Synthetic Model Approach to the Elucidation of Photosynthetic Electron Transfer

在光合作用的各种过程中，光致电子传递对光子能量的利用起着至关重要的作用。通过加速电子正向转移和延缓电子反向转移相结合，巧妙地控制了自然电子转移过程，实现了稳定的电荷分离。为了了解光合作用电子传递的控制因素，并将其应用于人工光合作用或分子电子学的构建，我们制备了各种模型化合物，从中提取特定的因子。基于这些化合物的光物理性质，我们得到了1)相互取向效应，2)插入pi系统的效应，3)氧化还原对之间配位键的效应，4)受体的大小和形状效应。为了利用电荷分离态，合成了末端带有SMe基团的C_<60>-连接卟啉，并利用S-Au键作为自组装单分子膜将其固定在金表面。当样品被照射时，观察到较大的光电流。

Among various processes of photosynthesis photoinduced electoron transfer plays a crucial role in the utilization of photon energy. The natural electron transfer process is quite skillfully controlled to achieve stable charge separation by the combination of the acceleration of forward electron transfer and the retardation of back electron transfer. In order to get information on the controlling factors of photosynthetic electron transfer and to apply the principle for the construction of artificial photosynthesis or molecular electronics, we have prepared various model compounds from which particular factors can be extracted. Based on the photophysical properties of these compounds we got results on 1) mutual orientation effect, 2) effect of inserted pi-system, 3) effect of coordination bond between a redox pair, 4) size and shape effect of an accepter. For the utilization of charge-separated state, C_<60>-linked porphyrin with a SMe group at the terminal position was synthesized and fixed it on gold surface using S-Au bond as self-assembled monolayr. When the sample was irradiated, large photocurrent was observed.