大连理工大学曲景平团队报道了硫代桥联二铁络合物使亚硝基苯的N–O键断裂生成磺酰胺类化合物。相关研究成果发表在2021年10月7日出版的国际学术期刊《美国化学会杂志》。

过渡金属配合物促进的亚硝苯活化因其对理解生物过程和催化C–N键形成过程的重要意义而备受关注。尽管在过去几十年中进行了深入的研究，但富电子金属中心通常用于实现配位硝基苯的N–O或C–N键断裂情况是很少的。在该方面，构建一个合适的功能系统来检测其对亚硝基甲苯还原活化的独特反应性是非常重要和具有挑战性的。

该文中，研究人员提出了一种{Fe2S2}功能性平台，该平台可以通过前所未有的铁定向硫氰酸盐插入N–O键来激活亚硝基苯，从而选择性地生成定义良好的二亚铁苯硫酰胺络合物。此外，计算研究表明，在亚硝基苯的协同四电子还原过程中，铁中心起着重要的电子穿梭作用。

值得注意的是，与完整的桥连硝基甲苯配体相比，在单独或组合的质子和还原剂存在下，苯硫酰胺部分优先转化为苯胺，可能意味着硫酰胺物种的形成加速了硝基甲苯的还原过程。该文给出的反应模式代表了一种由硫代桥联二铁络合物实现的亚硝基苯的新活化模式。

附：英文原文

Title: Generation of a Sulfinamide Species from Facile N–O Bond Cleavage of Nitrosobenzene by a Thiolate-Bridged Diiron Complex

Author: Sunlin Xu, Dawei Yang, Baomin Wang, Yifeng Chen, Shengfa Ye, Jingping Qu

Issue&Volume: October 7, 2021

Abstract: The activation of nitrosobenzene promoted by transition-metal complexes has gained considerable interest due to its significance for understanding biological processes and catalytic C–N bond formation processes. Despite intensive studies in the past decades, there are only limited cases where electron-rich metal centers were commonly employed to achieve the N–O or C–N bond cleavage of the coordinated nitrosobenzene. In this regard, it is significant and challenging to construct a suitable functional system for examining its unique reactivity toward reductive activation of nitrosoarene. Herein, we present a {Fe2S2} functional platform that can activate nitrosobenzene via an unprecedented iron-directed thiolate insertion into the N–O bond to selectively generate a well-defined diiron benzenesulfinamide complex. Furthermore, computational studies support a proposal that in this concerted four-electron reduction process of nitrosobenzene the iron center serves as an important electron shuttle. Notably, compared to the intact bridging nitrosoarene ligand, the benzenesulfinamide moiety has priority to convert into aniline in the presence of separate or combined protons and reductants, which may imply the formation of the sulfinamide species accelerates reduction process of nitrosoarene. The reaction pattern presented here represents a novel activation mode of nitrosobenzene realized by a thiolate-bridged diiron complex.

DOI: 10.1021/jacs.1c03542

Source: https://pubs.acs.org/doi/10.1021/jacs.1c03542