Dinitrogen Functionalization Affording Chromium Diazenido and Side-on η²‑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-η1:η1-N2)(η1-N2)-Cr(I) 3 and (η1-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 η2-hydrazido complex 6. Protonation of 6 led to the quantitative formation of N2H4. Moreover, the [η2-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.二氮功能化过程中关键中间体配合物的分离，对于阐明其反应机理细节与后续研究至关重要。本文报道了由五甲基环戊二烯基（Cp*，即C₅Me₅）与氮杂环卡宾（NHC）配体稳定的(μ-η¹:η¹-N₂)(η¹-N₂)-Cr(I)配合物3，以及(η¹-N₂)₂-Cr(0)配合物4的合成与表征。将Cr(0)-N₂配合物4与卤代硅烷进行进一步功能化反应，得到了交替反应路径中的关键中间体：重氮亚铬配合物5与侧式η²-肼基亚铬配合物6。对配合物6进行质子化反应，可定量生成肼（N₂H₄）。此外，配合物6中的[η²-Me₃SiNNSiMe₃]²⁻单元，可分别与二氧化碳（CO₂）和叔丁基异氰酸酯（tBuNCO）发生N-C键形成反应，得到相应的N,O-螯合肼基亚铬配合物7与8。