在多Ru替代聚氧甲酸盐上的二氧化物和水激活过程:与"蓝色二次体"水氧化催化剂的比较
Aleksey E Kuznetsov1, Yurii V Geletii, Craig L Hill
1Cherry L. Emerson Center for Scientific Computation and Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, USA.
Journal of the American Chemical Society
|April 25, 2009
概括
氧气和水的激活在多替代的多氧化物中进行了研究. 对O2激活的关联途径在动力学上受到青,形成Ru(IV) = O单位并防止水的氧化.
科学领域:
- 无机化学 无机化学 有机化学
- 计算化学计算化学
- 材料科学 材料科学 材料科学
背景情况:
- 聚氧甲酸盐 (POMs) 是具有可调节电子特性的多功能无机集群.
- 替代POM对催化应用有兴趣,包括氧化反应.
- 了解二氧化碳和水激活的机制对于开发高效的催化剂至关重要.
研究的目的:
- 为了研究多替代多氧化状态上的二氧化和水激活机制.
- 确定O2激活的首选反应途径 (逐步或协调).
- 将Ru-POM复合物的反应性与其他已知的氧化催化剂进行比较.
主要方法:
- 使用B3LYP方法进行密度函数理论 (DFT) 计算.
- 对反应路径,能量障碍和热力学配置文件的分析.
- 进行了气相和水溶解的计算.
主要成果:
- 氧2与Ru2替代的玛-凯金多氧化态的反应是一种高度外热的4电子过程.
- 对O2激活的协同 (关联) 途径在动力学上比步骤 (分离) 途径更有利.
- 反应通过几个中间体进行,最终形成Ru(IV) = O单位,反向反应 (水氧化) 是高度内热的.
结论:
- 研究的Ru2-POM复合物表现出高稳定性,不太可能催化水氧化.
- [SiW10O36](4-) 连接体的电子丰富性质有助于Ru-POM复合物的稳定性,与蓝色二次体类似物相比.
- 这些发现为在氧化催化过程中多POMs的活性提供了洞察力.
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