Multi-Site Reactivity: Reduction of Six Equivalents of Nitrite To Give an Fe6(NO)6 Cluster with a Dramatically Expanded Octahedral Core
Multi-Site Reactivity: Reduction of Six Equivalents of Nitrite To Give an Fe6(NO)6 Cluster with a Dramatically Expanded Octahedral Core
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DOI：
10.1021/ja2052655
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发表时间：
2011-09-07
影响因子：
15
通讯作者：
Betley, Theodore A.
中科院分区：
文献类型：
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作者：
Harris, T. David;Betley, Theodore A.
在质子源存在下，NO2-与八面体簇合物（L-H）（2）Fe-6反应，得到六亚硝酰基簇合物（L-H）（2）Fe-6（NO）（6）。该物种通过质子诱导的每个簇中六个亚硝酸盐分子的还原形成，利用多核核心上的每个可用位点。六亚硝酰基簇的形成伴随着（L-H）（2）Fe-6核体积的近2倍膨胀，其中核内Fe-Fe相互作用被Fe中心和NO配体之间的强π键所克服。这种数量级的核心体积在没有间隙原子支持的八面体金属簇中是罕见的。此外，由（L-H）（2）Fe-6平台提供的结构灵活性突出了涉及具有金属配体多重键的物质的其他反应化学的潜力。在不存在质子源的情况下进行簇[（L-H）（2）Fe-6（NCMe）（6）]（4+）与亚硝酸根的反应用于阻止亚硝酸根还原，并且能够干净地分离中间体六亚硝酰基簇[（L-H）（2）Fe-6（NO2）（6）]（2-）。
Reaction of NO2- with the octahedral cluster (L-H)(2)Fe-6 in the presence of a proton source affords the hexanitrosyl cluster (L-H)(2)Fe-6(NO)(6). This species forms via a proton-induced reduction of six nitrite molecules per cluster, utilizing each site available on the polynuclear core. Formation of the hexanitrosyl cluster is accompanied by a near 2-fold expansion of the (L-H)(2)Fe-6 core volume, where intracore Fe-Fe interactions are overcome by strong pi-bonding between Fe centers and NO ligands. A core volume of this magnitude is rare in octahedral metal clusters not supported by interstitial atoms. Moreover, the structural flexibility afforded by the (L-H)(2)Fe-6 platform highlights the potential for other reaction chemistry involving species with metal ligand multiple bonds. Carrying out the reaction of the cluster [(L-H)(2)Fe-6(NCMe)(6)](4+) with nitrite in the absence of a proton source serves to forestall the nitrite reduction and enables clean isolation of the intermediate hexanitrosyl cluster [(L-H)(2)Fe-6(NO2)(6)](2-).