Nitrogen (N₂) fixation by nature, which is a crucial process for the supply of bio-available forms of nitrogen, is performed by nitrogenase. This enzyme uses a unique transition-metal–sulfur–carbon cluster as its active-site co-factor ([(R-homocitrate)MoFe₇S₉C], FeMoco)^1,2, and the sulfur-surrounded iron (Fe) atoms have been postulated to capture and reduce N₂ (refs. ^3,4,5,6). Although there are a few examples of synthetic counterparts of the FeMoco, metal–sulfur cluster, which have shown binding of N₂ (refs. ^7,8,9), the reduction of N₂ by any synthetic metal–sulfur cluster or by the extracted form of FeMoco¹⁰ has remained elusive, despite nearly 50 years of research. Here we show that the Fe atoms in our synthetic [Mo₃S₄Fe] cubes^11,12 can capture a N₂ molecule and catalyse N₂ silylation to form N(SiMe₃)₃ under treatment with excess sodium and trimethylsilyl chloride. These results exemplify the catalytic silylation of N₂ by a synthetic metal–sulfur cluster and demonstrate the N₂-reduction capability of Fe atoms in a sulfur-rich environment, which is reminiscent of the ability of FeMoco to bind and activate N₂.

固氮 (N ₂ ) 的自然固定是提供生物可利用形式的氮的关键过程，由固氮酶进行。该酶使用独特的过渡金属-硫-碳簇作为其活性位点辅助因子（[( R -homocitrate)MoFe ₇ S ₉ C], FeMoco) ^1,2和硫包裹的铁 (Fe)原子被假定为捕获和还原 N ₂（参考文献^3,4,5,6）。虽然有几个 FeMoco 的合成对应物，金属硫簇的例子，它们显示出 N ₂的结合（参考文献^{7,8,9 ），但 N} ₂的还原尽管进行了近 50 年的研究，但任何合成金属硫簇或 FeMoco ^{10的提取形式仍然难以捉摸。}在这里，我们展示了我们合成的 [Mo ₃ S ₄ Fe] 立方体^11,12中的 Fe 原子在用过量的钠和三甲基氯硅烷处理时可以捕获 N ₂分子并催化 N ₂甲硅烷基化形成 N(SiMe ₃ ) _{3 。}这些结果举例说明了合成金属-硫簇对 N ₂的催化甲硅烷基化，并证明了Fe 原子在富硫环境中的 N _{2还原能力，这让人联想到 FeMoco 结合和活化 N 的能力2} .