Synthesis and Photocatalytic sp3 C-H Bond Functionalization of Salen-Ligand-Supported Uranyl(VI) Complexes

Recent years have seen increasing interest in uranyl(VI) photocatalysis. In this study, uranyl complexes were successfully synthesized from ligands <bold>L1</bold>-<bold>L6</bold> and UO2(NO3)(2)<middle dot>6H(2)O under reflux conditions, yielding products <bold>1</bold>-<bold>6</bold> with yields ranging from 30% to 50%. The complexes were thoroughly characterized using NMR spectroscopy, single-crystal X-ray diffraction, and elemental analysis. The results indicate that complexes <bold>1</bold>-<bold>5</bold> possess a pentagonal bipyramidal geometry, whereas complex <bold>6</bold> exhibits an octahedral structure. The photocatalytic properties of these novel complexes for sp(3) C-H bond functionalization were explored. The results demonstrate that complex <bold>4</bold> functions as an efficient photocatalyst for converting C-H bonds to C-C bonds via hydrogen atom transfer under blue light irradiation.