The mechanistic understanding of catalytic radical reactions currently lags behind the flourishing development of new types of catalytic activation. Herein, an innovative single electron transfer (SET) model has been expanded by using the nonadiabatic crossing integrated with the rate-determining step of 1,5-hydrogen atom transfer (HAT) reaction to provide the control mechanism of radical decay dynamics through calculating excited-state relaxation paths of a paradigm example of the amide-directed distal sp³ C–H bond alkylation mediated by Ir-complex-based photocatalysts. The stability of carbon radical intermediates, the functional hindrance associated with the back SET, and the energy inversion between the reactive triplet and closed-shell ground states were verified to be key factors in improving catalytic efficiency via blocking radical inhibition. The expanded SET model associated with the dynamic behaviors and kinetic data could guide the design and manipulation of visible-light-driven inert bond activation by the utilization of photocatalysts bearing more or less electron-withdrawing groups and the comprehensive considerations of kinetic solvent effects and electron-withdrawing effects of substrates.

中文翻译：

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与功能位阻相关的扩展 SET 模型主导了酰胺导向的远端 sp3 C-H 功能化

目前对催化自由基反应的机理理解落后于新型催化活化的蓬勃发展。在此，通过将非绝热交叉与 1,5-氢原子转移 (HAT) 反应的速率决定步骤相结合，扩展了一种创新的单电子转移 (SET) 模型，通过计算激发态来提供自由基衰变动力学的控制机制。酰胺定向远端 sp ³范例的状态弛豫路径由基于 Ir 配合物的光催化剂介导的 C-H 键烷基化。碳自由基中间体的稳定性、与背 SET 相关的功能位阻以及反应性三重态和闭壳基态之间的能量反转被证实是通过阻断自由基抑制来提高催化效率的关键因素。与动力学行为和动力学数据相关的扩展 SET 模型可以通过使用带有或多或少的吸电子基团的光催化剂以及对动力学溶剂效应和电子的综合考虑来指导可见光驱动的惰性键活化的设计和操作- 基材的退缩效应。