Metal–Organic Frameworks with Tb₄ Clusters as Nodes: Luminescent Detection of Chromium(VI) and Chemical Fixation of CO₂

Two multifunctional metal–organic frameworks based on cubane-like tetrahedron Tb4 clusters as nodes have been synthesized and characterized. Compound 1 exhibits a 2D lanthanide–organic framework with Tb4 clusters as nodes, and compound 2 possesses a 3D framework with Tb4 clusters and Mn2+ as nodes. Interestingly, luminescent investigations on them reveal that the two compounds can act as recyclable luminescent probes for chromium­(VI) anion species and the corresponding detection limit can reach 10–7 mol/L. Furthermore, 1 and 2 own efficient catalytic activity for the chemical fixation of CO2 with epoxides under mild conditions. Importantly, they both can be recycled at least three times without compromising the activity.