http://hdl.handle.net/10453/37629 2026-08-06T14:22:44Z http://hdl.handle.net/10453/195940 Title: Triazine based probes for nitroaniline: Comprehensive optical and DFT approach for dual-phase detection and fingerprint sensing. Authors: Shabbir, A; Iqbal, MM; Assiri, MA; Javid, T; Pervaiz, A; Khan, AH; Hassan, A; Shahzad, SA Abstract: 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. 2025-05-15T00:00:00Z http://hdl.handle.net/10453/195932 Title: Synthesis and development of indanone as AIE based fluorescent probe for ultrasensitive detection of 4-nitroaniline in solid and vapor phase Authors: Sajid, Q; Muqadas,; Shabbir, A; Khan, AM; Assiri, MA; Rauf, W; Shahzad, SA Abstract: A new indanone-based fluorescent probe PDI was rationally designed and synthesized, exhibiting pronounced solvatochromic behavior and aggregation-induced emission (AIE) in aqueous medium. The probe PDI displayed enhanced fluorescence emission accompanied by a distinct bathochromic shift within the absorption and emission profiles, demonstrating the formation of J-aggregates. Owing to these remarkable photophysical properties, probe PDI served as a reliable fluorescent sensor for detection of 4-NA with selective quenching response via a photoinduced electron transfer (PET) mechanism. The interaction mechanism between PDI and 4-NA was investigated through 1H NMR titration, mass spectrometry (LC-MS) titration, dynamic light scattering (DLS), FTIR titration, and density functional theory (DFT) analysis. Probe PDI exhibited significant fluorescence quenching toward 4-NA, with a calculated limit of detection (LOD) of 196 nM. In addition to solid phase detection of 4-NA, probe PDI was effectively utilized for vapor-phase sensing of 4-NA, TFA and TEA. Furthermore, the applicability of probe PDI was extended to the construction of logic gate, highlighting its potential for impactful point-of-need applications in pollutant sensing and molecular device development. 2025-12-01T00:00:00Z http://hdl.handle.net/10453/195931 Title: Synthesis and construction of AIE based fluorescent sensor for highly selective solid phase sensing of 4-nitroaniline: solvatochromism, acidochromism, mechanochromism and applications in latent fingerprints and invisible ink Authors: Muqadas,; Shabbir, A; Khan, M; Assiri, MA; Khan, AM; Shahzad, SA Abstract: Highly selective fluorescent sensor 2-(4-diethylamino)benzylideneamino)-3′,6′-dihydroxyspiro[isoindoline-1,9′-xanthen]-3-one (DDX) with a rotationally labile aryl group was developed for the selective detection of 4-nitroaniline (4-NA). Sensor DDX was synthesized and characterized using NMR spectroscopy. Sensor DDX exhibited notable photophysical properties including solvatochromism, aggregation-induced emission (AIE) with J-aggregates formation, reversible mechanochromism character and acidochromism behavior. Sensor DDX selectively detects 4-nitroaniline (4-NA) through fluorescence quenching in the presence of a wide range of competing analytes. The sensing of 4-NA is attributed to photoinduced electron transfer (PET) mechanism. Sensor DDX exhibits the limit of detection (LOD) as low as 157 nM. Various techniques including UV visible, fluorescence spectroscopy, 1H NMR, Job’s plot, dynamic light scattering (DLS) along with theoretical calculations were performed to confirm the exceptional selectivity of the sensor DDX towards 4-NA. Additionally, sensor DDX was effectively employed for the solution and solid phase sensing of 4-NA. The developed sensor DDX is efficiently utilized for the fabrication of hand-held fluorescent kits for on-site detection of 4-NA and latent fingerprints (LFPs) on porous as well as non-porous surfaces. Moreover, sensor DDX has been employed as an invisible ink to demonstrate impactful point-of-need applications of the proposed sensor. 2025-07-01T00:00:00Z http://hdl.handle.net/10453/195881 Title: Groomers and Trigger-Happy Thugs? Public Sector Stereotypes of Teachers and Police Officers Authors: Szydlowski, G; Mousseau, V; Charbonneau, É Abstract: In an era where memes and social media cross national borders, stereotypes can jump from one country to another. We tested the level of support for two public sector stereotypes from the United States in one Canadian province. A representative sample of 3,510 Quebecers answered questions about their public sector stereotypes, for teachers (n = 1,494) and police officers (n = 1,516). Although the support for the teacher as a groomer and police officers as trigger-happy is lower and less polarized than in the original studies in the United States, the profiles of citizens who support these stereotypes are similar. 2025-06-01T00:00:00Z