在多甲酸框架内稳定的Mn (IV) 和Mn (V) -Hydroxo物种的活性和O2形成
Roy E Schreiber1, Hagai Cohen2, Gregory Leitus2
1†Department of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel.
Journal of the American Chemical Society
|June 13, 2015
概括
聚甲酸中-氧集群在电子转移中表现出反应性,但氧原子捐赠较差. 聚合Mn(IV) -OH-PFOM与特定的离子加速O2的形成,这表明水氧化的一种四分子中间体.
科学领域:
- 无机化学 无机化学
- 催化剂是一种催化剂.
- 材料科学 材料科学 材料科学
背景情况:
- -oxo和氧复合物是氧化和水氧化的关键,经常模仿酶.
- 酶模仿物可以在恶劣的条件下分解,这激励了对稳定的无机氧化物集群的研究.
- 了解氧化物环境中的反应性中间体对于实际应用至关重要.
研究的目的:
- 合成和描述具有各种氧化状态 (II-V) 的替代多甲酸盐 (PFOM).
- 研究这些-PFOM化合物的反应性,特别是它们的氧原子捐赠和电子转移能力.
- 探索酸盐对Mn(IV) - 氧-PFOM氧化演变的聚合和反应性的影响.
主要方法:
- 一系列替代PFOMs的合成.
- 使用磁性易感性,X射线光电子光谱学 (XPS),X射线吸收近边缘结构 (XANES),扩展X射线吸收细结构 (EXAFS),电子显微镜和DOSY NMR进行表征.
- 在水中的反应性研究,包括氧原子转移和电子转移氧化,使用不同的酸盐添加剂.
主要成果:
- 隔离Mn{II,III,IV,V) -PFOM化合物,具有已确认的氧化状态和配体环境 (水或).
- (IV) -OH-PFOM和 (V) -OH-PFOM是较差的氧原子捐赠体,但在电子转移氧化中有效.
- 由Cs+,Rb+,K+ (但不是Li+,Na+) 诱导的Mn(IV) -OH-PFOM的聚合加速了O2的形成,支持了四分子中间机制.
结论:
- -PFOMs为研究氧化状态和氧化环境中的反应性提供了一个稳定的平台.
- 观察到的聚合行为突出显示了在催化活动中由阴离子诱导的结构变化的作用.
- 一种四分子Mn(IV) - 氧介质被提议作为一种可行的途径,用于氧化基系统中的O2形成.
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