We report the use of a rhodium(II) dimer in visible light photoredox catalysis for the aerobic oxidation of arylboronic acids to phenols under mild conditions. Spectroscopic and computational studies indicate that the catalyst Rh 2 (bpy) 2 (OAc) 4 (1) undergoes metal−metal to ligand charge transfer upon visible light irradiation, which is responsible for catalytic activity. Further reactivity studies demonstrate that 1 is a general photoredox catalyst for diverse oxidation reactions.

Well-defined dinuclear silver­(I) complexes have been targeted for applications in catalysis and materials chemistry, and the effect of close silver–silver interactions on electronic structure remains an area of active inquiry. In this study, we describe the synthesis, structure, and photophysical properties of dimeric silver complexes featuring a redox-active naphthyridine diimine ligand. Unusually for silver­(I), these complexes display absorption features in the visible region due to metal–metal to ligand charge transfer (MMLCT) transitions, which arise from the combination of close silver–silver interactions and low-lying ligand π* orbitals. The complexes’ photophysical properties are explored via a combination of spectroscopic and computational studies, revealing MMLCT excited state lifetimes that exceed 1 μs. These results portend previously unforeseen applications of silver­(I) dimers in visible light absorption and excited state reactivity.