Parida Hazretomar, Ma Fudong, Liu Zunqi, Ding Zhaoze, Ablikim Obolda
College of Chemistry and Chemical Engineering, Xinjiang Agricultural University, East Road No. 311, Urumqi 830052, China.
Molecules. 2025 Mar 17;30(6):1344. doi: 10.3390/molecules30061344.
In this study, we report two novel donor-acceptor (D-A•)-type triphenylmethyl radicals, TTM-1TPE-2Cz and TTM-2TPE-2Cz, synthesized by integrating an aggregation-induced emission (AIE)-active 2-(1, 2, 2-triphenylethenyl)-9H-carbazole (TPE-2Cz) donor with tris(2,4,6-trichlorophenyl)methyl (TTM) radical core. Despite the AIE unit's conventional ACQ-suppressing capability, both radicals exhibit complete emission quenching in solid/solution states but demonstrate 655 nm red emission in polymethyl methacrylate (PMMA)-doped films. Theoretical and experimental analyses reveal that the flexible TPE moiety unexpectedly enhances non-radiative decay while establishing a non-Aufbau electronic configuration through its strong electron-donating nature (-5.16 eV HOMO vs. -5.75 eV SOMO). Remarkably, these radicals achieve unprecedented photostability with half-lives (t₁/₂) 39,000- and 12,000-fold greater than pristine TTM, respectively. This work not only presents a synthetic strategy for stable radicals through non-Aufbau electronic engineering but also elucidates critical structure-property relationships between AIE units and radical photophysics.
在本研究中，我们报道了两种新型供体-受体（D-A•）型三苯甲基自由基，即TTM-1TPE-2Cz和TTM-2TPE-2Cz，它们是通过将具有聚集诱导发光（AIE）活性的2-(1, 2, 2-三苯乙烯基)-9H-咔唑（TPE-2Cz）供体与三（2,4,6-三氯苯基）甲基（TTM）自由基核心整合而合成的。尽管AIE单元具有传统的抑制聚集猝灭（ACQ）能力，但这两种自由基在固态/溶液状态下均表现出完全的发射猝灭，但在聚甲基丙烯酸甲酯（PMMA）掺杂薄膜中表现出655 nm的红色发射。理论和实验分析表明，柔性的TPE部分意外地增强了非辐射衰减，同时通过其强给电子性质（最高占据分子轨道（HOMO）为-5.16 eV，单占据分子轨道（SOMO）为-5.75 eV）建立了非构造原理电子构型。值得注意的是，这些自由基实现了前所未有的光稳定性，半衰期（t₁/₂）分别比原始TTM大39,000倍和12,000倍。这项工作不仅提出了一种通过非构造原理电子工程合成稳定自由基的策略，还阐明了AIE单元与自由基光物理之间的关键结构-性质关系。
