Amine Grafting on Coordinatively Unsaturated Metal Centers of MOFs: Consequences for Catalysis and Metal Encapsulation
The coordinatively unsaturated sites in MIL-101, Cr3(F,OH)(H2O)2O[(O2C)-C6H4-(CO2)]3⋅n H2O (n≈25), having zeotypic giant pores can be selectively functionalized in a way differing from that of mesoporous silica. Metal–organic frameworks, grafted with ethylenediamine or diethylenetriamine on the unsaturated CrIII sites of MIL-101, exhibit remarkably high activities in the Knoevenagel condensation relative to that of the mesophase.