Syntheses, Crystal Structures and Luminescent Properties of Two Lanthanide Coordination Polymers Based on Bifunctional Ligand

摘要

Two lanthanide coordination polymers,[Eu(HL)(L)(H2O)2]n (1) and [Tb(H0.5L)2]n (2),based on bifunctional 5-(1H-imidazol-l-yl) isophthalic acid (H2L),are hydrothermally synthesized and characterized by both single-crystal and powder X-ray diffraction analyses,and FT-IR.In compound 1,the basic inorganic building unit of the coordination network is the dinuclear [Eu2(COO)6] cluster.Each [Eu2(COO)6] cluster connects four HL ligands and each HL-ligand links two [Eu2(COO)6] clusters,resulting in a 2D coordination layer.The adjacent 2D layers are further connected via neighboring inter-layer hydrogen bonds to give a 3D supramolecular structure.In compound 2,the Tb3+ is coordinated to six oxygen atoms.Each Tb3+ ion connects six ligands and each ligand links three Tb3+ ions,leading to a 3D coordination polymeric network which exhibits remarkably high thermal stability up to 500 ℃.Furthermore,due to the successful incorporation of Tb3+,compound 2 displays characteristic luminescent emission in the solid state at room temperature.The combination of high thermal stability and fluorescent property of compound 2 would make it as a promising light-emitting material.