Scandium-Promoted Direct Conversion of Dinitrogen into Hydrazine Derivatives via N–C Bond Formation

• Published in: Journal of the American Chemical Society 2019-06, Vol.141 (22), p.8773-8777
• Main Authors: Lv, Ze-Jie, Huang, Zhe, Zhang, Wen-Xiong, Xi, Zhenfeng
• Format: Article
• Language: English
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/jacs.9b04293

Direct conversion of dinitrogen (N2) into organic compounds, not through ammonia (NH3), is of great significance both fundamentally and practically. Here we report a highly efficient scandium-mediated synthetic cycle affording hydrazine derivatives (RMeN–NMeR′) directly from N2 and carbon-based electrophiles. The cycle includes three main steps: (i) reduction of a halogen-bridged discandium complex under N2 leading to a (N2)3–-bridged discandium complex via a (N2)2– intermediate; (ii) treatment of the (N2)3– complex with methyl triflate (MeOTf), affording a (N2Me2)2–-bridged discandium complex; and (iii) further reaction of the (N2Me2)2– complex with the carbon-based electrophile, producing the hydrazine derivative and regenerating the halide precursor. Furthermore, insertion of a CO molecule into one Sc–N bond in the (N2Me2)2––scandium complex was observed. Most notably, this is the first example of rare-earth metal-promoted direct conversion of N2 to organic compounds; the formation of C–N bonds by the reaction of these (N2)3– and (N2Me2)2– complexes with electrophiles represents the first case among all N2–metal complexes reported.