Microporous Lanthanide Metal-Organic Frameworks Containing Coordinatively Linked Interpenetration: Syntheses, Gas Adsorption Studies, Thermal Stability Analysis, and Photoluminescence Investigation

Under solvothermal conditions, the reactions of trigonal-planar ligand, TATB (4,4',4 ''-s-triazine-2,4,6-triyl-tribenzoate) with Dy(NO3)(3), Er(NO3)(3), Y(NO3)(3), Yb(NO3)(3), gave rise to four microporous lanthanide metal-organic frameworks (MOFs), designated as PCN-17 (Dy), PCN-17 (Er), PCN-17 (Y), and PCN-17 (Yb), respectively. The four porous MOFs are isostructural, with their crystal unit parameters shrinking in the order of PCN-17 (Dy), PCN-17 (Y), PCN-17 (Er), and PCN-17 (Yb), which also reflects the lanthanides' contraction trend. All of them adopt the novel square-planar Ln(4)(mu(4)-H2O) cluster as the secondary building unit and contain coordinatively linked doubly interpenetrated (8,3)-connected nets. In addition to exhibiting interesting photoluminescence phenomena, the coordinatively linked interpenetration restricts the pore sizes and affords them selective adsorption of H-2 and O-2 over N-2 and CO, as well as renders them with high thermal stability of 500-550 degrees C as demonstrated from TGA profiles.