Ju Yang-Yang, Xie Liang-En, Xing Jiang-Feng, Deng Qing-Song, Chen Xuan-Wen, Huang Ling-Xi, Nie Guo-Hui, Tan Yuan-Zhi, Zhang Bin
Shenzhen Key Laboratory of Nanozymes and Translational Cancer Research, Department of Otolaryngology, Shenzhen Institute of Translational Medicine, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, Shenzhen, 518035, China.
Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China.
Angew Chem Int Ed Engl. 2025 Jan 10;64(2):e202414383. doi: 10.1002/anie.202414383. Epub 2024 Oct 25.
Multiple resonance (MR) boron-nitrogen doped polycyclic aromatic hydrocarbons (BN-PAHs) have shown compelling thermally activated delayed fluorescence (TADF), surpassing those of their hydrocarbon analogues. However, the structural variety of π-extended BN-PAHs remains narrow. In this study, we synthesized three double helical BN-doped nanographenes (BN-NGs), 2 a-2 c, and three heptagon-embedded BN-NGs, 1 a-1 c, by π-extension of the MR core. During the formation of 2 a, a nanographene with one heptagon (1 a) was obtained, whereas further dehydrocyclization of the [6]helicene units within 2 b and 2 c led to heptagon structures, yielding other two BN-NGs containing double heptagons (1 b and 1 c). These BN-NGs (2 a-2 c and 1 a-1 c) showed pronounced redshifts of 100-190 nm compared to the parent MR core, while preserving the TADF characteristics and prolonging the delayed fluorescence lifetime to the millisecond level. Furthermore, the integration of a heptagon ring into 1 a-1 c expanded the conjugation, reduced the oxidation potentials, and yielded a more flexible framework compared to those of 2 a-2 c. The enantiomers of 2 a-2 c, 1 a, and 1 c were resolved and their chiroptical properties were studied. Notably, 1 a and 1 c exhibited increased chiroptical dissymmetry factors.
多重共振（MR）硼氮掺杂多环芳烃（BN - PAHs）已表现出引人注目的热活化延迟荧光（TADF），超过了它们的碳氢化合物类似物。然而，π 扩展的 BN - PAHs 的结构种类仍然有限。在本研究中，我们通过 MR 核的 π 扩展合成了三种双螺旋 BN 掺杂纳米石墨烯（BN - NGs），即 2a - 2c，以及三种嵌入七元环的 BN - NGs，即 1a - 1c。在 2a 的形成过程中，得到了一种带有一个七元环的纳米石墨烯（1a），而 2b 和 2c 中[6]螺烯单元的进一步脱氢环化导致了七元环结构，产生了另外两种含有双七元环的 BN - NGs（1b 和 1c）。与母体 MR 核相比，这些 BN - NGs（2a - 2c 和 1a - 1c）显示出 100 - 190 nm 的明显红移，同时保留了 TADF 特性并将延迟荧光寿命延长至毫秒级。此外，与 2a - 2c 相比，在 1a - 1c 中整合七元环扩展了共轭，降低了氧化电位，并产生了更灵活的框架。对 2a - 2c、1a 和 1c 的对映体进行了拆分，并研究了它们的手性光学性质。值得注意的是，1a 和 1c 表现出增加的手性光学不对称因子。
