Porous Lanthanide-Organic Frameworks: Control over Interpenetration, Gas Adsorption, and Catalyst Properties

Two isomorphous lanthanide-organic frameworks, Ln(BDC)(1.5)(DMF)-(H2O) (Ln = Er (1), Tm (2)) have been synthesized based on 1,4-benzenedicarboxylic acid (H2BDC). Because of the 2-fold interpenetration, the pores are partly blocked and there are no significant gas adsorptions for these two interpenetrating nets. Through control over interpenetration by applying an organic ligand with hindrance groups or replacing coordinated solvent molecules with a chelating ligand, three non-interpenetrating lanthanide-organic frameworks, Er-2(BDC)(3)(phen)(2)center dot 3H(2)O (3), Tm-(TBDC)(1.5)(DMF)(H2O)center dot 2H(2)O (4), Er-2(TBDC)(3)(phen)(2)center dot 4DMF center dot 2H(2)O (5), possessing the same topology with 1 and 2, have been synthesized and characterized. Further changing reaction conditions, three other porous lanthanide-organic frameworks with different structures with 1-5, Tm(BDC)(1.5)(H2O)center dot 0.5DMF center dot C2H5OH center dot 2H(2)O (6), Tm-4(BDC)(6)(H2O)(2)(DMF)(C2H5OH)center dot 2DMF center dot 2H(2)O (7), and Sm(TBDC)(1.5)(phen)-(H2O)center dot DMF center dot H2O (8), have been constructed. Gas sorption measurements for 5, 6, 7, and 8 have been carried out and revealed that these materials possess permanent porosity. The catalytic property for complex 6 has also been studied.