A new strongly paramagnetic cerium-containing microporous MOF for CO₂ fixation under ambient conditions

Abstract

Metal organic frameworks (MOFs) bearing multicarboxylate linkers are in great demand for designing robust heterogeneous catalysts. A new microporous Ce(iii)-based metal organic framework (Ce₂NDC₃) has been synthesized under solvothermal conditions, which showed strong paramagnetism and a CO₂ uptake capacity of 1.64 mmol g^-1 (7.23 weight%) at 273 K. The Ce₂NDC₃ showed high catalytic activity in CO₂ fixation for the synthesis of cyclic carbonates with a maximum yield of 92% at ambient temperature and pressure. This rare earth metal-based MOF has been well characterized by single crystal X-ray diffraction, PXRD, N₂ adsorption/desorption, UHR-TEM, FESEM, FTIR, ¹³C MAS NMR and TGA. Here, we have carried out magnetic analysis, which revealed that the Ce(iii) in this MOF exhibited ²F_5/2 magnetism in the ground state. The Ce₂NDC₃ catalyst showed high recycling efficiency in CO₂ fixation reactions, together with retention of the MOF structure after several rounds of reuse. Presumably, the presence of acidic Ce(iii) metal ions and microporosity in the coordinated polymer network is responsible for the high catalytic activity.