Probing the efficiency of electron transfer through porphyrin-based molecular wires.
Probing the efficiency of electron transfer through porphyrin-based molecular wires.
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DOI：
10.1021/ja067447d
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发表时间：
2007-03
影响因子：
15
通讯作者：
Mikael U. Winters;Emma Dahlstedt;Holly E Blades;Craig J. Wilson;M. J. Frampton;H. Anderson;B. Albinsson
中科院分区：
文献类型：
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作者：
Mikael U. Winters;Emma Dahlstedt;Holly E Blades;Craig J. Wilson;M. J. Frampton;H. Anderson;B. Albinsson
长距离电子转移对于分子电子学和太阳能收集领域的许多未来应用非常重要。在这些背景下，发现能够在纳米距离上以受控方式有效地介导电子的分子系统，即充当分子线的结构，是非常感兴趣的。在这里，我们研究了一系列的丁二烯连接的卟啉低聚物与二茂铁和富勒烯（C60）的终端分离的一个，两个，或四个卟啉单元（Pn，n = 1，2，或4）。当卟啉低聚物桥被光激发时，通过一系列电子转移步骤形成长程电荷分离态，并且使用时间分辨吸收和发射测量阐明了这些系统中的光诱导电荷分离和电荷复合的速率。通过这些共轭卟啉低聚物的长程电荷复合速率非常快（kCR 2 = 15 - 1.3 × 108 s-1），并且表现出非常弱的距离依赖性，特别是与n = 2和n = 4的系统相比。卟啉四聚体介导超过65 A的快速长程电荷转移的观察对于这些结构作为分子导线的应用是重要的。
Electron transfer over long distances is important for many future applications in molecular electronics and solar energy harvesting. In these contexts, it is of great interest to find molecular systems that are able to efficiently mediate electrons in a controlled manner over nanometer distances, that is, structures that function as molecular wires. Here we investigate a series of butadiyne-linked porphyrin oligomers with ferrocene and fullerene (C60) terminals separated by one, two, or four porphyrin units (Pn, n = 1, 2, or 4). When the porphyrin oligomer bridges are photoexcited, long-range charge separated states are formed through a series of electron-transfer steps and the rates of photoinduced charge separation and charge recombination in these systems were elucidated using time-resolved absorption and emission measurements. The rates of long-range charge recombination, through these conjugated porphyrin oligomers, are remarkably fast (kCR2 = 15 - 1.3 x 108 s-1) and exhibit very weak distance dependence, particularly comparing the systems with n = 2 and n = 4. The observation that the porphyrin tetramer mediates fast long-range charge transfer, over 65 A, is significant for the application of these structures as molecular wires.