The mixed-ligand strategy to assemble a europium metal-organic framework with a 2-fold-interpenetrated network

Abstract

A novel europium complex with the mixed ligands of 1-methyl-3,5-bis(4′-carboxy-phenyl)-1,2,4-triazole (mbcpt) and p-phthalic acid (pa), [Eu2Cl2(H3O)2(μ4-mbcpt)2(μ4-pa)]n (1), has been synthesized under the solvothermal conditions and structurally characterized by single-crystal X-ray diffraction. Complex 1 exhibits a three-dimensional (3-D) metal-​organic framework. The 3-D open framework features a 2-fold-interpenetrated network. Solid-state diffuse reflectance spectroscopy uncovers the presence of a wide optical band gap of 3.56 eV, indicating that it is a wide band gap organic semiconductor material. Solid-state photoluminescence measurement reveals that complex 1 shows red light emission bands locating at 602, 611, 642 and 690 nm, which can be assigned to the 5D0 → 7FJ (Eu3+) with the value of J = 1, 2, 3 and 4, respectively. Magnetic measurements reveal that complex 1 shows an antiferromagnetic behavior.