Electrochemical C–H bond activation via cationic iridium hydride pincer complexes. Issue 40 (28th August 2019) - Lindley, Brian M.
Abstract : Electrochemical C–H activation proceeds at room temperature upon oxidation of a pincer-ligated iridium complex in the presence of base. Abstract : A C–H bond activation strategy based on electrochemical activation of a metal hydride is introduced. Electrochemical oxidation of ( t Bu4 PCP)IrH4 ( t Bu4 PCP is [1, 3-( t Bu2 PCH2 )-C6 H3 ] − ) in the presence of pyridine derivatives generates cationic Ir hydride complexes of the type [( t Bu4 PCP)IrH(L)] + (where L = pyridine, 2, 6-lutidine, or 2-phenylpyridine). Facile deprotonation of [( t Bu4 PCP)IrH(2, 6-lutidine)] + with the phosphazene base tert -butylimino-tris(pyrrolidino)phosphorane, t BuP1 (pyrr), results in selective C–H activation of 1, 2-difluorobenzene (1, 2-DFB) solvent to generate ( t Bu4 PCP)Ir(H)(2, 3-C6 F2 H3 ). 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.