Rearrangement of symmetrical dicubane clusters into topological analogues of the P cluster of nitrogenase: nature's choice?
Rearrangement of symmetrical dicubane clusters into topological analogues of the P cluster of nitrogenase: nature's choice?
复制标题
DOI：
10.1021/ja0279702
复制
发表时间：
2002-11
影响因子：
15
通讯作者：
Yugen Zhang;J. Zuo;Hongcai Zhou;Richard H. Holm
中科院分区：
文献类型：
--
作者：
Yugen Zhang;J. Zuo;Hongcai Zhou;Richard H. Holm
反应方案已经开发，导致簇具有氮酶的PN簇的拓扑结构。单立方体簇[(Tp)MFe3S4Cl3]z （M = Mo, z = 1-; M = V, z = 2-）与PEt3反应生成[(Tp)MFe3S4(PEt3)3]1+，并还原为具有高度还原（2[MFe3S4]1+）核的中性边桥双立方体[(Tp)2M2Fe6S8(PEt3)4]。这些团簇在乙腈中与（Et4N）（HS）反应生成[(Tp)2Mo2Fe6S9(SH)2]3-和[(Tp)2V2Fe6S9(SH)2]4-。Et4N+盐的x射线结构显示出M2Fe6(mu2-S)2(mu3-S)6（mu6-S）的桥接模式，其中两个立方体MFe3(mu3-S)3单元共享共同的桥接原子mu6-S，并在外部由两个mu2-S原子桥接。M位具有三角八面体配位，Fe位具有畸变四面体配位。在蛋白质结合簇Fe8S7(mu2-SCys)2(SCys)4中，氢硫化物配体和硫化物原子分别模拟末端半胱氨酸连接和mu2桥。合成簇具有与PN簇相同的桥接模式，并与PN簇接近一致。这些簇是PN簇的第一个分子拓扑类似物。与后者一样，它们也被大量还原（大部分是铁（II））。
Reaction schemes have been developed that lead to clusters having the topology of the PN cluster of nitrogenase. The single cubane clusters [(Tp)MFe3S4Cl3]z (M = Mo, z = 1-; M = V, z = 2-) react with PEt3 to give [(Tp)MFe3S4(PEt3)3]1+, which are reduced to the neutral edge-bridged double cubanes [(Tp)2M2Fe6S8(PEt3)4] with highly reduced (2[MFe3S4]1+) cores. Reaction of these clusters in acetonitrile with (Et4N)(HS) results in the formation of [(Tp)2Mo2Fe6S9(SH)2]3- and [(Tp)2V2Fe6S9(SH)2]4-. X-ray structures of the Et4N+ salts reveal the bridging pattern M2Fe6(mu2-S)2(mu3-S)6(mu6-S) in which two cuboidal MFe3(mu3-S)3 units share the common bridge atom mu6-S and are externally bridged by two mu2-S atoms. The M sites possess trigonal octahedral, and the Fe sites, distorted tetrahedral coordination. Hydrosulfide ligands and sulfide atoms simulate terminal cysteinate ligation and mu2 bridges, respectively, in the protein-bound cluster Fe8S7(mu2-SCys)2(SCys)4. The synthetic clusters have the same bridging pattern as the PN cluster and approach congruency with it. These clusters are the first molecular topological analogues of a PN cluster. Like the latter, they are substantially reduced (majority of Fe(II)).