在Oligoproline中对质子合的氧化有浅距离依赖性
Brian Koronkiewicz1, John Swierk1, Kevin Regan1
1Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States.
Journal of the American Chemical Society
|June 9, 2020
概括
我们研究了距离如何影响生物模拟系统中的质子合电子转移 (PCET). 我们发现增加距离只会稍微降低电子传递率,与典型的电子传递过程不同.
科学领域:
- 仿生化学
- 生物物理化学
- 电子转移机制
背景情况:
- 生物电子转移 (ET) 通常涉及质子转移 (PT),形成协调的质子-电子转移 (CPET) 反应.
- 在生物ET路径中,CPET反应至关重要,经常涉及与ET合的远程PT.
- 了解ET在CPET中的距离依赖对于生物ET研究至关重要.
研究的目的:
- 在生物模拟质子合电子转移 (PCET) 系统中研究增加电子转移 (ET) 距离的动力效应.
- 探索ET在CPET反应中的独特距离依赖性,将其与标准ET对比.
- 评估CPET距离依赖对理解生物远程电荷转移的影响.
主要方法:
- 一系列金属的制备,其中氨酸供体和Ru (bpy) 32+受体由不同长度的寡烯桥连接在一起.
- 使用闪灭瞬时吸收技术测量分子内氨酸氧化速率常数.
- 作为捐赠者-接受者距离的函数的电子转移速率的动力分析.
主要成果:
- 氨酸氧化速率常数减少了125倍,增加了三种氨酸残留物,表明距离依赖程度较低.
- 与相关的分子内ET速率常数相比,这种距离依赖明显较小 (大小下降4-5级).
- 这种浅度依赖归因于需要更强的氧化剂,导致洞转移的有效道屏障高度较小.
结论:
- 该研究表明生物模拟CPET系统中电子传输的距离依赖性很小.
- 这一发现与纯电子ET系统中观察到的更的距离依赖性形成鲜明对比.
- 这些结果对理解生物系统中长距离的电荷传递机制有潜在的影响.
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