Institute of Organic Chemistry, University of Regensburg, D-93040 Regensburg, Germany.
Science. 2014 Nov 7;346(6210):725-8. doi: 10.1126/science.1258232.
Biological photosynthesis uses the energy of several visible light photons for the challenging oxidation of water, whereas chemical photocatalysis typically involves only single-photon excitation. Perylene bisimide is reduced by visible light photoinduced electron transfer (PET) to its stable and colored radical anion. We report here that subsequent excitation of the radical anion accumulates sufficient energy for the reduction of stable aryl chlorides giving aryl radicals, which were trapped by hydrogen atom donors or used in carbon-carbon bond formation. This consecutive PET (conPET) overcomes the current energetic limitation of visible light photoredox catalysis and allows the photocatalytic conversion of less reactive chemical bonds in organic synthesis.
生物光合作用利用数种可见光光子的能量来实现具有挑战性的水氧化，而化学光催化通常只涉及单光子激发。苝二酰亚胺通过可见光光诱导电子转移 (PET) 还原为其稳定的有色自由基阴离子。我们在此报告，随后激发该自由基阴离子会累积足够的能量，用于还原稳定的芳基氯，得到芳基自由基，后者可被氢原子供体捕获，或用于碳-碳键形成。这种连续的 PET（conPET）克服了可见光光氧化还原催化目前的能量限制，并允许在有机合成中转化反应性较低的化学键的光催化转化。
