The Origin of Catalytic Benzylic C-H Oxidation over a Redox-Active Metal-Organic Framework

Selective oxidation of benzylic C-H compounds to ketones is important for the production of a wide range of fine chemicals, and is often achieved using toxic or precious metal catalysts. Herein, we report the efficient oxidation of benzylic C-H groups in a broad range of substrates under mild conditions over a robust metal-organic framework material, MFM-170, incorporating redox-active [Cu₂ ^II (O₂ CR)₄ ] paddlewheel nodes. A comprehensive investigation employing electron paramagnetic resonance (EPR) spectroscopy and synchrotron X-ray diffraction has identified the critical role of the paddlewheel moiety in activating the oxidant ^t BuOOH (tert-butyl hydroperoxide) via partial reduction to [Cu^II Cu^I (O₂ CR)₄ ] species.