VanNatta Peter E, Archambault Cynthia M, Wang Sicheng, Lyu Tengteng, D'Amelio Jack, Martell Noah J, Watson Scott K, Wang Kunyu, Liu Zhenxian, Kieber-Emmons Matthew T, Yan Hao
Department of Chemistry, University of North Texas, Denton, TX 76205, USA.
Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Sci Adv. 2024 Oct 4;10(40):eadq3366. doi: 10.1126/sciadv.adq3366.
Nonsymmetrical oxygen-bridged binuclear copper centers have been proposed and modeled as intermediates and transition states in several C─H oxidation pathways, leading to the postulation that structural dissymmetry enhances the reactivity of the bridging oxygen. However, experimentally characterizing the structure and reactivity of these transient species is remarkably challenging. Here, we report the high-pressure synthesis of a metastable nonsymmetrical dicopper-μ-oxo compound with exceptional reactivity toward the mono-oxygenation of aliphatic C─H bonds. The nonequivalent coordination environment of copper stabilizes localized mixed valency and greatly enhances the hydrogen atom abstraction activity of the bridging oxygen, enabling room-temperature hydroxylation of methane under pressure. These findings highlight the role of dissymmetry in the reactivity of binuclear copper centers and demonstrate precise control of molecular structures by mechanical means.
非对称氧桥联双核铜中心已被提出并被模拟为几种C─H氧化途径中的中间体和过渡态，这导致人们推测结构不对称会增强桥连氧的反应活性。然而，通过实验表征这些瞬态物种的结构和反应活性极具挑战性。在此，我们报告了一种亚稳非对称二铜-μ-氧代化合物的高压合成，该化合物对脂肪族C─H键的单加氧反应具有异常的反应活性。铜的不等价配位环境稳定了局部混合价态，并极大地增强了桥连氧的氢原子提取活性，从而能够在压力下实现甲烷的室温羟基化。这些发现突出了不对称性在双核铜中心反应活性中的作用，并展示了通过机械手段对分子结构的精确控制。
