Facile B–N Covalent Bond Fusion in <i>N</i> , <i>N′</i> ‐Diaryldihydrophenazines: Achieving Efficient Narrowband Electroluminescence and Controlled Redox Activity
Abstract
ABSTRACT Covalently fusing multiple B–N units into redox‐active polycyclic aromatic hydrocarbons (PAHs) offers a powerful strategy for creating π‐extended systems with novel functionalities, but it remains a formidable challenge. Here, we report a facile, one‐pot, and lithium‐free NH‐directed borylation to construct a series of 5,10‐dihydro‐5,10‐diphenylphenazine (DPPA) derivatives fused by two or four B–N covalent bonds. Such a multiple B–N locking is found not only to enforce molecular rigidity and suppress excited‐state structural relaxation, but also to profoundly modulate the electronic structure and antiaromaticity of the central DPPA core. Interestingly, the resultant quadruply fused system (4BN‐Ph) can function as an unprecedented narrowband orange‐red thermally activated delayed fluorescence (TADF) emitter, enabling efficient electroluminescence with a record‐high external quantum efficiency of 31.2% and a notably small full‐width at half‐maximum of 32 nm at an emissive peak of 595 nm. Also, 4BN‐Ph displays intriguing redox‐controlled properties, since a stepwise oxidation generates near‐infrared‐absorbing open‐shell radical cations and closed‐shell dications. This work establishes a modular route to PAHs incorporating multiple B–N covalent bonds, with exceptional optoelectronic and spintronic properties.
Article Details
Authors (15)
Danrui Wan
Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education; School of Chemical Science and Technology, Yunnan University National Center for International Joint Research of Photoelectronic Energy Materials and Application Kunming P. R. China
Chenglong Li
Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610, United States
Guoyun Meng
Xiangqin Gan
Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education; School of Chemical Science and Technology, Yunnan University National Center for International Joint Research of Photoelectronic Energy Materials and Application Kunming P. R. China
Jianping Zhou
Qi Wang
Yafei Shi
College of Life Sciences, Xinyang Normal University
Shuai Xiao
Yuanchun Yue
Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education; School of Chemical Science and Technology, Yunnan University National Center for International Joint Research of Photoelectronic Energy Materials and Application Kunming P. R. China
Shaobiao Zhu
Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education; School of Chemical Science and Technology, Yunnan University National Center for International Joint Research of Photoelectronic Energy Materials and Application Kunming P. R. China
Liang Shan
Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine in St.
Dongdong Zhang
Pangkuan Chen
Beijing Key Laboratory of Photoelectronic/ Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering Beijing Institute of Technology Beijing P. R. China
Lian Duan
Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry
Junqiao Ding
Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education; School of Chemical Science and Technology, Yunnan University National Center for International Joint Research of Photoelectronic Energy Materials and Application Kunming P. R. China