Araujo Dias Antônio Junio, Muranaka Atsuya, Uchiyama Masanobu, Tanaka Ken, Nagashima Yuki
Department of Chemical Science and Engineering, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo, 152-8550, Japan.
Molecular Structure Characterization Unit, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
Commun Chem. 2024 Jun 4;7(1):126. doi: 10.1038/s42004-024-01208-0.
Photolysis is an attractive method in organic synthesis to produce free radicals through direct bond cleavage. However, in this method, specific irradiation wavelengths of light have been considered indispensable for excitation through S-S or S-T transitions. Here we report the photoinduced homolysis of electronegative interelement bonds using light at wavelengths much longer than theoretically and spectroscopically predicted for the S-S or S-T transitions. This long-wavelength photolysis proceeds in N-Cl, N-F, and O-Cl bonds at room temperature under blue, green, and red LED irradiation, initiating diverse radical reactions. Through experimental, spectroscopic, and computational studies, we propose that this "hidden" absorption is accessible via electronic excitations from naturally occurring vibrationally excited ground states to unbonded excited states and is due to the electron-pair repulsion between electronegative atoms.
光解是有机合成中一种通过直接键断裂产生自由基的有吸引力的方法。然而，在这种方法中，特定的光照射波长被认为是通过S-S或S-T跃迁进行激发所必不可少的。在此，我们报道了使用比理论和光谱预测的S-S或S-T跃迁波长长得多的光，实现电负性元素间键的光致均裂。这种长波长光解在室温下于蓝色、绿色和红色发光二极管照射下，在N-Cl、N-F和O-Cl键中进行，引发各种自由基反应。通过实验、光谱和计算研究，我们提出这种“隐藏”吸收可通过从自然存在的振动激发基态到未键合激发态的电子激发来实现，并且是由于电负性原子之间的电子对排斥作用。
