Design of a Pyrene Scaffold Multifunctional Material: Real-Time Turn-On Chemosensor for Nitric Oxide, AIEE Behavior, and Detection of TNP Explosive

A dual-emission pyrene-based new fluorescent probe (N-(4-nitro-phenyl)-N′-pyren-1-ylmethyl-ene-ethane-1,2-diamine (PyDA-NP)) displays green fluorescence for nitric oxide (NO) sensing, whereas it exhibits blue emission in the aggregated state. The mechanism of nitric oxide (NO/NO⁺) sensing is based on N-nitrosation of aromatic secondary amine, which was not interfered by reactive oxygen species and reactive nitrogen species. The aggregation-induced enhancement of emission (AIEE) behaviors of the PyDA-NP could be attributed to the restriction of intramolecular rotation and vibration, resulting in rigidity enhancement of the molecules. The AIEE behavior of the probe was well established from fluorescence, dynamic light scattering, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, optical fluorescence microscopy, and time-resolved photoluminescence studies. In a H₂O/CH₃CN binary mixture (8:2 v/v), the probe showed maximum aggregation with extensive (833-fold) increases in fluorescence intensity and high quantum yield (0.79). The aggregated state of the probe was further applied for the detection of nitroexplosives. It displayed efficient sensing of 2,4,6-trinitrophenol (TNP), corroborating mainly the charge-transfer process from pyrene to a highly electron-deficient TNP moiety. Furthermore, for the on-site practical application of the proposed analytical system, a contact-mode analysis was performed.