MOF matrix doped with rare earth ions to realize ratiometric fluorescent sensing of 2,4,6-trinitrophenol: Synthesis, characterization and performance

Abstract

2,4,6-trinitrophenol (PA) is a well-known aromatic compound, due to their higher explosive energy than TNT and their wide utilization when producing organic dyes, medicines and antiseptics. The following paper constructed a composite optical sensing system (denoted as Tb:Eu@MOF) for PA detection using [Zn8(ad)4(BPDC)6O·2 Me2NH2]·G, ad = adenine, BPDC = 4,4′-biphenyl dicarboxylic acid, G = DMF and water, as supporting matrix and two rare earth ions, Tb(III) and Eu(III), as dopant. Tb:Eu@MOF was carefully characterized by means of micromorphology, XRD, N2 adsorption and desorption. Detailed analysis on its photophysical performance indicated weak Tb emission and strong Eu emission, owing to the energy competing between two kinds of rare earth ions in Tb:Eu@MOF. After meeting PA, such energy competing was blocked, leading to enhanced Tb emission and decreased Eu emission. Ratiometric fluorescent sensing for PA detection was thus constructed with good selectivity and low LOD (limit of detection) of 0.87 μM. Linear sensing response was achieved. Its practical sensing application and naked eye detection for PA were tentatively discussed as well.