线性自由能量关系和CO2的过渡状态分析
Kaeden Teindl1, Brian O Patrick1, Eva M Nichols1
1Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada.
Journal of the American Chemical Society
|July 27, 2023
概括
分子催化剂中的蛋白质组通过中继质子来加速二氧化碳的减少. 它们的酸度与外源酸一起决定了反应速度,指导了催化剂的设计.
科学领域:
- 电化学
- 催化剂
- 物理化学
背景情况:
- 分子催化剂利用二次协调球 (SCS) 基团和外源酸来减少二氧化碳中的质子转移.
- SCS与外源性酸酸度之间的相互作用及其对催化动力学的影响尚不完全理解.
研究的目的:
- 研究SCS和外源酸的酸度如何影响电化学CO2减排的动力学.
- 阐明来自SCS和外源酸的质子转移驱动力的机械贡献.
主要方法:
- 具有可调节的SCS胺基pKa值的铁四甲电催化剂的合成.
- 使用具有不同酸度的作为外源酸.
- 使用线性自由能量关系和艾灵分析来研究反应动力学.
主要成果:
- 具有较高酸性外源酸的催化动力学显示对SCS酸度的敏感性增加 (Brønsted α: 0.820.13).
- 动力学也变得对外源性酸性更敏感,而SCS酸性增加 (Brønsted α:0.620.32).
- 艾灵的分析表明,SCS酸度下降的过渡状态更加有序,这表明电荷和溶解的调制.
结论:
- 在限制速率的过渡状态下,SCS酸度在调节电荷积累和溶解方面发挥着至关重要的作用.
- 优化激活障碍需要考虑SCS和外源酸的pKa.
- 通过考虑所有质子继电器参与者,这些发现指导了电催化系统的合理设计.
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