Synthesis, structure and adsorption properties of lanthanide–organic frameworks with pyridine-3,5-bis(phenyl-4-carboxylate)

Abstract

Under solvothermal conditions, reactions of pyridine-3,5-bis(phenyl-4-carboxylic acid) (H₂L) with lanthanide metal salts give rise to three new metal–organic frameworks (MOFs) with the formula {[Ln₄(L)₃(μ₃-OH)₄(H₂O)₄]·(NO₃)₂·solvent}_n [Ln = Er (1), Yb (2) and Lu (3)]. The complexes were characterized by single crystal and powder X-ray diffraction, IR and thermogravimetric analyses. They have the same two-fold interpenetrating three-dimensional (3D) framework structures with [Ln₄(COO)₆(μ₃-OH)₄(H₂O)₄] clusters as secondary building units (SBUs) and a rare 6-connected lcy topology with the point (Schläfli) symbol of {3³·5⁹·6³}. Interestingly, 1–3 show selective and hysteretic sorption of CO₂ over N₂, and the photoluminescence properties of the complexes were also investigated.