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.