Stable organic radicals are promising materials for information storage, molecular magnetism, electronic devices, and biological probes. Many organic radicals have been prepared, but most are non- or weakly emissive and degrade easily upon photoexcitation. It remains challenging to produce stable and efficient luminescent radicals because of the absence of general guidelines for their synthesis. Herein, we present a photoactivation approach to generate a stable luminescent radical from tris(4-chlorophenyl)phosphine (TCPP) with red emission in the crystal state. The mechanistic study suggests that the molecular symmetry breaking in the crystal causes changes of molecular conformation, redox properties, and molecular packing that facilitates radical generation and stabilization. This design strategy demonstrates a straightforward approach to develop stable organic luminescent radicals that will open new doors to photoinduced luminescent radical materials.

稳定的有机自由基是用于信息存储、分子磁性、电子器件和生物探针的有前途的材料。已经制备了许多有机自由基，但大多数是不发光的或弱发光的，并且在光激发下容易降解。由于缺乏合成的通用指南，生产稳定有效的发光自由基仍然具有挑战性。在此，我们提出了一种光活化方法，从三（4-氯苯基）膦（TCPP）产生稳定的发光自由基，在晶体状态下具有红色发射。机理研究表明，晶体中分子对称性的破坏会导致分子构象、氧化还原特性和分子堆积的变化，从而促进自由基的产生和稳定。