Yang Hu, Peng Su-Kao, Zheng Ji, Luo Dong, Xie Mo, Huang Yong-Liang, Cai Xuan, Wang Jizhuang, Zhou Xiao-Ping, Li Dan
College of Chemistry and Materials Science, Guangdong Provincial Key Laboratory of Functional Supramolecular Coordination Materials and Applications, Jinan University, Guangzhou, Guangdong 510632, P. R. China.
Department of Chemistry, Shantou University Medical College, Guangdong, 515041, P. R. China.
Angew Chem Int Ed Engl. 2023 Oct 16;62(42):e202310495. doi: 10.1002/anie.202310495. Epub 2023 Sep 7.
Realizing high photoluminescence quantum yield (PLQY) in the near-infrared (NIR) region is challenging and valuable for luminescent material, especially for thermally activated delay fluorescence (TADF) material. In this work, we report two achiral cyclic trinuclear Au(I) complexes, Au (4-Clpyrazolate) and Au (4-Brpyrazolate) (denoted as Cl-Au and Br-Au), obtained through the reaction of 4-chloro-1H-pyrazole and 4-bromo-1H-pyrazole with Au(I) salts, respectively. Both Cl-Au and Br-Au exhibit TADF with high PLQY (>70 %) in the NIR I (700-900 nm) (λ = 720 nm) region, exceeding other NIR-TADF emitters in the solid state. Photophysical experiments and theoretical calculations confirmed the efficient NIR-TADF properties of Cl-Au and Br-Au were attributed to the small energy gap ΔE (S = singlet, T = triplet) and the large spin-orbital coupling induced by ligand-to-metal-metal charge transfer of molecular aggregations. In addition, both complexes crystallize in the achiral Pna2 space group (mm2 point group) and are circularly polarized light (CPL) active with maxima luminescent dissymmetry factor |g | of 3.4 × 10 (Cl-Au) and 2.7 × 10 (Br-Au) for their crystalline powder samples, respectively. By using Cl-Au as the emitting ink, 3D-printed luminescent logos are fabricated, which own anti-counterfeiting functions due to its CPL behavior dependent on the crystallinity.
在近红外（NIR）区域实现高光致发光量子产率（PLQY）对于发光材料而言具有挑战性且极具价值，特别是对于热激活延迟荧光（TADF）材料。在本工作中，我们报道了两种非手性环状三核金（I）配合物，Au(4 - 氯吡唑盐) 和Au(4 - 溴吡唑盐)（分别记为Cl - Au和Br - Au），它们分别通过4 - 氯 - 1H - 吡唑和4 - 溴 - 1H - 吡唑与金（I）盐反应制得。Cl - Au和Br - Au在近红外I区（700 - 900 nm）（λ = 720 nm）均表现出具有高光致发光量子产率（>70%）的热激活延迟荧光，在固态下超过了其他近红外热激活延迟荧光发射体。光物理实验和理论计算证实，Cl - Au和Br - Au高效的近红外热激活延迟荧光性质归因于小的能隙ΔE（S = 单重态，T = 三重态）以及分子聚集体中配体 - 金属 - 金属电荷转移诱导的大自旋 - 轨道耦合。此外，两种配合物均结晶于非手性的Pna2空间群（mm2点群），并且对于它们的结晶粉末样品，分别具有圆偏振光（CPL）活性，最大发光不对称因子|g|分别为3.4×10（Cl - Au）和2.7×10（Br - Au）。通过使用Cl - Au作为发光油墨，制备了3D打印发光标识，由于其圆偏振光行为依赖于结晶度，因而具有防伪功能。
