Reaction of M(II) Diaryls (M = Mn or Fe) with Ammonia to Afford Parent Amido Complexes

The reaction of the two-coordinate diaryls MAr′₂ (M = Mn or Fe; Ar′ = C₆H₃-2,6-(C₆H₃-2,6-ⁱPr₂)₂) with excess NH₃ below room temperature afforded the parent amido complexes {Ar′Mn(μ-NH₂)(NH₃)}₂ (1) and {Ar′Fe(μ-NH₂)}₂ (2) in good yields. The reactions were accompanied by elimination of the arene Ar′H. Both complexes were obtained as dimers in which the metals are bridged by two NH₂ ligands. The complex 1 also includes an ammonia (NH₃) ligand bound to each manganese. Ammonia complexation did not occur in 2, and the metals remained three-coordinate. The metal electron configurations are high-spin and antiferromagnetically coupled.