Dinitrogen Functionalization Affording Chromium Diazenido and Side-on η 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 (μ-η 1 :η 1 -N 2 )(η 1 -N 2 )-Cr(I) 3 and (η 1 -N 2 ) 2 -Cr(0) complexes 4 supported by Cp* (Cp* = C 5 Me 5 ) and NHC ligands were reported. Further functionalization of Cr(0)-N 2 complex 4 with silyl halides delivered the key intermediates in the alternating pathway, the chromium diazenido complex 5 and the chromium side-on η 2 -hydrazido complex 6 . Protonation of 6 led to the quantitative formation of N 2 H 4 . Moreover, the [η 2 -Me 3 SiNNSiMe 3 ] 2- unit in 6 enabled N-C bond formation reactions with CO 2 and t BuNCO, giving the corresponding N , O -chelating hydrazidochromium complexes 7 and 8 , respectively.