A versatile synthetic strategy towards rare earth based metal-organic frameworks

Rare earth metal-organic frameworks (RE-MOFs) have drawn wide attention owing to diverse network structures and various application prospects. However, due to the unpredictable formation of the nodes, it is still challenging to design novel RE-MOFs. A novel versatile strategy was developed employing a RE-acetate complex (RE₂(CH₃COO)₆·4H₂O) as a precursor to construct RE-MOFs. 2D RE-MOFs (RE-DBP) and 3D RE-MOFs (RE-TCPP) could be obtained by using dicarboxylic porphyrin ligands H₂DBP and tetracarboxylic porphyrin ligands H₂TCPP, respectively. Ten RE-MOFs were further synthesized to verify the universality of the methodology. Highly crystalline RE-MOFs could also be prepared at room temperature via the developed strategy, which could significantly promote large-scale preparation and practical application of RE-MOFs. As proof of the concept, the performance of porphyrin-based RE-MOFs was investigated in the photocatalytic cycloaddition of CO₂ with epoxides. Among the RE-DBP(Co) MOFs, Tb-DBP(Co) exhibited the best photocatalytic performance, which was also greater than that of the corresponding 3D MOF Tb-TCPP(Co) due to the optimal 2D structure and thus the accelerated photogenerated charge separation and transfer process. This work not only provides a novel versatile strategy to design and develop RE-MOFs, but also proposes a promising approach for the potential bulk production of RE-MOFs at room temperature.