Temperature-Dependent Structures of Lanthanide Metal-Organic Frameworks Based on Furan-2,5-Dicarboxylate and Oxalate

Two series of lanthanide metal-organic frameworks, [Ln(FDA)(OX)(0.5)(H2O)(2)]center dot(H2O) (1Ln) (Ln = Pr 1, Nd 2, Eu 3, Gd 4, Tb 5), [Ln(FDA)(OX)(0.5)(H2O)(2)]center dot(H2O) (2Ln) (Ln = Sm 6, Tb 7, Dy 8, Ho 9, Yb 10) (OX = oxalate), have been prepared by reacting Ln(NO3)(3)center dot 6H(2)O with furan-2,5-dicarboxylic acid (H(2)FDA) at different temperatures under hydrothermal conditions. All the complexes are characterized by elemental analysis, IR, X-ray powder diffraction, and single-crystal X-ray diffraction. Structure analyses show that 1Ln and 2Ln are supramolecular isomerisms. 1Ln possesses a three-dimensional network with monoclinic space group P2(1)/c, whereas 2Ln exhibits a three-dimensional framework with monoclinic space group C2/c. The distinct architectures of these two series of ten complexes indicated that the reaction temperature plays an important role in the formation of such coordination structures. Meanwhile, the photoluminescent properties of 4, 5, 7, and 8 are also investigated in the solid state at room temperature.