Selective luminescent sensing of teflubenzuron and oxyfluorfen by a resorcin[4]arene-based metal-organic framework

Abstract

In this work, a new resorcin[4]arene-based metal–organic framework, [Zn4L(H2O)10]·10H2O, has been synthesized by incorporating Zn(II) cations and a dodecacarboxylic-functionalized resorcin[4]arene (H12L) ligand. The structure of [Zn4L(H2O)10]·10H2O was characterized using a single-crystal X-ray diffraction technique. The two-dimensional layered structures were linked to adjacent layers by hydrogen bonds to form a three-dimensional supramolecular architecture. [Zn4L(H2O)10]·10H2O exhibits excellent stability in water and various organic solvents, therefore, it was used as a luminescent probe to detect pesticides, such as teflubenzuron and oxyfluorfen. Teflubenzuron can significantly enhance the luminescence intensity of [Zn4L(H2O)10]·10H2O due to the hydrogen bond interaction, whereas oxyfluorfen can decrease the luminescence intensity of [Zn4L(H2O)10]·10H2O, which is attributed to the charge transfer and energy transfer. The luminescence mechanism was supported by the density functional theory calculations. The limit of detection for teflubenzuron and oxyfluorfen was 0.18 μM and 4.08 μM, respectively.