Synthetic nitrogen fixation with mononuclear molybdenum complexes: Electronic-structural and mechanistic insights from DFT

Synthetic nitrogen fixation continues to be a topic of high interest. Besides the synthesis and mechanistic investigation of small-molecule model systems of nitrogenase, quantum chemical studies are required to provide a mechanistic understanding and help in the design of new systems. This article revisits DFT treatments of existing mononuclear Mo(0) pentaphosphine-based model complexes. Moreover, it considers a recently published Mo(0)-N2 complex coordinated by a pentadentate phosphine ligand. This complex as well as its possible role in the conversion from N2 to NH3 are thoroughly analyzed by DFT and its properties are compared to those of other molybdenum pentaphosphine systems. Also a proposition is made for another target complex showing even more promise regarding the catalytic fixation of nitrogen.