Ultrasonic-assisted fabrication of F-MOFs: morphology and types of pillar-dependent sensing performance to phenolic NAC detection

Abstract

In this research, we designed two MOFs via an ultrasonic method to rectify some significant challenges, such as selective detection of particular nitroaromatic compounds in the presence of other NACs on selective sensing, and evaluated the effect of particle size on the sensing application of phenolic NACs. Here, two MOFs through the decoration of pore walls with CF₃ groups and π-conjugated ligands named as TMU-44 and TMU-45 (for Tarbiat Modares University) were successfully achieved under ultrasonic irradiation at ambient temperature and atmospheric pressure in various sonication time periods and reagent concentrations, followed by characterization via different techniques. The structure of TMU-44 contains phenyl rings with spindle morphology, whereas the aromatic structure of TMU-45 designed has a naphthyl ring with spherical morphology. Sensing properties of these materials for the detection of phenolic nitro aromatic compounds were studied. Measurements show that these MOFs with high surface area, small size and high porosity are sensitive to phenolic NACs in comparison with samples synthesized by the solvothermal method, in particular, 2,4,6-trinitrophenol with high quenching efficiency towards TMU-44 (K_SV = 48947 M⁻¹) and TMU-45 (K_SV = 57251 M⁻¹). The detection can be related to hydrogen bonding between the OH functional group of analytes and CF₃ groups of MOFs and π⋯π interactions between the π-conjugated structure of TMU-44 and TMU-45 and π-deficient ring of nitroaromatic compounds.