Derivatization of dinitrogen by molybdenum in triamidoamine complexes

The reduction of [N3N]MoCl by an excess of Mg powder in THF under dinitrogen (1 atm) yields the diazenido species {[N3N] Mo - N=N}(2)Mg(THF)(2) (1), which reacts with MCl2(PPh3)(2) (M = Ni or Pd) or ZnCl2 to yield [N3N]Mo(N-2) (2). Heating toluene solutions of 2 under dinitrogen yields the homobimetallic dinitrogen complex [N3N]Mo-N=N-Mo[N3N] (3). Derivatization of dinitrogen is achieved by reaction of 1 with (TMS)Cl to yield the diazenido complex [N3N]Mo-N=N-TMS (4). 4 reacts with an excess of MeOTf to give two products, the dimethyl hydrazido complex {[N(CH2CH2NSiMe3)(2)(CH2CH2NCH3)]Mo=N-NMe2}OTF (5) and the diazenido complex {[(Me3SiNCH2CH2)(2)NCH2CH2NMe2]Mo-N=NSiMe3} OTf (6). Both 5 and 6 react readily with MeMgCl to yield products arising from methylation at molybdenum, [N(CH2CH2NSiMe3)(2)(CH2CH2NMe2)]Mo(CH3)(N-2-TMS) (7) and [N(CH2CH2NSiMe3)(2)(CH2CH2NMe)]Mo(CH3)(NNMe2) (8), respectively. In 7, the dimethylamino group is not bound to the metal. Compound 8 is thermally unstable, decomposing via N-N bond cleavage to yield the nitrido complex [(Me3SiNCH2CH2)(2)N(CH2CH2NMe)]Mo=N (9). X-ray studies are reported for compounds 1, 2, 5, 6, and 7.