Yu Xingke, Gao Fanrui, Zhao Weiyi, Lai Hongxia, Wei Lingling, Yang Cheng, Wu Wanhua
Key Laboratory of Green Chemistry & Technology of Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China.
Sichuan University-Pittsburgh Institute, Sichuan University, Chengdu 610064, China.
Dalton Trans. 2022 Jun 21;51(24):9314-9322. doi: 10.1039/d2dt01373h.
The poor excited-state properties of bis-terpyridine Ru(II) complexes have significantly limited the applications of these complexes as sensitizers in photocatalysis and triplet-triplet annihilation upconversion. In the present work, two novel ruthenium bis-terpyridine complexes (Ru-1 and Ru-2) conjugated with visible-light-harvesting bodipy chromophores were synthesized. These complexes showed strong absorption of visible light, the bodipy-localized intraligand triplet state (IL) was efficiently populated, and the phosphorescence of bodipy at room temperature in both complexes was observed. The luminescence lifetimes of these complexes were significantly prolonged, with that of the heteroleptic complex Ru-2 prolonged to 37.9 μs and that of the homoleptic bis-terpyridine complex Ru-1 unprecedentedly prolonged to 356 μs, which was hundreds of times longer than the current longest emissive state achieved in ruthenium terpyridine complexes. The ultra-long triplet lifetimes and strong visible-light absorbing ability made them new candidates of triplet sensitizers, and were first applied to TTA-UC for terpyridine Ru(II) complexes with a Ru-1/Py system showing a of 2.93% in dilute solutions at concentrations as low as 1.0 μM.
双三联吡啶钌（II）配合物较差的激发态性质严重限制了这些配合物作为光催化剂敏化剂和三重态-三重态湮灭上转换材料的应用。在本工作中，合成了两种与可见光捕获硼二吡咯发色团共轭的新型钌双三联吡啶配合物（Ru-1和Ru-2）。这些配合物对可见光有强烈吸收，硼二吡咯局部配体内三重态（IL）被有效填充，并且在两种配合物中均观察到硼二吡咯在室温下的磷光。这些配合物的发光寿命显著延长，杂配体配合物Ru-2的发光寿命延长至37.9 μs，同配体双三联吡啶配合物Ru-1的发光寿命前所未有的延长至356 μs，这比目前钌三联吡啶配合物中实现的最长发射态长数百倍。超长的三重态寿命和强烈的可见光吸收能力使它们成为三重态敏化剂的新候选物，并首次应用于三重态-三重态湮灭上转换，对于Ru-1/吡啶体系的三联吡啶钌（II）配合物，在低至1.0 μM的稀溶液中显示出2.93%的上转换效率。
