Institute of Molecular Aggregation Science, Tianjin University, 300072, Tianjin, China.
Department of Chemistry, Wuhan University, 430072, Wuhan, China.
Angew Chem Int Ed Engl. 2023 Jun 12;62(24):e202218994. doi: 10.1002/anie.202218994. Epub 2023 May 4.
No matter photoinduced organic radicals have been reported frequently, they are usually non-luminescent at ambient conditions. The internal mechanism on stability and electronic transitions of photoinduced radicals, is thus crucial for the development of relevant materials. Herein, a series of photoinduced radical emission systems were developed conveniently through doping benzoic acids into the hydrogen donor polyvinyl alcohol (PVA) matrix. Visual photoinduced radical emission and photochromism could be observed on Ph-3COOH@PVA film with the formation of cyclohexadienyl-type structure. For the first time, radical afterglow appeared with energy transfer from triplet state. The appropriate introduction of carboxylic groups to three nonadjacent carbon atoms on the benzene ring was the best for decreasing spin population and promoting electronic transitions of the radical. This study largely expands the radical emission property from both internal mechanism and practical application.
尽管光致有机自由基已被频繁报道，但它们在环境条件下通常是非发光的。因此，光致自由基的稳定性和电子跃迁的内在机制对于相关材料的发展至关重要。在此，通过将苯甲酸掺杂到供氢聚合物聚乙烯醇（PVA）基质中，方便地开发了一系列光致自由基发射体系。Ph-3COOH@PVA 薄膜在形成环己二烯型结构时，可观察到可视光致自由基发射和光致变色。首次出现了来自三重态的能量转移的自由基余晖。将羧酸基团适当引入苯环上三个非相邻的碳原子上，对于降低自由基的自旋密度和促进电子跃迁最为有利。这项研究从内在机制和实际应用两个方面极大地扩展了自由基发射性能。
