Sulfur K-edge XAS and DFT calculations on [Fe4S4]2+ clusters:: Effects of H-bonding and structural distortion on covalency and spin topology
Sulfur K-edge XAS and DFT calculations on [Fe4S4]2+ clusters:: Effects of H-bonding and structural distortion on covalency and spin topology
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DOI：
10.1021/ic050981m
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发表时间：
2005-11-14
影响因子：
4.6
通讯作者：
Solomon, EI
中科院分区：
文献类型：
--
作者：
Dey, A;Roche, CL;Solomon, EI
本文报道了[Fe_4S_4]（2+）氢键拉长立方体的硫K边X射线吸收谱。数据显示，这种合成立方体的共价性低于没有氢键的普通压缩立方体。DFT计算表明，观察到的电子结构的差异有显着的贡献，从集群扭曲和氢键。发现伸长和压缩的Fe 4S4结构具有不同的自旋拓扑（即，彼此反铁磁耦合的离域Fe2S2子团簇的取向）。这表明，氢键相互作用与counterweight不有助于集团的伸长。一个磁结构的相关性开发的Fe4S4立方体，用于确定氧化还原Fe2S2 subdusters在活性位点的HiPIP和铁氧还蛋白涉及这些集群。
Sulfur K-edge X-ray absorption spectroscopy of a hydrogen-bonded elongated [Fe4S4](2+) cube is reported. The data show that this synthetic cube is less covalent than a normal compressed cube with no hydrogen bonding. DFT calculations reveal that the observed difference in electronic structure has significant contributions from both the cluster distortion and from hydrogen bonding. The elongated and compressed Fe4S4 structures are found to have different spin topologies (i.e., orientation of the delocalized Fe2S2 subclusters which are antiferromagnetically coupled to each other). It is suggested that the H-bonding interaction with the counterion does not contribute to the cluster elongation. A magneto-structural correlation is developed for the Fe4S4 cube that is used to identify the redoxactive Fe2S2 subdusters in active sites of HiPIP and ferredoxin proteins involving these clusters.