Visible-Light-Enabled C-H Functionalization by a Direct Hydrogen Atom Transfer Uranyl Photocatalyst.

Abstract

The development of the uranyl cation as a powerful photocatalyst is seriously delayed in comparison with the advances in its fundamental and structural chemistry. However, its characteristic high oxidative capability in the excited state ([UO2 ]2+ * (+2.6 V vs. SHE; SHE=standard hydrogen electrode) combined with blue-light absorption (hv=380-500 nm) and a long-lived fluorescence lifetime up to microseconds have reveals that the uranyl cation approaches an ideal photocatalyst for visible-light-driven organic transformations. Described herein is the successful use of uranyl nitrate as a photocatalyst to enable C(sp3 )-H activation and C-C bond formation through hydrogen atom transfer (HAT) under blue-light irradiation. In particular, this operationally simple strategy provides an appropriate approach to the synthesis of diverse and valuable diarylmethane motifs. Mechanistic studies and DFT calculations have provided insights into the detailed mechanism of the photoinduced HAT pathway. This research suggests a general platform that could popularize promising uranyl photocatalytic performance.