Intramolecular C−H Activation by Putative Terminal Two-Coordinate Manganese(III) Imido Intermediates: Hydrogen Abstraction from a Phenyl Group

Reactions of the Mn(I) inverted sandwich complex (η6-C7H8){MnAr*-3,5-iPr2}2 (Ar*-3,5-iPr2 = C6H-2,6-(C6H2-2,4,6-iPr3)2-3,5-iPr2) with bulky terphenyl azides afforded the dimeric Mn(II) amido/aryl complex {CH2C6H2-2-(C6H3-2-(N(H)MnAr*-3,5-iPr2)-3-(C6H2-2,4,6-Me3))-3,5-Me2}2 (1) and the binuclear Mn(II) complex (μ,η1:η1-NH-C6H3-2-(C6H2-3,5-tBu2)-6-(C6H3-3,5-tBu2)){MnAr*-3,5-iPr2}2 (2). Complex 1 arises via methyl hydrogen abstraction by the nitrogen atom and dimerization via radical coupling with C−C bond formation. Complex 2 was formed by phenyl hydrogen abstraction by the imido nitrogen atom, followed by incorporation of a further MnAr*-3,5-iPr2 unit. In addition, complex 2 features two different manganese environments and is also the first structurally characterized heteroleptic two-coordinate diaryl Mn(II) species.