A Transition Metal Schiff Base Coordination Compound as a Chemosensor for Sensitive Detection of 2,4,6-Trinitrophenol

In this study, a Schiff base-derived Pd(II) complex (L–Pd) was successfully synthesized and investigated as a fluorescent sensor for the detection of 2,4,6-trinitrophenol (TNP), a highly hazardous nitroaromatic explosive pollutant. Fluorescence studies demonstrated that the L–Pd complex exhibits strong emission properties and functions as an effective fluorescent probe for the sensitive detection of TNP through a fluorescence quenching mechanism in an ACN/H2O (2:3, v/v) medium. The complex displayed excellent sensing performance toward TNP, characterized by a high Stern–Volmer quenching constant (KSV = 20.7 × 103 M-1) and an exceptionally low limit of detection (LOD = 0.246 μM), highlighting its remarkable sensitivity. Furthermore, fluorescence titration experiments and Job’s plot analysis indicated a 2:1 complexation stoichiometry between L–Pd and TNP, indicating that two L–Pd molecules interact with a single TNP molecule during the recognition process. These results provide valuable insights into the sensing mechanism and molecular interactions responsible for the selective and sensitive determination of TNP. In conclusion, the present work introduces a high-performance Pd(II)-based fluorescent sensor for TNP detection and contributes to the development of advanced sensing materials for nitroaromatic explosives. Owing to its excellent sensitivity and selectivity, the developed sensing system holds considerable promise for applications in environmental monitoring, explosive detection, public safety, human health protection, and defense-related technologies.