Theory of chemical bonds in metalloenzymes V: Hybrid‐DFT studies of the inorganic [8Fe–7S] core
Theory of chemical bonds in metalloenzymes V: Hybrid‐DFT studies of the inorganic [8Fe–7S] core
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金属酶中的化学键理论 V：无机 [8Fe-7S] 核的混合 DFT 研究
DOI：
10.1002/qua.21201
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发表时间：
2006
影响因子：
2.2
通讯作者：
K. Tatsumi
中科院分区：
文献类型：
--
作者：
M. Shoji;K. Koizumi;Y. Kitagawa;S. Yamanaka;M. Okumura;K. Yamaguchi;Y. Ohki;Y. Sunada;M. Honda;K. Tatsumi
用密度泛函UB 3LYP和UBLYP方法研究了[8 Fe-7S]无机模型配合物（1）的电子结构和自旋结构. 1的实验几何被用来计算自旋哈密顿模型内Fe-自旋中心之间的交换相互作用（J值）。根据计算的J值，很好地再现了实验的随温度变化的顺磁性。计算得到的低能级也与实验结果一致。这表明1的基态自旋是单线态（S = 0），因为两个[4Fe-3S]立方烷单元之间存在弱反铁磁耦合，它们具有Fe（III）Fe（II）3形式电荷和S = 7/2自旋态。最稳定的破缺对称（BS）解决方案的一阶密度矩阵已对角化，以阐明自然分子轨道（MO）和他们的占领数为1，这是很难得到的适应（SA）CASSCF方法。利用占据数计算了自旋投影前后的有效键级等化学指标，得到了1的不稳定化学键的分子轨道图。结果表明，对于多核过渡金属团簇，BS MO计算结合自旋投影SA分析是CASSCF MO方法的一种有效和实用的替代方法。© 2006 Wiley Periodicals，Inc.国际量子化学杂志，2006年
The electronic and spin structures of the [8Fe–7S] inorganic model complex (1) have been investigated using the density functional theory (DFT) UB3LYP and UBLYP methods. The experimental geometry of 1 was used to calculate the sets of exchange interactions (J values) between Fe-spin centers within spin Hamiltonian models. The experimental temperature-dependent paramagnetism is well reproduced on the basis of the calculated J values. The calculated low-lying energy levels are also consistent with those of the experiments. This indicates that the ground spin state of 1 is singlet (S = 0) for the weak antiferromagnetic coupling between two [4Fe–3S] cubane units, which take the Fe(III)Fe(II)3 formal charge and S = 7/2 spin states. The first-order density matrix of the most stable broken-symmetry (BS) solution has been diagonalized to elucidate the natural molecular orbitals (MOs) and their occupation number of 1, which are hardly obtained by the symmetry-adapted (SA) CASSCF approach. Several chemical indices such as the effective bond orders before and after spin projection are also calculated by using the occupation numbers to provide the SA MO picture of labile chemical bonds of 1. It is found that the BS MO calculation followed by spin-projected SA analysis is an effective and practical alternative to the CASSCF MO approach for the multinuclear transition metal clusters. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
影响因子：
56.9
作者：
Beinert, H;Holm, RH;Munck, E
通讯作者：
Munck, E
影响因子：
2.9
作者：
Peters, JW;Stowell, MHB;Rees, DC
通讯作者：
Rees, DC