Post-synthesis functionalization of MIL-101 using diethylenetriamine: a study on adsorption and catalysis

Abstract

An effective metal organic framework (MOF) catalyst (DETA-MIL-101) was prepared by grafting an electron-rich triamine functional group to the open metal sites in MIL-101. The samples were characterized via XRD, FT-IR, and N₂ adsorption-desorption measurements, and their N content was measured using EA. The CO₂ and H₂O adsorption-desorption properties were measured and compared with those of non-functionalized MIL-101. Their catalytic performances in the Knoevenagel condensation between benzaldehyde and malononitrile were examined, and the catalyst stabilities were confirmed using recycling and hot filtering experiments. Finally, the Pd²⁺ ions (0.5, 1.0, and 3.0 wt%) were immobilized onto the amine species that were grafted to the MIL-101 using PdCl₂ and were tested for Heck reactions of the acrylic acid and iodobenzene in N,N-dimethylacetamide as a solvent with triethylamine additives as a function of time. The catalyst stability was re-established via recycling and hot filtering experiments.