Two Series of Lanthanide Metal‐Organic Frameworks Constructed from Crown‐Ether‐Like Secondary Building Units

Two series of lanthanide metal‐organic frameworks, [KLn 3 (FDCA) 5 (H 2 O) 5 ] · solvent ( 1Ln ) (Ln = La 1 , Ce 2 , Pr 3 ), [K 4 Ln 8 (FDCA) 14 (H 2 O) 30 ] · 2(H 2 FDCA) · DMAC · 10(H 2 O) ( 2Ln ) (Ln = Eu 4 , Gd 5 , Tb 6 , Dy 7 , Er 8 , DMAC = N , N ‐dimethylacetamide), have been prepared by solvothermal reactions of 2,5‐furandicarboxylic acid (H 2 FDCA) and KNO 3 with the corresponding lanthanide nitrate. X‐ray crystal structure analyses show that 1Ln possesses a 3D network based on the “16‐crown‐6‐like” secondary building unit (SBU), whereas 2Ln exhibits a 1D framework with a “23‐crown‐9‐like” SBU. The structural investigation unambiguously demonstrated that the lanthanide contraction affects the formation of 1Ln and 2Ln . Meanwhile, the solid‐state photoluminescent properties of 4 and 6 were also investigated at room temperature and the luminescence intensity of 4 is sensitive to small molecules.