Spin‐inversion mechanisms in O2 binding to a model heme complex revisited by density function theory calculations
Spin‐inversion mechanisms in O2 binding to a model heme complex revisited by density function theory calculations
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DOI：
10.1002/jcc.26159
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发表时间：
2020-02
影响因子：
3
通讯作者：
Kohei Saito;Yuya Watabe;T. Fujihara;T. Takayanagi;J. Hasegawa
中科院分区：
文献类型：
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作者：
Kohei Saito;Yuya Watabe;T. Fujihara;T. Takayanagi;J. Hasegawa
利用密度泛函理论研究了O2与模型血红素络合物（由Fe（II）-卟啉和咪唑组成）结合的自旋反转机制.首先，我们应用最近提出的混合自旋哈密顿方法来定位不同总自旋多重性之间的自旋反转结构。九种自旋反转结构成功地优化了单重态-三重态、单重态-五重态、三重态-五重态和五重态-七重态自旋反转过程。我们发现，单重态-三重态自旋反转点位于短Fe-O距离的势能面区域周围，而单重态-五重态和五重态-七重态自旋反转点位于较长的Fe-O距离。这表明窄交叉和宽交叉模型在O2与Fe-卟啉络合物的结合中起作用。为了进一步理解自旋反转机制，我们进行了Born Oppenheimer分子动力学计算。还讨论了与不同自旋多重性之间的自旋反转动力学相关的反应坐标。
Spin‐inversion mechanisms in O2 binding to a model heme complex, consisting of Fe(II)‐porphyrin and imidazole, were investigated using density‐functional theory calculations. First, we applied the recently proposed mixed‐spin Hamiltonian method to locate spin‐inversion structures between different total spin multiplicities. Nine spin‐inversion structures were successfully optimized for the singlet–triplet, singlet–quintet, triplet–quintet, and quintet–septet spin‐inversion processes. We found that the singlet–triplet spin‐inversion points are located around the potential energy surface region at short Fe–O distances, whereas the singlet–quintet and quintet–septet spin‐inversion points are located at longer Fe–O distances. This suggests that both narrow and broad crossing models play roles in O2 binding to the Fe‐porphyrin complex. To further understand spin‐inversion mechanisms, we performed on‐the‐fly Born‐Oppenheimer molecular dynamics calculations. The reaction coordinates, which are correlated to the spin‐inversion dynamics between different spin multiplicities, are also discussed.