Sulfur bridging interactions of cis-planar NiII-S2N2 coordination units with nickel(II), copper(I,II), zinc(II), and mercury(Il):: A library of bridging modes, including NiII(μ2-SR)2MI,II rhombs
Sulfur bridging interactions of cis-planar NiII-S2N2 coordination units with nickel(II), copper(I,II), zinc(II), and mercury(Il):: A library of bridging modes, including NiII(μ2-SR)2MI,II rhombs
复制标题
DOI：
10.1021/ic040055s
复制
发表时间：
2004-09-20
影响因子：
4.6
通讯作者：
Holm, RH
中科院分区：
文献类型：
--
作者：
Rao, PV;Bhaduri, S;Holm, RH
通过合成和X-射线晶体结构分析，研究了3种顺式平面Ni-II-S2N_2配合物与Ni-II、Cu-I、Cu-II、Zn-II和Hg-II反应物之间的硫桥作用。这项工作受到一氧化碳脱氢酶/乙酰辅酶A合酶A-簇最近的晶体结构的刺激。这种桥联生物组装具有最小的配方[Fe4S4]-(mu(2)-S-Cys)-[M((mu(2)-S-Cys)(2)GIy)Ni]，其中M=Ni-II、Cu-I和Zn-II分别位于铁-硫簇的远端和近端。通过络合物[Ni-II(L-H-S_2N_2)](2-)和[Ni-II(L-R-S_2N_2)]的反应，寻找了由远端镍中心的表示支撑的桥，具有5-5-5个络合环型。反应产物涉及多种分子结构中的Ni-(Mu(2)-S)(1，2)-M桥，其中一些具有以前未知的桥原子连接性。最常见的桥联单元是非平面菱形结构的Ni(Mu(2)-S)(2)M，它包含给定络合物的两个硫原子。那些含有M=Ni-II的化合物具有生物学意义，因为近端的催化金属是镍。合成了具有6-5-5环状结构和镍远端配位球状结构的配合物[Ni(L-655)](2-)，并对其结构进行了表征。结果表明，Ni-2(Mu(2)-S)(2)以[{Ni(L-655)}(2)Ni](2-)和[{Ni(L-655)}Ni(R_2PCH_2CH_2PR2)](R=Et，Ph)的三核[{Ni(L-655)}}Ni(R_2PCH_2CH_2PR2)](R=Et，Ph)的形式存在。总结了Ni-II-S_2N_2络合物的桥联作用，并考虑了这些络合物中Ni-2(Mu(2)-S)(2)菱形的几何特征，它与环型有关(L-H-S_2N_2=N，N‘-亚乙基双(2-巯基异丁酰胺)(4-)；L-R-S_2N_2=反式-rac-N，N’-bis(2-mercapto-2-methylprop-1-yl)-1，2-cyclohexanediamine(2-)；L-655=N-(2-mercaptopropyl)N‘-(2’-mercaptoethyl)glycinamide(4-)).
Sulfur bridging interactions between three cis-planar Ni-II-S2N2 complexes and Ni-II, Cu-I,Cu-II, Zn-II, and Hg-II reactants were investigated by synthesis and X-ray crystal structures of some 24 complexes. This work was stimulated by recent crystallographic structures of the A-cluster of carbon monoxide dehydrogenase/acetylcoenzyme A synthase. This bridged biological assembly has the minimal formulation [Fe4S4]-(mu(2)-S-Cys)-[M((mu(2)-S-Cys)(2)GIy)Ni] with M = Ni-II, Cu-I, and Zn-II at sites distal and proximal, respectively, to the iron-sulfur cluster. Bridges supported by representations of the distal nickel site were sought by reactions of the complexes [Ni-II(L-H-S2N2)](2-) and [Ni-II(L-R-S2N2)], with 5-5-5 chelate ring patterns. Reaction products implicate the bridges Ni-(mu(2)-S)(1,2)-M in a variety of molecular structures, some with previously unknown connectivities of bridge atoms. The most frequently encountered bridge units are the nonplanar rhombs Ni(mu(2)-S)(2)M involving both sulfur atoms of a given complex. Those with M = Ni-II are biologically relevant inasmuch as the catalytic metal at the proximal site is nickel. The complex [Ni(L-655)](2-), containing the 6-5-5 ring pattern and coordination sphere of the distal nickel site, was prepared and structurally characterized. It was shown to sustain Ni-2(mu(2)-S)(2) rhombic interactions in the form of trinuclear [{Ni(L-655)}(2)Ni](2-) and [{Ni(L-655)}Ni(R2PCH2CH2PR2)] (R = Et, Ph) in which the second Ni-II simulates the proximal site. Bridging interactions of Ni-II-S2N2 complexes are summarized, and geometrical features of Ni-2(mu(2)-S)(2) rhombs in these complexes, as dependent on ring patterns, are considered (L-H-S2N2 = N,N'-ethylenebis(2-mercaptoisobutyramide)(4-); L-R-S2N2 = trans-rac-N,N'-bis(2-mercapto-2-methylprop-1-yl)-1,2-cyclohexanediamine (2-); L-655 = N-(2-mercaptopropyl)N'-(2'-mercaptoethyl)glycinamide(4-)).