Unprecedented Tetravalent Uranium Photocatalysts for Efficient C(sp ³ )─C(sp ³ ) Bond Cleavage and Formation

Abstract Photocatalysis is a pivotal area in synthetic chemistry. Despite extensive application potential in nuclear industry, uranium‐based photocatalysts are historically limited to uranyl(VI/V) redox cycle. Here, we report the discovery of the first tetravalent uranium [U(IV)] photocatalyst that enables efficient C(sp 3 )─C(sp 3 ) bond cleavage and formation under ideal visible light . The U(IV) alkoxy species mediates C─C bond cleavage in a wide range of cycloalkanols and promotes their coupling with electron‐deficient alkenes, providing access to previously unattainable molecular architectures. These U(IV) alkoxy complexes, fully characterized by X‐ray diffraction and magnetic studies, exhibit exceptional photocatalytic efficiency. Quantum chemical studies reveal that the energy barrier for C─C bond cleavage and formation is reduced to below 10 kcal · mol −1 under visible light excitation. This work introduces a new mechanistic paradigm for uranium‐based photocatalysis and positions U(IV) alkoxy complexes as a versatile platform for bond activation and functionalization, expanding the potential applications of depleted uranium in synthetic chemistry.