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

A single molecular rhodium catalyst system (PC2-CpRh) 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-CpRh) 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.