Department of Photochemistry and Molecular Science, Uppsala University, Box 523, 751 20 Uppsala, Sweden.
Chemistry. 2010 Mar 1;16(9):2830-42. doi: 10.1002/chem.200902716.
The first examples of rodlike donor-photosensitizer-acceptor arrays based on bis-2,6-di(quinolin-8-yl)pyridine Ru(II) complexes 1a and 3a for photoinduced electron transfer have been synthesized and investigated. The complexes are synthesized in a convergent manner and are isolated as linear, single isomers. Time-resolved absorption spectroscopy reveals long-lived, photoinduced charge-separated states (tau(CSS) (1a)=140 ns, tau(CSS) (3a)=200 ns) formed by stepwise electron transfer. The overall yields of charge separation (> or = 50% for complex 1a and > or = 95% for complex 3a) are unprecedented for bis-tridentate Ru(II) polypyridyl complexes. This is attributed to the long-lived excited state of the Ru(dqp)(2) complex combined with fast electron transfer from the donor moiety following the initial charge separation. The rodlike arrangement of donor and acceptor gives controlled, vectorial electron transfer, free from the complications of stereoisomeric diversity. Thus, such arrays provide an excellent system for the study of photoinduced electron transfer and, ultimately, the harvesting of solar energy.
首例基于双-2,6-二(8-喹啉基)吡啶钌(II)配合物 1a 和 3a 的棒状给体-敏化剂-受体的光诱导电子转移的阵列已被合成并进行了研究。这些配合物采用收敛方式合成，并分离为线性、单异构体。时间分辨吸收光谱揭示了由逐步电子转移形成的长寿命、光诱导电荷分离态(tau(CSS)(1a)=140 ns，tau(CSS)(3a)=200 ns)。电荷分离的总产率（对于配合物 1a 大于等于 50%，对于配合物 3a 大于等于 95%）对于双齿配位的 Ru(II)多吡啶配合物来说是前所未有的。这归因于 Ru(dqp)(2)配合物的长寿命激发态与初始电荷分离后供体部分的快速电子转移相结合。给体和受体的棒状排列提供了受控制的、有向的电子转移，避免了立体异构多样性的复杂性。因此，这样的阵列为光诱导电子转移的研究提供了一个极好的体系，并最终为太阳能的收集提供了可能。
