A Mechanistic Study of the Samarium(II)-Mediated Reduction of Aryl Nitro Compounds to the Corresponding Arylamines. The Crystal Structures of {Sm[N(SiMe3)2]2(thf)}2(μ2-O) and [(Me3Si)2N]2Sm(thf)(μ-PhNNPh)Sm[N(SiMe3)2]2

Treatment of nitrobenzene and other various nitroarenes with 6 equiv of samarium(II) under strictly anhydrous conditions allows for the isolation of aniline or the corresponding arylamine. Reducing the number of samarium(II) equivalents allows for the isolation of intermediate species, e.g., azoarenes or hydrazines. Use of Sm[N(SiMe3)2]2, in place of the typically used SmI2, has allowed for the detailed examination of the aqueous and nonaqueous species formed in this reduction and has been instrumental in delineation of the stepwise reaction mechanism. This is the first time that the reaction intermediates of an organic reaction mediated by samarium(II) have been isolated and analyzed by 1H NMR and X-ray crystallography.