Electrochemical C-H bond activation via cationic iridium hydride pincer complexes

A C-H bond activation strategy based on electrochemical activation of a metal hydride is introduced. Electrochemical oxidation of ( PCP)IrH₄ ( PCP is [1,3-( Bu₂PCH₂)-C₆H₃]^-) in the presence of pyridine derivatives generates cationic Ir hydride complexes of the type [( PCP)IrH(L)]⁺ (where L = pyridine, 2,6-lutidine, or 2-phenylpyridine). Facile deprotonation of [( PCP)IrH(2,6-lutidine)]⁺ with the phosphazene base tert-butylimino-tris(pyrrolidino)phosphorane, BuP₁(pyrr), results in selective C-H activation of 1,2-difluorobenzene (1,2-DFB) solvent to generate ( PCP)Ir(H)(2,3-C₆F₂H₃). The overall electrochemical C-H activation reaction proceeds at room temperature without need for chemical activation by a sacrificial alkene hydrogen acceptor. This rare example of undirected electrochemical C-H activation holds promise for the development of future catalytic processes.