Application of aza-BODIPY as a Nitroaromatic Sensor

Nitroaromatic explosive detection with high sensitivityand selectivityis requisite for civilian and military safety and the ecosystem. Inthis study, aza boron dipyrromethene (aza-BODIPY) dye was selectedas a fluorescent-based chemosensor against nitroaromatic compounds(NACs) including 2,4,6-trinitrophenol (picric acid, TNP), 2,4,6-trinitrotoluene(TNT), and 2,4-dinitrotoluene (DNT). This dye molecule exhibits sharpfluorescent behavior with high quantum yields beyond the near-infraredregion (NIR) and is considered as a potential candidate for the detectionof NACs. O'Shea's approach was used to synthesize tetraphenyl-conjugatedaza-BODIPY molecules. Quenching of fluorescence emission of aza-BODIPYat 668 nm after the exposure to NACs was investigated under acetonitrile-waterand acetonitrile-ethanol solvent conditions. The quenchingresponses and its mechanism were examined by considering the Stern-Volmerrelationship Stern-Volmer constants (K (sv)) for TNP (in water), TNP (in ethanol), TNT, and DNT, whichare predicted to be 1420, 1215, 1364, and 968 M-1, respectively, all of which are sufficiently above the limit ofdetection (LOD) values. Thus, the present study opens up the possibilityof the usage of aza-BODIPY molecules as a low-cost, light-weight sensorfor the detection of NAC explosives.