Facile hydrogen atom abstraction and sulfide formation in a methyl-thiolate capped iron–sulfur–carbonyl cluster
Facile hydrogen atom abstraction and sulfide formation in a methyl-thiolate capped iron–sulfur–carbonyl cluster
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在硫醇甲酯封端的铁硫羰基簇中轻松提取氢原子并形成硫化物
DOI：
10.1039/c9dt04098f
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发表时间：
2020
影响因子：
4
通讯作者：
Rose, Michael J.
中科院分区：
文献类型：
--
作者：
Shupp, J. Patrick;Rose, Michael J.
由于自由基SAM反应的广泛相关性，在含铁簇附近或与其结合的甲基C-H键活化中的兴趣具有关键的生物学重要性。具体而言，这些过程涉及固氮酶FeMoco活性位点中发现的间质碳化物的生物发生。在这项工作中，我们发现抗磁性的甲硫醇盐覆盖的铁-羰基簇阴离子[（CH 3S）Fe 3（CO）9]−（1）在用克里思处理后经历了容易的C-H氢原子夺取。该过程导致（i）消除CH 3部分，（ii）形成硫桥，和（iii）簇二聚化-从而产生“三聚体的二聚体”簇[K（benzo-15-crown-5）2]2[（SFe 2（CO）12）2Fe（CO）2]（2）。相反，相应的异丙基变体[Fe 3（SiPr）（CO）9]−（3）不与克里思反应。质谱法证实了TEMPOH的存在，以及CO维斯维斯CO2和2，2，6，6-四甲基哌啶的氧化。顶空的GC-MS测量结果表明，甲基碳的最终命运可能是掺入多种产品，其中之一可能是挥发性低质量烃，而不是碳/碳化物掺入。
The interest in methyl group C–H bond activation near or bound to iron-containing clusters is of key biological importance, due to the broad relevance of radical SAM reactions. Specifically, such processes are implicated in the biogenesis of the interstitial carbide found in the nitrogenase FeMoco active site. In this work, we find that the diamagnetic, methyl-thiolate capped iron–carbonyl cluster anion [(CH3S)Fe3(CO)9]− (1) undergoes facile C–H hydrogen atom abstraction upon treatment with TEMPO. The process leads to (i) eradication of the CH3 moiety, (ii) formation of a sulfide bridge, and (iii) cluster dimerization—thereby generating the ‘dimer of trimers’ cluster [K(benzo-15-crown-5)2]2[(SFe2(CO)12)2Fe(CO)2] (2). In contrast, the corresponding isopropyl variant [Fe3(SiPr)(CO)9]− (3) does not react with TEMPO. Mass spectrometry confirmed the presence of TEMPOH, as well as CO oxidation vis a vis CO2 and 2,2,6,6-tetramethylpiperidine. GC-MS measurements of the headspace reveal that the ultimate fate of the methyl carbon is likely incorporation into multiple products—one of which may be a volatile low mass hydrocarbon—rather than carbon/carbide incorporation.