Simple Transformation of Hierarchical Hollow Structures by Reduction of Metal-Organic Frameworks and Their Catalytic Activity in the Oxidation of Benzyl Alcohol.

Metal-organic framework (MOF)-based derivatives have been found to be promising heterogeneous catalysts for organic transformations. Herein, hollow-structure Cu-MOFs derived by reduction of Cu3 (BTC)2 (BTC=1,3,5-benzenetricarboxylate; denoted as RCB) were prepared by using hydrazine hydrate as a reducing agent under various conditions. The influence of hydrazine hydrate induced the structure of Cu3 (BTC)2 and led to dynamic variation in the interior and exterior as well as oxidation states of the Cu ion. The synthesized materials were characterized by SEM, TEM, N2 sorption isotherms, XRD, and XPS. The product of the catalytic reaction was observed by GC-MS. In addition, the prepared RCBs were found to have excellent catalytic activity and selectivity for benzyl alcohol oxidation when assisted by 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO).