Urea metal-organic frameworks as a highly selective fluorescent sensor for the explosive nitroaromatics and carbonyl compounds

Abstract

Currently, urea containing frameworks assumed to have a prominent role in the developing field of Y shapes anion detection such as TNP, TNT and their derivatives owing to their capability to act as double H-bond donors. Developing new and highly efficient sensors for detection of trace concentration of these explosives is remaining challenge. The immobilization of organic–functional struts within the pore wall of metal-organic frameworks (MOFs) is one of the new strategies to develop highly sensitive and selective receptors. Decoration of MOF skeleton with urea moiety can be helpful in effective recognizing of these specific guests for two reasons, (i) incorporation of urea strut in the framework prevents their inherent self-assembly and (ii) urea can form positive double hydrogen bond donation site which can act as a promising receptor for anionic moieties. A 3D, urea functionalized, TMU-18, has successfully synthesized as a chemosensor for selective detection by fluorescence signaling towards explosive nitroaromatics and carbonyl compounds. TMU-18 due to its special and porous structure and available functional group shows strong luminescence emission, and could be effectively used for sensitive detection of Trinitrophenol (TNP) with a 10 µM limit of detection (LOD).