Single-Site Nickel-Anchored Photosensitive Covalent Organic Framework for Metallaphotocatalytic C─S/C─N...

The development of multifunctionally heterogeneous catalysts, simultaneously bearing photosensitizer and nonnoble metal catalyst in close spatial proximity, represents a promising solution for promoting metallaphotoredox-mediated catalysis, albeit it remains challenging. Herein, a single-site Ni-functionalized photosensitive covalent organic framework (COF), TTA-BPyDA(Ni)-COF, has been constructed by implementing a postsynthetic metallization strategy in a triazine-based COF scaffold. The precise integration of photosensitizer and Ni-catalytic active centers within TTA-BPyDA(Ni)-COF not only dramatically improves the metallaphotocatalytic (MPC) performance in C─S/C─N cross-coupling reaction between diverse thiols/amines and aryl iodides with electron-rich/neutral/deficient groups but also confers TTA-BPyDA(Ni)-COF with outstanding recyclability and durability compared with its homogeneous counterpart. Importantly, the MPC C─S/C─N reaction mechanisms have been well established by comprehensive experimental and theoretical simulations. This work offers valuable insights for developing single-site nonnoble metal-functionalized COF catalytic platforms that integrate photoredox centers with catalytic transition-metal cores.