KAUST Catalysis Center (KCC), Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia.
KAUST Solar Center (KSC), Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia.
Nat Commun. 2022 May 18;13(1):2737. doi: 10.1038/s41467-022-30278-8.
Various methods that use a photocatalyst for electron transfer between an organic substrate and a transition metal catalyst have been established. While triplet sensitization of organic substrates via energy transfer from photocatalysts has been demonstrated, the sensitization of transition metal catalysts is still in its infancy. Here, we describe the selective alkylation of C(sp)-H bonds via triplet sensitization of nickel catalytic intermediates with a thorough elucidation of its reaction mechanism. Exergonic Dexter energy transfer from an iridium photosensitizer promotes the nickel catalyst to the triplet state, thus enabling C-H functionalization via the release of bromine radical. Computational studies and transient absorption experiments support that the reaction proceeds via the formation of triplet states of the organometallic nickel catalyst by energy transfer.
已经建立了各种使用光催化剂在有机底物和过渡金属催化剂之间进行电子转移的方法。虽然已经证明了通过光催化剂的能量转移来三重态敏化有机底物，但过渡金属催化剂的敏化仍处于起步阶段。在这里，我们描述了通过三重态敏化镍催化中间体来选择性地对 C(sp)-H 键进行烷基化，并彻底阐明了其反应机理。来自铱光敏剂的放热 Dexter 能量转移促进镍催化剂转变为三重态，从而通过释放溴自由基实现 C-H 官能化。计算研究和瞬态吸收实验支持反应通过能量转移形成有机金属镍催化剂的三重态来进行。
