Reactivity toward Unsaturated Small Molecules of Thiolate-Bridged Diiron Hydride Complexes.
Reactivity toward Unsaturated Small Molecules of Thiolate-Bridged Diiron Hydride Complexes.
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DOI：
10.1021/acs.inorgchem.8b02459
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发表时间：
2018-11
影响因子：
4.6
通讯作者：
Dawei Yang;Sunlin Xu;Yixin Zhang;Ying Li;Yang Li;Baomin Wang;Jingping Qu
中科院分区：
文献类型：
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作者：
Dawei Yang;Sunlin Xu;Yixin Zhang;Ying Li;Yang Li;Baomin Wang;Jingping Qu
在1当量的tBuNC存在下，二铁末端氢化物配合物[Cp*Fe(t-H)(μ-η2：η4-bdt)FeCp*][BF4](1[BF4])中FeIII-H键的均相裂解顺利进行，释放出1/2H2，随后tBuNC基团与不饱和FeII中心结合。有趣的是，当1[BF4]暴露于乙炔的1 atm时，氢化物配体从末端到桥联配位的异构化过程没有受到影响。当二铁氢化物桥联化合物2[BF4]与乙炔在30°C反应时，两个FeIII-H键被打断，然后乙炔分子以一种新颖的μ-η2：η2侧向方式配位到双铁中心。在上述反应体系中，无论是末端还是桥联的氢化物配体都起到了电子供体的作用，促进了双铁中心从FeIFeIII还原到FeIIFeII。这些反应模式使人想起固氮酶催化循环中负责氮气结合和氢气释放的关键E4状态，该状态包含两个{Fe-H-Fe}基序作为铁中心还原的电子储存库。不同的是，当用TM N3处理1[BF4]时，末端氢化物配体被插入叠氮基团，以适中的产率得到二铁酰胺络合物4[BF4]。
In the presence of 1 equiv of tBuNC, the homolytic cleavage of the FeIII-H bond in the diiron terminal hydride complex [Cp*Fe( t-H)(μ-η2:η4-bdt)FeCp*][BF4] (1[BF4]) smoothly took place to release 1/2 H2, followed by binding of a tBuNC group to the unsaturated FeII center. Interestingly, upon exposure of 1[BF4] to 1 atm of acetylene, the isomerization process of the hydride ligand from the terminal to bridging coordination site was unaffected. Upon treatment of the diiron hydride bridged complex 2[BF4] with acetylene at 30 °C, two FeIII-H bonds were broken, and then an acetylene molecule was coordinated to the diiron centers in a novel μ-η2:η2 side-on fashion. In the above reaction system, the hydride ligands whether terminal or bridging all play a role as the electron donor for the reduction of the diiron centers from FeIIIFeIII to FeIIIFeII. These reaction patterns are reminiscent of the vital E4 state responsible for N2 binding and H2 liberation in the catalytic cycle of nitrogenase, which contains two {Fe-H-Fe} motifs as electron reservoirs for the reduction of the iron centers. Differently, when treating 1[BF4] with TMSN3, the terminal hydride ligand was inserted into the azide group to give a diiron amide complex 4[BF4] in moderate yield.