MOFs with 12-coordinate 5f-block metal centers

We have constructed an unprecedented MOF platform that accommodates a range of 5f-block metal ions (Th⁴⁺, U⁴⁺, Np⁴⁺, Pu⁴⁺) as the primary building block. The isoreticular actinide metal-organic frameworks (An-MOFs) exhibit periodic trends in the 12-coordinate metal environment, ligand configuration, and resulting ultramicroporosity. It holds potential in distinguishing neighboring tetravalent actinides. The metal ionic radius, carboxylate bite angle, anthracene plane twisting, inter-ligand interac-tions, and countercation templating collectively determine an interplay between solvation, modulation, and complexation, re-sulting in a coordination saturation of the central actinide while lanthanide counterparts are stabilized by the formation of a dimer-based motif. Quantum chemical calculations indicate that this large coordination number is only feasible in the high-symmetry environment provided by the An-MOFs. This category of MOFs not only demonstrates autoluminescence (4.16 ×10⁴ counts per second per gram) but also portends a wide-bandgap (2.84 eV) semiconducting property with implications for a multitude of applications such as hard radiation detection.