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Chemical sensors for the rapid and selective detection of explosives such as 2,4,6-trinitrotoluene (TNT) are very important.

To study the influence of pore structural properties of metal−organic frameworks (MOFs) on drug adsorption and delivery, we synthesized two MOF termed TMU-6(RL1) {[Zn-(oba)(RL1) 0.5 ] n •(DMF) 1.5 } and TMU-21(RL2) {[Zn(oba)-(RL2) 0.5 ] n •(DMF) 1.5 } with amine basic N-donor pillars containing phenyl or naphthyl cores with various hydrophilic properties around the main center of the reaction. TG, IR, XPS, and PXRD analyses were used to extensively characterize the MOFs. The synthesized carriers showed high adsorption efficiency, stability, and controlled release. As an anticancer drug, Nimesulide (Nim) was adsorbed to MOFs using multiple adsorption mechanisms, such as Host π−π Guest interaction and Host N−H•••O Guest hydrogen bonds. Moreover, Hirshfeld surface analysis showed when the benzene core was replaced with the naphthalene core, the percentage of intermolecular interactions of π•••π and N•••H by amine sites in TMU-21( RL2) decreased compared with TMU-6(RL1), while the percentage of these interactions with guest molecules increased. The results showed that changes in the hydrophobicity/ hydrophilicity properties of MOFs would alter their ability to adsorb Nim in the pore of the frameworks. In vitro anticancer studies also showed that the cytotoxicity of Nim in MOFs@Nim composites against human cervical cancer cell line (HeLa cells) and human colon cancer cell line (HT-29 cells) is much higher than that of free Nim. Generally, based on the results, it can be said that the biological behavior of carriers can be regulated by adjusting the structure properties of MOFs.

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This study has developed a specific, easy, and novel approach to designing a sacrificial metal–organic framework (MOF) that can detect and measure the amount of Hg2+ in aqueous and nonaqueous solutions using the naked eye. The functionalized [Zn­(oba)­(RL3)0.5] n ·1.5DMF (TMU-59) provides the ability of simple visual assessment or colorimetric readout without sophisticated analytical equipment. Because of the special interaction with Hg2+, degradation of the structure of this unique MOF causes the solution to change color from colorless to a pink that is easily recognizable to the naked eye. The presence of a methyl group plays a major role in naked-eye detection by a qualitative sensor. Furthermore, this qualitative sensor data for the production of a simple, instant, and portable red, green, and blue (RGB)-based quantitative sensor were used to determine the concentration of Hg2+ in different specimens. As a turn-off fluorescence sensor, this unique structure is also capable of detecting Hg2+ at very low concentrations (the limit of detection is 0.16 ppb). To the best of our knowledge, TMU-59 is the first MOF-based naked-eye sensor that can successfully and specifically display the presence of Hg2+ through a major color change.