Virender, Manpreet Kaur, Hari Om, Bakhtiyar Najafov, Ashok Kumar Sharma, Ismayil M. Garazade, M. Fátima C. Guedes da Silva, Armando J.L. Pombeiro, Wei Sun, Brij Mohan
Sensitive and portable detection of toxic metal ions is crucial for environmental monitoring and biomedical uses. We introduce a turn-on pyrene-based Schiff base chemosensor, ( E )-N-(4-methoxyphenyl)-1-(pyren-1-yl)methanimine ( MPM ), which selectively detects Mn 2+ and Pd 2+ ions with a 1:1 binding ratio. MPM shows strong binding affinities 6.840 × 10 6 M −1 for Mn 2+ and 1.240 × 10 7 M −1 for Pd 2+ , with detection limits below 10 −7 M, indicating high sensitivity. Insights into selectivity are provided through UV–visible, electrochemical, FT-IR, and NMR spectroscopy. Besides solution sensing, MPM also functions well in solid formats such as paper strips, silica matrices, and invisible fluorescent inks, supporting portable and security-related applications. Additionally, a smartphone-based fluorescence platform is developed for real-time, on-site detection of Mn 2+ and Pd 2+ , showing excellent linearity and recovery in spiked water/environmental samples. Overall, these results establish MPM as an affordable, adaptable sensor with significant potential for environmental monitoring, industrial quality control, and healthcare diagnostics.