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N-Containing organic compounds are of vital importance to lives. Practical synthesis of valuable N-containing organic compounds directly from dinitrogen (N2), not through ammonia (NH3), is a holy-grail in chemistry and chemical industry. An essential step for this transformation is the functionalization of the activated N2 units/ligands to generate N−C bonds. Pioneering works of transition-metal mediated direct conversion of N2 into organic compounds via N−C bond formation at metal dinitrogen [N2-M] complexes have generated diversified coordination modes and laid the foundation of understanding for N−C bond formation mechanism. This review summarizes those major achievements and is organized by the coordination modes of the [N2-M] complexes (end-on, side-on, end-on-side-on, etc.) that are involved in the N−C bond formation steps, and each part is arranged in terms of reaction types (N-alkylation, N-acylation, cycloaddition, insertion, etc.) between [N2-M] complexes and carbon-based substrates. Besides, earlier works on one-pot synthesis of organic compounds from N2 via ill-defined intermediates are also briefed. Although almost all of the syntheses of N-containing organic compounds via direct transformation of N2 so far in the literature are realized in homogeneous stoichiometric thermochemical reaction systems and are discussed here in detail, the sporadically reported syntheses involving photochemical, electrochemical, heterogeneous thermo-catalytic reactions, if any, are also mentioned. This review aims to provide readers with in-depth understanding of the state-of-the-arts and perspectives of future research particularly in direct catalytic and efficient conversion of N2 into N-containing organic compounds under mild conditions, and to stimulate more research efforts to tackle this longstanding and grand scientific challenge.

Direct conversion of dinitrogen (N 2 ) into organic compounds, not through ammonia (NH 3 ), 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 N 2 and carbon-based electrophiles. The cycle includes three main steps: (i) reduction of a halogen-bridged discandium complex under N 2 leading to a (N 2 ) 3− -bridged discandium complex via a (N 2 ) 2− intermediate; (ii) treatment of the (N 2 ) 3− complex with methyl triflate (MeOTf), affording a (N 2 Me 2 ) 2− -bridged discandium complex; and (iii) further reaction of the (N 2 Me 2 ) 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 (N 2 Me 2 ) 2− −scandium complex was observed. Most notably, this is the first example of rare-earth metal-promoted direct conversion of N 2 to organic compounds; the formation of C−N bonds by the reaction of these (N 2 ) 3− and (N 2 Me 2 ) 2− complexes with electrophiles represents the first case among all N 2 − metal complexes reported.