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 (H 2 O) 2 ]·(H 2 O) ( 1Ln ) (Ln = Pr 1, Nd 2, Eu 3, Gd 4, Tb 5 ), [Ln(FDA)(OX) 0.5 (H 2 O) 2 ]·(H 2 O) ( 2Ln ) (Ln = Sm 6, Tb 7, Dy 8, Ho 9, Yb 10 ) (OX = oxalate), have been prepared by reacting Ln(NO 3 ) 3 ·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 P 2 1 / c, whereas 2Ln exhibits a three-dimensional framework with monoclinic space group C 2/ 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.