Merging Two Functions in a Single Rh Catalyst System: Bimodular Conjugate for Light-Induced Oxidative Coupling

A single molecular rhodium catalyst system (PC2-Cp^#Rh^III) bearing two functional domains for both photosensitization and C–H carbometalation was designed to enable an intramolecular redox process. The hypothesized charge-transfer species (PC2^•–-Cp^#Rh^IV) was characterized by spectroscopic and electrochemical analyses. This photoinduced internal oxidation allows a facile access to the triplet state of the key post-transmetalation intermediate that readily undergoes C–C bond-forming reductive elimination with a lower activation barrier than in its singlet state, thus enabling catalytic C–H arylation and methylation processes.