Synthesis and characterization of manganese and iron complexes supported by multidentate [N2P2] ligands.

The coordination chemistry of mono- and divalent manganese and iron complexes supported by the monoanionic multidentate ligands, [N2P2] (where [N2P2] = tBuN(-)SiMe2N(CH2CH2PiPr2)2) and [N2P2tolyl] (where [N2P2 tolyl] = MeC6H4N(-)SiMe2(CH2CH2PiPr2)2) is presented. The Mn(II) and Fe(II) halide complexes [N2P2]MnCl (1) and [N2P2]FeCl (2) serve as precursors to the alkyl and hydride species [N2P2]MnMe (3), [N2P2]FeMe (4), [N2P2]FeCH2SiMe3 (5), and ([N2P2]Mn)2(mu-H)2 (6). Reduction of 1 and 2 results in the formation of the new bridging dinitrogen complexes ([N2P2]Mn)2(mu-N2) (7) and ([N2P2]Fe)2(mu-N2) (8), respectively. Upon exposure to vacuum, N2 is abstracted from 8, resulting in the observed Fe(I) complex, [N2P2]Fe (9). The new Fe(II) halide complex [N2P2tolyl]FeCl (10) was isolated following the substitution of [N2P2tolyl] for [N2P2]. Reduction of 10 in the presence of N2 resulted in the formation of the dinitrogen free adduct [N2P2tolyl]Fe (11).