Bimetallic Cleavage of Aromatic C–H Bonds by Rare-Earth-Metal Complexes

A new type of C–H bond activation mediated by rare-earth metals under reducing conditions is reported. The synergy between reductants and rare-earth-metal complexes allows the cleavage of unactivated aromatic C–H bonds. The reaction between rare-earth-metal iodides supported by a 1,1′-ferrocenediamide ligand and potassium graphite in benzene leads to the formation of a 1:1 metal molar ratio of the corresponding metal hydride and metal phenyl complex. A proposed mechanism involving an inverse sandwich arene bimetallic intermediate is supported by experimental and computational studies.