Nitrogenase substrates as intercluster bridging units between the molybdenum atoms in doubly bridged, double cubanes. The synthesis and characterization of the [MoFe3S4Cl2(Cl4cat)]2(.mu.2-S)(.mu.2-L)]n- anions (L = N2H4, n = 4; L = CN-, n = 5)
Nitrogenase substrates as intercluster bridging units between the molybdenum atoms in doubly bridged, double cubanes. The synthesis and characterization of the [MoFe3S4Cl2(Cl4cat)]2(.mu.2-S)(.mu.2-L)]n- anions (L = N2H4, n = 4; L = CN-, n = 5)
复制标题
固氮酶底物作为双桥、双立方烷中钼原子之间的簇间桥接单元。
DOI：
10.1021/ja00179a068
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
D. Coucouvanis
中科院分区：
文献类型：
--
作者：
P. Challen;S. Koo;C. G. Kim;W. Dunham;D. Coucouvanis
二氮的酶还原为氨是由氮酶催化的，并与结构未知的多金属Fe/Mo/S位点1·2密切相关。该位点的Fe: Mo: S组成约为7 - 1∶1∶8 - 2，Mo4和Fe5的EXAFS分析表明，该位点可能含有Fe-(M2-S) 2-Fe和Mo-(^ 2-S) 2-Fe菱形结构亚基。尽管近年来进行了广泛的研究，但合成一种可接受的结构类似物来代替氮化酶Fe/Mo/S位点仍然是一个重要的未完成的目标。最近发现的含有钒和铁代替钼的新氮酶体系促使我们寻找一种具有共同Fe/S结构框架的合成类似物，这种结构框架能够在一个位点容纳不同的金属，并且适合于氮酶底物的双金属活化。包含已知的Fe4S4和MFe3S4亚基（= Mo， V）耦合在Fe-(u2-S)-Fe中，单桥双cubane10 11·”的复合簇将符合这些提出的要求。我们尝试获得这种簇的初步结果已在最近的通讯中报道，其中描述了单桥和双桥“双立方”的合成和结构表征。这些团簇的核心由两个[MFe3S4]立方单元组成，由一个Fe-(/z2-S)-Fe桥（= Fe）耦合或由Fe-(u2-S)-Fe和Mo-(m2-L)-Mo （L= S2~， OH”）桥耦合。本文报道了两种新型双桥双分子的合成和表征
The enzymatic reduction of dinitrogen to ammonia is catalyzed by the nitrogenase enzymes' and is intimately associated with a multimetallic Fe/Mo/S site1· 2 of unknown structure. This site is characterized by an approximate Fe: Mo: S composition3 of 7 ą 1: 1: 8 ą 2, and as indicated by Mo4 and Fe5 EXAFS analyses it may contain Fe-(M2-S) 2-Fe and Mo-(^ 2-S) 2-Fe rhombic structural subunits. In spite of extensive studies in recent years, 6· 7 the synthesis of an acceptable structural analogue for the nit-rogenase Fe/Mo/S site still remains an important unfulfilled goal. The recent discoveries of new nitrogenase systems that contain vanadium8 and perhaps iron9 in place of molybdenum prompted us to search for a synthetic analogue with a common Fe/S structural framework capable of accommodating different metals at one site and suitable in the bimetallic activation of nitrogenase substrates. A composite cluster that contains the known Fe4S4 and MFe3S4 subunits (= Mo, V) coupled in a Fe-(u2-S)-Fe, singly bridged double cubane10 11·" would be in compliance with these proposed requirements. Preliminary results of our attempts to obtain such clusters were reported in recent communications where the synthesis and structural characterization of singly bridged10 and doubly bridged" double cubanes have been de-scribed. These clusters have cores that consist of two [MFe3S4] cubane units coupled by either one Fe-(/z2-S)-Fe bridge (= Fe) or doubly coupled by the Fe-(u2-S)-Fe and Mo-(m2-L)-Mo (L= S2~, OH") bridges. In this communication we report on the synthesis and characterization of two new doubly bridged double