Well-Defined Aryl-Fe(II) Complexes in Cross-Coupling and C–H Activation Processes

[Image: see text] Herein we explore the intrinsic organometallic reactivity of iron embedded in a tetradentate N(3)C macrocyclic ligand scaffold that allows the stabilization of aryl-Fe species, which are key intermediates in Fe-catalyzed cross-coupling and C–H functionalization processes. This study covers C–H activation reactions using (Me)L(H) and FeCl(2), biaryl C–C coupling product formation through reaction with Grignard reagents, and cross-coupling reactions using (Me)L(Br) or (H)L(Br) in combination with Fe(0)(CO)(5). Synthesis under light irradiation and moderate heating (50 °C) affords the aryl-Fe(II) complexes [Fe(II)(Br)((Me)L)(CO)] (1(Me)) and [Fe(II)((H)L)(CO)(2)]Br (1(H)). Exhaustive spectroscopic characterization of these rare low-spin diamagnetic species, including their crystal structures, allowed the investigation of their intrinsic reactivity.