Jhun Byung Hak, Jang Jihoon, Lee Shinae, Cho Eun Jin, You Youngmin
Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul, 03722, Republic of Korea.
Department of Chemistry, Chung-Ang University, Seoul, 06974, Republic of Korea.
Nat Commun. 2024 Aug 3;15(1):6586. doi: 10.1038/s41467-024-50979-6.
Photocatalysis provides a versatile approach to redox activation of various organic substrates for synthetic applications. To broaden the scope of photoredox catalysis, developing catalysts with strong oxidizing or reducing power in the excited state is imperative. Catalysts that feature highly cathodic oxidation potentials and long lifetimes in their excited states are particularly in demand. In this research, we demonstrate the catalytic utility of two-coordinate Au(I) complex photocatalysts that exhibit an exclusive ligand-to-ligand charge-transfer (LLCT) transition in C-C cross-coupling reactions between N-heterocycles and (hetero)aryl halides, including redox-resistant (hetero)aryl chlorides. Our photocatalysis system can steer reactions under visible-light irradiation at a catalyst loading as low as 0.1 mol% and exhibits a broad substrate scope with high chemo- and regioselectivity. Our mechanistic investigations provide direct spectroscopic evidence for each step in the catalysis cycle and demonstrate that the LLCT-active Au(I) complex catalysts offer several benefits, including strong visible-light absorption, a 210 ns-long excited-state lifetime without short-lived components, and a 91% yield in the production of free-radical intermediates. Given the wide structural versatility of the proposed catalysts, we envision that our research will provide useful insights into the future utilization of the LLCT-active Au(I) complex for organic transformations.
光催化为各种有机底物的氧化还原活化提供了一种通用方法，可用于合成应用。为了拓宽光氧化还原催化的范围，开发在激发态具有强氧化或还原能力的催化剂势在必行。特别需要具有高阴极氧化电位和长激发态寿命的催化剂。在本研究中，我们展示了双配位Au(I)配合物光催化剂在N-杂环与（杂）芳基卤化物之间的C-C交叉偶联反应中的催化效用，这些反应包括抗还原（杂）芳基氯化物，该光催化剂表现出独特的配体到配体电荷转移（LLCT）跃迁。我们的光催化系统可以在低至0.1 mol%的催化剂负载量下，在可见光照射下引导反应，并表现出广泛的底物范围，具有高化学选择性和区域选择性。我们的机理研究为催化循环中的每一步提供了直接的光谱证据，并证明LLCT活性Au(I)配合物催化剂具有多种优势，包括强烈的可见光吸收、210 ns长的无短寿命成分的激发态寿命，以及自由基中间体生成的91%产率。鉴于所提出的催化剂具有广泛的结构多样性，我们设想我们的研究将为未来LLCT活性Au(I)配合物在有机转化中的应用提供有用的见解。
