Science and Engineering, Guilin University of Technology, Guilin 541004, China.
Materials (Basel). 2023 Jun 29;16(13):4702. doi: 10.3390/ma16134702.
Two novel ionic red/near-infrared Ir(III) complexes (Ir1 and Ir2) were reasonably designed and prepared using 2-(1-isoquinolinyl)-9,10-anthraquinone as the main ligand and 4,4'-dimethyl-2,2'-bipyridyl and 4,4'-dimethoxy-2,2'-bipyridyl as the auxiliary ligands, respectively. Both complexes showed bright phosphorescence in solution (peak at 618 nm with a shoulder at 670 nm). Interestingly, the phosphorescence peak of two Ir(III) complexes showed a blue-shift of about 36 nm after being ground. Simultaneously, both complexes exhibited mechanical force-induced enhanced emission, and the intensity of the luminescence for Ir1 and Ir2 increased by around two times compared to the one before being ground, respectively. Powder X-ray diffraction (PXRD) and time-dependent density functional theory (TD-DFT) calculation were utilized to understand well the mechanism of this phenomenon and suggested that the destruction of the well-ordered crystalline nature and the decline in triplet-triplet annihilation maybe responsible for the pressure-induced blue-shift and the enhancement of the phosphorescence.
以2-(1-异喹啉基)-9,10-蒽醌为主要配体，分别以4,4'-二甲基-2,2'-联吡啶和4,4'-二甲氧基-2,2'-联吡啶为辅助配体，合理设计并制备了两种新型离子型红色/近红外Ir(III)配合物（Ir1和Ir2）。两种配合物在溶液中均表现出明亮的磷光（峰值在618 nm，伴有670 nm的肩峰）。有趣的是，两种Ir(III)配合物的磷光峰在研磨后出现了约36 nm的蓝移。同时，两种配合物均表现出机械力诱导的发光增强，Ir1和Ir2的发光强度分别比研磨前增加了约两倍。利用粉末X射线衍射（PXRD）和含时密度泛函理论（TD-DFT）计算来深入理解这一现象的机制，结果表明，有序晶体结构的破坏和三重态-三重态湮灭的减少可能是压力诱导蓝移和磷光增强的原因。
