在捐赠-桥梁-接受分子中,通过电线状桥梁进行长距离电子传输的 conformational gating
W B Davis1, M A Ratner, M R Wasielewski
1Department of Chemistry and Center for Nanofabrication and Molecular Self-Assembly, Northwestern University, Evanston, Illinois 60208-3113, USA.
Journal of the American Chemical Society
|August 9, 2001
概括
分子动力学,特别是基基基桥内的扭动运动,极大地影响了捐赠-桥梁-接受分子中的电子转移速率. 这些动态,而不是标准理论,门电荷分离和重组,影响分子电线设计.
科学领域:
- 光化学和光物理学
- 分子电子学分子电子学
- 有机化学 有机化学
背景情况:
- 捐赠者-桥接收者 (DBA) 分子通过超交换或跳跃机制促进电子转移 (ET).
- 奥利戈-p-乙烯 (OPV) 桥梁可以在ET过程中充当分子线.
- 标准ET理论通常依赖于Condon近似,这可能无法完全捕捉复杂的分子动力学.
研究的目的:
- 为了研究桥梁动力学对电子转移 (ET) 的关键影响,在一系列的五个DBA分子中.
- 为了确定温度依赖的动态如何影响电荷分离 (CS) 和电荷再组合 (CR) 速率.
- 了解扭转运动在远距离ET和分子电线行为中的作用.
主要方法:
- 合成五个具有不同OPV桥梁长度的DBA分子 (四素捐赠者,甲胺接受者).
- 对电荷分离 (CS) 和电荷再组合 (CR) 速率的温度依赖性研究.
- 激活能量的分析和与已知的振动模式进行比较,以探测分子运动.
主要成果:
- CS速率与标准ET理论有所不同,表明在捐赠体和桥梁之间通过扭动运动形成门.
- 对CS的激活能量在分子之间是相似的,与特定的振动模式相关联.
- 观察到CS和CR速率的复杂温度依赖性,特别是对于较长的桥梁,由于扭转运动.
- 在较短的桥梁中观察到的不同扭转运动之间的竞争,导致不同的温度依赖.
结论:
- 结合桥内的低频扭矩运动关键地控制了长距离ET和分子线功能.
- 标准的ET理论不足以描述受这些特定分子动力学影响的ET.
- 未来使用联桥的分子装置设计必须考虑这些扭矩动力学.
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