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由分子内结相互作用促进的血--铜复合物的自旋互转
Andrew W Schaefer1, Melanie A Ehudin2, David A Quist2
1Department of Chemistry , Stanford University , Stanford , California 94305 , United States.
Journal of the American Chemical Society
|March 6, 2019
概括
具有结能力的合成桥复合物表现出可逆自旋交叉 (SCO). 分子内H键稳定低旋转状态,影响电子结构并使温度依赖的旋转状态相互转换.
科学领域:
- 生物有机化学
- 协调化学
- 光谱学
背景情况:
- 合成的过氧桥式血铜复合物是金属酶活性位点的关键模型.
- 了解这些复合体中的旋转状态转换是阐明生物机制的关键.
- 二次协调球相互作用,如结合,可以显著调节金属中心的特性.
研究的目的:
- 研究分子内键 (H键) 能力对过氧桥铜复合物的电子和几何结构的影响.
- 探索H结合对这些合成复合物的旋转状态及其旋转交叉 (SCO) 的潜力的影响.
- 阐明H键和溶剂相互作用稳定特定的自旋状态的机制.
主要方法:
- 含有H-结合功能的过氧桥式高旋转 (HS) 血铜 (L) 复合物的合成.
- 可变温度紫外线和2H核磁共振光谱检测温度依赖的自旋状态变化和溶剂结合.
- 共振拉曼 (rR) 光谱和密度功能理论 (DFT) 分析,以探测与H键和自旋状态相关的结构和电子变化.
主要成果:
- 与过氧核的分子内H结合相互作用有利于低旋转 (LS) 血铜 (L) 结构,诱导可逆旋转交叉 (SCO).
- 在低温下有利于LS状态,而H-结合会削弱O-O键,同时加强Fe-O键,与已知的LS复合物相比.
- 根据rR和DFT数据,H结合促进了核心几何变化,允许稳定LS状态的溶剂结合.
结论:
- 分子内H键是控制过氧桥接铜复合物的自旋状态的关键因素,使SCO成为可能.
- 该H键作为二次协调球的影响,调节电子和几何结构以稳定LS状态.
- 这些发现提供了对二次协调球体在金属酶中的作用和旋转状态控制机制的基本见解.
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