Supramolecular Ionic Nanomaterials via Ionic Self-Assembly with High Thermal and Water Stability for the Detection of Trinitrophenol

Two supramolecular ionic nanomaterials (SINs) were successfully prepared by multidentate imidazolium organic salts and multidentate acid via ionic self-assembly (ISA), which is formed by tetraphenylethylene (TPE)-based organic salts (TPE-COS and TPE-C 16 OS) and 4,4′,4″,4‴-(ethene-1,1,2,2-tetrayl)tetrabenzenesulfonic acid (TPE-SO 3 H) in MeOH. These SINs exhibited high thermal stability and are insoluble in solvents. Furthermore, as fluorescence sensors, they showed high sensitivity and selectivity in the detection of nitroaromatic explosives, especially for trinitrophenol (TNP); the linear range of SIN-1 and SIN-2 was 0.4–128 μM and 1–128 μM; their λex was set as 340 and 350 nm; λem was 489 and 458 nm; and the related limit of detection was 0.87 and 0.42 μM, respectively. The quenching mechanism of TNP for SINs is the synergistic effect of the energy transfer, the inner filter, and photoelectron transfer.