Facile synthesis of ultrathin metal-organic framework nanosheets for Lewis acid catalysis

摘要

Ultrathin metal-organic framework (MOF) nanosheets are attracting great interest in catalysis due to their unique and intriguing two-dimensional (2D) features.Although many progresses have been achieved,it is still highly desirable to develop novel strategies for controllable synthesis of the well-defined ultrathin MOF nanosheets.Herein we report a polyvinylpyrrolidone (PVP)-assisted route to synthesize the ultrathin Ni-MOF nanosheets characteristic of 1.5 nm in thickness,in which PVP is reacted with 2-aminoterephthalic acid (H2BDC-NH2) via formation of C=N bond,followed by coordination with Ni2+ ions to form the ultrathin MOF nanosheets.Impressively,when used in the Knoevenagel condensation reactions of propane dinitrile with different aldehydes,ultrathin Ni-MOF nanosheets display the significantly enhanced catalytic activity and good stability in respect with the bulk Ni-MOF,mainly owing to the exposed active sites as well as facile mass transfer and diffusion of substrates and products.