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具有弱OH键的水溶性Fe (II) -H2O复合物通过可观测的单体Fe (III) -OH转移一个原子
Lisa M Brines1, Michael K Coggins, Penny Chaau Yan Poon
1Department of Chemistry, University of Washington , Campus Box 351700, Seattle, Washington 98195-1700, United States.
Journal of the American Chemical Society
|January 23, 2015
概括
这项研究详细介绍了金属离子特性如何影响O-H键裂变,这对于催化是至关重要的. 一个铁复合体 (Fe (II) -H2O) 显示出较弱的OH键,促进质子合电子转移 (PCET) 反应.
科学领域:
- 无机化学 无机化学
- 催化剂是一种催化剂.
- 反应机制 反应机制
背景情况:
- 水的氧化是能量转换的一个关键步骤,涉及具有挑战性的OH键裂变.
- 金属离子催化剂对于通过质子合电子转移 (PCET) 促进O-H键裂变至关重要.
- 调整金属离子电子结构和连接体环境对于催化剂设计至关重要.
研究的目的:
- 调查金属离子电子结构和连接体环境如何影响M(H2O) -H键裂变能量.
- 为了合成和表征一种能够经历PCET的Fe (II) -H2O复合物.
- 为了比较合成复合物的O-H键解离自由能量 (BDFE) 与相关的金属水离子.
主要方法:
- 一个Fe (II) -H2O复合物的合成和特征.
- 在水溶液中进行质子合电子转移 (PCET) 实验.
- 使用Pourbaix图表计算O-H债券BDFE.
- 使用TEMPO (2,2,6,6-tetramethylpiperidin-1-yl) 氧基的反应性研究.
主要成果:
- 一个新的Fe(II) -H2O复合物 (1) 被合成和表征.
- 复合物1接受PCET,形成一个罕见的单体Fe(III) -OH物种 (7).
- 复合体1的O-H BDFE计算为68.6 kcal/mol,明显低于H2O和[Fe ((II) ((H2O) 6)) ((2+).
- 综合体1向TEMPO捐赠了一颗原子,与抽象原子的相关M(n+) -OH综合体不同.
结论:
- 金属离子的电子结构和连接体环境显著调整了O-H键的能量.
- 合成的Fe (II) -H2O复合体表现出一个弱化的O-H键,促进了H原子的捐赠.
- 了解这些因素是设计有效的催化剂的关键,用于C-H激活和H2O氧化.
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