Adsorptive removal and catalytic performance of metal-organic frameworks containing mixed azolium-bipyridine ligand

Abstract

Two ligands, 1, 3-bis(4-carboxyphenyl)imidazolium chloride and 4, 4-bipyridine, were employed to prepare nickel and zinc azolium based MOFs, Ni-MOF and Zn-MOF by the mixed ligand solvothermal approach. The positively charged azolium moieties in the imidazolium linker resulted in a charged environment in the as-synthesized frameworks. As a result, Ni-MOF and Zn-MOF demonstrated preferential adsorption of CO2 over methane molecules in the gas phase adsorption due to the higher quadruple moment of CO2, which interacts more with the positively charged frameworks. Besides, in aqueous media, Ni-MOF and Zn-MOF exhibited incredible adsorption efficiency for anionic dyes. In the following, Ni-MOF was metallated at the carbene site of the azolium linker to generate the novel heterogeneous catalyst Pd/Ni-MOF, which was successfully applied for Sonogashira and Suzuki-Miyaura coupling reactions without losing its activity after three cycles.

Keywords

• Azolium MOFs
• Dye adsorption
• Post modification
• Cross-coupling reactions