Shi, Qian-QianPei, ZhipengSong, JinshuaiLi, Shi-JunWei, DonghuiCoote, MichelleLan, Yu2023-10-162023-10-160002-7863http://hdl.handle.net/1885/303319Diradical generation followed by radical-radical cross-coupling is a powerful synthetic tool, but its detailed mechanism has yet to be established. Herein, we proposed and confirmed a new model named relayed proton-coupled electron transfer (relayed-PCET) for diradical generation, which could open a door for new radical-radical cross-coupling reactions. Quantum mechanics calculations were performed on a selected carbene-mediated diradical cross-coupling reaction model and a designed model, and the exact electronic structural changes during the radical processes have been observed for the first time.The authors gratefully thank the financial support from National Natural Science Foundation of China (Nos.21773214, 21822303, and 21772020), Natural Science Foundation for Excellent Young Scientist in Henan Province (No. 212300410083), 111 Project (D20003), Backbone Teacher Project (2020GGJS016), and the National Super-computing Center in Zhengzhou. M.L.C. gratefully acknowledges an Australian Research Council Laureate Fellowship (FL170100041). Z.P. acknowledges helpful discussions with Prof. Gino DiLabio on PCET mechanisms.application/pdfen-AU© 2022 American Chemical Society2022-02-2310.1021/jacs.1c12360