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

Abstract

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 [N₂P₂^tolyl] (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(μ-H)₂ (6). Reduction of 1 and 2 results in the formation of the new bridging dinitrogen complexes ([N₂P₂]Mn)₂(μ-N₂) (7) and ([N₂P₂]Fe)₂(μ-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 [N₂P₂^tolyl]FeCl (10) was isolated following the substitution of [N₂P₂^tolyl] for [N₂P₂]. Reduction of 10 in the presence of N₂ resulted in the formation of the dinitrogen free adduct [N₂P₂^tolyl]Fe (11).