对二铁 (VI) 介质在水中的酸盐依赖氧气演变中的研究
Rupam Sarma1, Alfredo M Angeles-Boza, David W Brinkley
1Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA.
Journal of the American Chemical Society
|August 21, 2012
概括
酸盐 (K(2) FeO(4)) 通过分子内氧联合机制从水中产生氧气. 这项研究通过动态同位素效应和计算分析证实了O-O键的形成.
科学领域:
- 无机化学 无机化学
- 化学动力学 化学动力学
- 计算化学计算化学
背景情况:
- 酸盐 (K2FeO4) 是一种氧化剂,能够从酸性溶液中的水中产生分子氧气.
- 了解O-O键形成的机制对于控制氧进化反应至关重要.
研究的目的:
- 阐明在酸性溶液中酸盐反应期间O-O键形成的机制.
- 调查过渡状态,特别是水攻击 (WA) 和氧联合 (OC) 在氧进化过程中的作用.
主要方法:
- 在不同酸度下利用了H(2) O和D(2) O的停止流动力学.
- 分析了竞争性氧-18动态同位素对水消耗的影响.
- 运用密度函数理论 (DFT) 来评估单体和二元酸盐的WA和OC过渡状态.
- 为预测同位素结构计算的振动频率 (18) O KIEs.
主要成果:
- 使用竞争性同位素分离方法确定了实验性 (18) O KIE.
- 对于不同的过渡状态模型,DFT计算预测了18O KIEs.
- 在实验和理论 (18) O KIEs之间观察到很高的一致性.
- 这些结果强烈支持了分子内氧联合 (OC) 机制.
结论:
- 在酸铁酸盐与水的反应中,O-O键的形成是通过一个涉及二铁 (VI) 中介的分子内部OC机制进行的.
- 由于计算的高自由能障碍和与实验同位素效应的分歧,排除了诸如水攻击 (WA) 等替代机制.
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