Jenks Tyler C, Bailey Matthew D, Hovey Jessica L, Fernando Shanilke, Basnayake Gihan, Cross Michael E, Li Wen, Allen Matthew J
Department of Chemistry , Wayne State University , 5101 Cass Avenue , Detroit , MI 48202 , USA . Email:
Chem Sci. 2017 Dec 21;9(5):1273-1278. doi: 10.1039/c7sc02479g. eCollection 2018 Feb 7.
We report the first catalytic use of a divalent lanthanide in visible-light-promoted bond-forming reactions. Our new precatalyst uses europium in the +2 oxidation state and is active in the presence of blue light from light-emitting diodes. The use of low-energy visible light reduces the occurrence of potential side reactions that might be induced by higher-energy UV light. The system described here uses zinc metal as a sacrificial reductant and is tolerant to wet, protic solvents. The catalyst can be made from relatively inexpensive and air-stable EuCl·6HO, and the ligand can be synthesized in large quantities in two steps. With 0.5% loading of precatalyst, an average of 120 turnovers was observed in six hours for reductive coupling of benzyl chloride. We expect that the results will initiate the study of visible-light-promoted photoredox catalysis using divalent europium in a variety of reactions.
我们报道了二价镧系元素在可见光促进的成键反应中的首次催化应用。我们的新型预催化剂使用处于 +2 氧化态的铕，并且在发光二极管发出的蓝光存在下具有活性。使用低能量可见光减少了可能由高能量紫外光引发的潜在副反应的发生。这里描述的体系使用锌金属作为牺牲还原剂，并且耐受潮湿的质子性溶剂。该催化剂可以由相对便宜且对空气稳定的 EuCl·6H₂O 制备，并且配体可以通过两步大量合成。在预催化剂负载量为 0.5% 时，对于苄基氯的还原偶联反应，在六小时内平均观察到 120 次周转。我们期望这些结果将引发在各种反应中使用二价铕进行可见光促进的光氧化还原催化研究。
