Directed Electron Transfer

电子转移过程在化学反应、能量存储系统和现代信息传输设备中发挥着关键作用。这样的反应是由热力学驱动的，如果在几个伙伴之间进行选择，电子转移将产生一个热力学稳定的产物分布。选择性只能通过接近和还原电位获得。在这里，我们开始设计合理的方法来引导电子沿着一条特定的路径，当几个看似相同的路径可用。在这种情况下，选择性是通过选择激发波长获得的。主发色团的低能量激发导致电子向近端受体转移。更高的能量激发到相同的发色团导致能量转移到次级发色团，随后将电子转移到远端受体。氧化还原产物在自旋和/或化学性质方面有所不同。这个程序的最终成果是指围绕环的定向电子转移。因此，低能量激发导致顺时针方向的电子流，而高能量照明导致电子沿逆时针方向绕环运动。

Electron-transfer processes play key roles in chemical reactions, energy-storage systems and contemporary devices for information transfer. Such reactions are driven by thermodynamics and, given the choice between several partners, electron transfer will generate a thermodynamically stable distribution of products. Selectivity is acquired only by way of proximity and reduction potential. Here, we set out to devise rational ways to direct an electron along one particular pathway when several seemingly identical routes are available. In this case, selectivity is obtained by the choice of excitation wavelength. Low energy excitation of the main chromophore causes electron transfer to a proximal acceptor. Higher energy excitation into the same chromophore causes energy transfer to a secondary chromophore, which subsequently transfers an electron to a distal acceptor. The redox products differ in terms of spin and/or chemical identity. The ultimate achievement within this programme refers to directed electron transfer around a ring. Thus, low energy excitation causes clockwise electron flow but higher energy illumination causes electrons to move around the ring in an anti-clockwise direction.