Dinitrogen Functionalization Affording Chromium Diazenido and Side-on?2-Hydrazido Complexes

Isolation of key intermediate complexes in dinitrogen functionalization is crucial for elucidating the mechanistic details and further investigation. Herein, the synthesis and characterization of (mu-11:11-N2)(11-N2)-Cr(I) 3 and (11-N2)2-Cr(0) complexes 4 supported by Cp* (Cp* = C5Me5) and NHC ligands were reported. Further functionalization of Cr(0)-N2 complex 4 with silyl halides delivered the key intermediates in the alternating pathway, the chromium diazenido complex 5 and the chromium side-on 12-hydrazido complex 6. Protonation of 6 led to the quantitative formation of N2H4. Moreover, the [12-Me3SiNNSiMe3]2- unit in 6 enabled N-C bond formation reactions with CO2 and tBuNCO, giving the corresponding N,O-chelating hydrazidochromium complexes 7 and 8, respectively.