Zr-Metal-Organic Frameworks Featuring TEMPO Radicals: Synergistic Effect between TEMPO and Hydrophilic Zr-Node Defects Boosting Aerobic Oxidation of Alcohols.

Metal-organic frameworks (MOFs) featuring multiple catalytic units are excellent platforms for heterogeneous catalysis. However, the synergism between multiple catalytic units for catalysis is far from being well understood. Herein, we reported the synthesis of a robust 2,2,6,6-tetramethylpiperidinyloxy (TEMPO) radical-functionalized Zr-MOF (UiO-68-TEMPO) in the form of single-crystalline and microsized crystals with varied missing linker defects. Detailed catalytic studies and theoretical calculations reveal that the synergistic effect between the TEMPO radicals and hydrophilic and defective Zr-nodes endows UiO-68-TEMPO with superior catalytic activity toward aerobic oxidation of alcohols. Our work not only offers a new route to design and synthesize highly effective MOF catalysts but also provides insights into the synergism between multiple catalytic sites.