Fluorescent sensing and selective adsorption properties of metal–organic frameworks with mixed tricarboxylate and 1H-imidazol-4-yl-containing ligands

Abstract

Herein, two metal–organic frameworks (MOFs), [Co₄(μ₃-OH)₂(L)(BTB)₂(H₂O)₃]·5.6H₂O (1) and [Cd₃(L)₂(BTB)₂(μ₂-H₂O)]·7.4H₂O (2), based on 1,3-di(1H-imidazol-4-yl)benzene (L) and 1,3,5-tri(4-carboxyphenyl)benzene (H₃BTB), respectively, have been achieved. Compound 1 is a porous three-dimensional (3D) framework with butterfly-like tetranuclear clusters as 7-connected nodes, and compund 2 is a 3D net with a different topology. Remarkably, compounds 1 and 2 exhibit selective adsorption of CO₂ over N₂ and methyl orange (MO) dye molecules. Magnetic measurements reveal that there are antiferromagnetic interactions within the tetranuclear cluster in 1. Furthermore, 2 was well-dispersed in different solvents, and their luminescent properties were investigated, and the results indicated that 2 could be considered as a potential luminescent probe for the detection of ketone molecules.