Tryptanthrin incorporated spiropiperidine derivative as a fluorescent chemosensor for picric acid detection

The photophysical properties of a previously synthesized tryptanthrin incorporated spiropiperidine molecule (CTSP) is described. Studies revealed that the fluorescence of the compound gets significantly quenched by addition of picric acid (PA). The selectivity, anti-interference and quenching mechanistic studies are also described. The quenching mechanism was largely attributed to photo-induced electron transfer (PET) process facilitated by a strong electrostatic interaction between the protonated NH₂ group of CTSP and PA. Additionally, pH variations significantly influenced the quenching efficiency, with the highest response observed at neutral pH. These findings demonstrate that CTSP is a promising candidate for PA detection, with potential applications in environmental monitoring and security fields.