通过与p-oligophenylene结合的供体-桥梁-受体分子的自旋选择性电荷传输路径
Amy M Scott1, Tomoaki Miura, Annie Butler Ricks
1Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, USA.
Journal of the American Chemical Society
|November 13, 2009
概括
研究人员研究了捐赠者-桥梁-受体分子中的电荷转移,发现超级交换主导电子转移通路. 该研究量化了取决于距离的电子重组和旋转动态.
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-桥梁-接受者 (D-B-A) 系统对于理解电荷传输过程至关重要.
- 桥梁单元对电子转移动态和旋转连贯性的影响具有重大意义.
- 研究取决于距离的电荷分离和重组是设计分子电子设备的关键.
研究的目的:
- 合成和描述一系列具有不同p-oligophenylene桥梁长度的D-B-A三合体.
- 研究这些三元体中的电荷转移特性,包括电荷分离 (CS) 和电荷再组合 (CR).
- 用先进的光谱技术阐明电子转移和自旋动态的基本机制.
主要方法:
- 合成D-B-A三合体与3,5-二甲基-4-(9-甲基) 朱洛利丁 (DMJ-An) 供体和纳夫他林-1,8:4,5-bis(二氧化) (NI) 接受体,通过p-基烯 (Ph(n)) 桥梁 (n=1-5) 连接.
- 暂时吸收光谱学用于监测光诱导的电子转移和激素离子对形成.
- 磁场效应 (MFEs) 和时间分辨率电子偏磁共振 (TREPR) 光谱检测旋转动力学和电子合.
主要成果:
- 光刺激量化产生了一个自旋相干的基离子对,DMJ(+*) -An-Ph(n) -NI(-*).
- 两种CS和CR反应都显示了指数距离依赖,具有相似的缓冲系数 (β ≈ 0.35 Å−1).
- 超级交换被确定为单元和三元电荷重组路径的主导机制,具有明显的距离依赖 (单元β = 0.48 Å−1,三元β = 0.35 Å−1).
结论:
- 这些D-B-A三合体中的电荷传输机制是由超交换控制的,没有过渡到跳转.
- 旋转-旋转交换相互作用 (2J) 表现出一个指数距离依赖 (α = 0.36 Å−1),与三重CR相一致.
- 了解这些取决于距离的电子合和旋转动态对于设计高效的分子电荷传输系统至关重要.
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