Terbium-benzoyl acetate complex encored indium-MOFs through post-synthetic modification for luminescent sensitive detection of organophosphorus insecticides

Abstract

Metal-organic frameworks (MOFs) are represented ideal candidate materials for chemical sensing of different kinds of species because they contain optically active sites may be in organic linker or ions node, moreover, MOFs have high porosity that capture different types of guests. Lanthanide MOFs (Ln-MOFs) was very common in sensing chemical species due to identical light emission characteristics. The problem of Ln-MOFs was the difficulty of its preparation; therefore, post-synthetic modification (PSM) technique was excellent for incorporation of lanthanide site in the network. Unlike other MOFs, In-MOF can be post-synthesized because of its free amino group in the network, therefore, it was chosen in the current work. Here, Tb-In-MOF-EBA was generated by PSM of In-MOF in two steps: (1) formation of the amide by the reaction of In-MOF with ethyl benzoyl acetate; (2) chelation of Tb3+ cations by the diketone fragment. The main challenge of present work is not to give another luminescent MOF based sensor rather than using decorative technique based PSM route to tune optically active sensors for organophosphorus (OP) insecticides (dimethoate, chlorpyrifos, and pirimiphos-methyl) identification quantitatively and qualitatively. The emission intensity of Tb-In-MOF-EBA were reduced with 8 %, 50 %, and 81 %, after adding dimethoate, chlorpyrifos, and pirimiphos-methyl for the parent compounds, respectively. Tb-In-MOF-EBA showed interesting selectivity toward dimethoate, chlorpyrifos, pirimiphos-methyl, therefore, it can be used in measuring the concentration of OP insecticide with high accuracy.