The highly selective oxidation of aromatic amines into azoxyarenes holds significant value in the synthesis of fine chemicals, dyes, and pharmaceuticals. However, achieving high efficiency and selectivity for this transformation remains a major challenge in the field of catalysis due to the complex reaction pathways and the tendency to form undesired byproducts.

Recently, a research team led by Prof. LI Guodong from the National Center for Nanoscience and Technology (NCNST) published a breakthrough study in Advanced Materials. The team proposed an innovative catalyst design strategy utilizing a metal-organic framework (MOF-808) to successfully develop a highly efficient dual-site synergistic catalytic system, effectively overcoming the selectivity challenges in aromatic amine oxidation.

In this study, the researchers constructed spatially adjacent pairs of Lewis acidic zirconium (Zr) sites and terminal hydroxyls within the pores of the MOF. They discovered that this precisely designed "dual-site" structure can efficiently activate hydrogen peroxide (H₂O₂), a mild oxidant, through hydrogen-bonding interactions. This activation process generates a crucial non-radical Zr-OOH active species.

This unique non-radical pathway fundamentally alters the reaction kinetics. Experimental results demonstrated that this catalytic system exhibits outstanding activity and near-perfect selectivity in converting aniline into reaction intermediates and further coupling them into azoxybenzene. The system effectively suppresses the over-oxidation and side reactions commonly associated with traditional radical pathways.

This work not only solves a challenging problem in the selective oxidation of aromatic amines but also provides profound theoretical insights and broad application prospects for designing highly active, multi-site synergistic biomimetic catalysts using porous crystalline materials.