对低旋转FeIV=O复合物的光谱和量子化学研究:Fe-O结合及其对反应性的贡献
Andrea Decker1, Jan-Uwe Rohde, Eric J Klinker
1Department of Chemistry, Stanford University, Stanford, California 94305, USA.
Journal of the American Chemical Society
|December 7, 2007
概括
高价值的铁氧物种在酶催化过程中至关重要. 它们的Fe-O键被使用光谱学研究,揭示了在原子抽象反应中具有更高反应性的强pi键相关性.
科学领域:
- 生物有机化学 生物有机化学
- 频谱学是一种光谱学.
- 计算化学的计算化学
背景情况:
- 高价值FeIV=O物种是单核非血铁酶催化中的关键中间体.
- 结构定义的FeIV=O模型复合体提供了对酶机制的洞察力.
- 了解Fe-O键对于阐明反应性至关重要.
研究的目的:
- 使用VT-MCD光谱学评估三个FeIV=O (S = 1) 模型复合物的电子结构和Fe-O键.
- 将Fe-O键强度和共价性与反应性的实验数据相关联,特别是在原子抽象中.
- 通过计算来研究涉及到反应的边界分子轨道 (FMO).
主要方法:
- 使用可变温度磁圆二元化 (VT-MCD) 光谱学研究了三个FeIV=O (S = 1) 模型复合体.
- 对MCD光谱的分析提供了有关Fe-O拉伸频率,键长和激发状态下的pi键贡献的信息.
- 密度函数计算被用来关联实验结果和探测FMO.
主要成果:
- 这三个FeIV=O模型复合体表现出强烈且共价的Fe-O pi键.
- 具有最高反应性的FeIV=O (S = 1) 复合体 ([FeIV(O) ((N4Py) ]2+) 具有最强的Fe-O pi 键.
- 实验和计算数据揭示了FMO,特别是未被占用的β-旋转d(xz/yz) 轨道在激活电友攻击中的作用.
- 生物相关的FeIV=O (S = 2) 中间体利用类似的pi-FMO通路和额外的sigma-FMO通路.
结论:
- Fe-O pi 键的强度和共价性直接影响FeIV=O 种的反应性.
- 在模型复合体和酶中间体中,pi-FMO通路对于电友性攻击至关重要.
- 这项研究提供了对Fe-O键及其在高价值铁氧物种反应中的作用的详细实验和计算理解.
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