Modulation of 1D Ru-Porphyrin Biomimetic COF to Enhance Synergistic Dual C─H Bond Air Oxidation for Cyclohexenone Synthesis.

Covalent organic frameworks (COFs) with tunable structures and high stability hold great potential in catalysis. However, traditional non-metallic COFs lack metal active sites, which limits catalytic efficiency. As the core structure of terminal oxygenases, metalloporphyrins can convert molecular oxygen into reactive oxygen species. The integration of metalloporphyrin units into COFs has been widely applied in various catalytic oxidation reactions. In contrast, 1D COFs possess more edge sites and efficient mass transfer capabilities, making them ideal catalytic platforms. We therefore constructed a 1D Ru-porphyrin-based COF (Ru-COF-Pcbb) with dispersed Ru sites, tunable pores, and high stability. Using air as the oxidant, Ru-COF-Pcbb achieves 95% cyclohexene conversion and 96% selectivity for α,β-unsaturated ketones under relatively mild conditions. Moreover, it maintains structural stability after multiple catalytic cycles and shows good activity towards various olefins. In situ characterizations and density functional theory (DFT) calculations indicate that the synergistic activation of cyclohexene and adamantane (AT) promotes the activation of molecular oxygen to generate peroxy radicals. Simultaneously, high-valent Ru oxo species (Ru = O) further regulate the transfer of oxygen species, thereby achieving selective oxidation. The synergistic catalytic oxidation system constructed in this study provides a technical reference for the selective activation of C-H bonds to prepare ketone compounds.