Triazine based probes for nitroaniline: Comprehensive optical and DFT approach for dual-phase detection and fingerprint sensing

Extended conjugation in fluorescent probes is crucial for efficient optical characteristics. Herein, two novel triazine based organic compounds ITA and DIT with extraordinary photophysical properties were synthesized through palladium catalyzed Suzuki and Sonogashira coupling reactions, respectively. Solvatochromism and solid-state based comprehensive study of photophysical properties of probes ITA and DIT was investigated for developing dual phase and extremely sensitive and selective fluorescent probes for detection of 4-nitroanilne (4-NA). The probes ITA and DIT were also utilized in the formulation of latent fingerprint sensing and invisible ink. Furthermore, the outstanding fluorescence properties of probes ITA and DIT were efficiently used for the selective sensing of 4-nitroanilne (4-NA) in real samples and portable paper-strips were constructed for the on-site sensing of 4-NA. The sensing approach for selective detection of 4-NA was comprehensively evaluated with the help of spectroscopic analysis including titration NMR, UV–visible spectroscopy, fluorescence studies, dynamic light scattering (DLS) and DFT calculations. DFT calculations included the calculation of RDG analysis, thermodynamic stability, charge transfer and molecular orbital studies as well as QTAIM. All the analysis and theoretical studies supported the existence of non-covalent interactions between probes and 4-NA.