N2 fixation by Nature, which is a crucial process to supply bio-available forms of nitrogen, is performed by nitrogenase. This enzyme employs a unique transition metal-sulfur-carbon cluster as its active-site cofactor ([(R-homocitrate)MoFe7S9C], FeMoco), 1,2 and the sulfur-surrounded Fe atoms have been postulated to capture and reduce N2. [3][4][5][6] Whereas synthetic counterparts of FeMoco, metal-sulfur clusters, have displayed binding of N2 in a few examples, 7,8 the reduction of N2 by any synthetic metal-sulfur clusters or even by the extracted form of FeMoco 9 have remained elusive despite a near-50-year history of research. Here we show that the Fe atoms in our synthetic [Mo3S4Fe] cubes 10,11 capture an N2 molecule and catalyze N2 silylation to form N(SiMe3)3 under treatment with excess Na and Me3SiCl. These results exemplify the first catalytic N2 reduction by a synthetic metal-sulfur cluster with an Fe center supported only by S ligands. This work demonstrates the N2-reducing capability of Fe atoms in a S-rich environment, which Nature has selected to accomplish a similar purpose. This work also suggests some critical features for successful N2 reduction by metal-sulfur compounds, which serve as clues to understand the origin of N2 fixation on Earth.

His research interests include organometallic chemistry and bioinorganic chemistry with an emphasis on developing new synthetic methodologies for inorganic molecules.