Outlook of nitrogen fixation by carbene

From the first N 2 -metal complex discovered in the 1960s to the borylene N-2 complex reported very recently, chemists have been trying to activate N-2 under milder conditions by investigating many approaches or strategies. Among them, carbene species has been considered a good choice to construct N-C bond to obtain N-containing organic compounds directly. Since the first glimpse of the N-2 exchange of diazomethane, chemists have obtained a deeper understanding of the rebound reaction between carbene and N-2. This review mainly summarizes the progress in the field of N-2 fixation by using carbene species, both experimentally and theoretically. We believe this review will provide readers with an indepth understanding of the state-of-the-art and perspectives of future research particularly in the use of carbene species for activation and transformation of N-2 into N-C containing organic compounds. (C) 2020 Elsevier Ltd. All rights reserved.