Synthesis of AIEE active triazine based new fluorescent and colorimetric probes: A reversible mechanochromism and sequential detection of picric acid and ciprofloxacin

Two new triazine based multifunctional fluorescent probes T1 and T2 were synthesized that displayed excellent aggregation induced emission enhancement (AIEE) and reversible mechanochromic character. The AIEE active probes were used for selective fluorescence detection of picric acid (PA) based on fluorescence quenching response. The sensitive detection of PA was achieved through electron and charge transfer between them resulting in the formation of the probe-PA complex. The limits of detection of T1 and T2 for PA were calculated as 1.94 and 2.24 nM, respectively. Subsequently, probe-PA complexes acted as fluorescence enhancement base probes for sequential detection of an antibacterial drug, ciprofloxacin (CIP). The sensitivity (detection limit) of the probe-PA complexes for the recognition of ciprofloxacin was determined as 3.16 and 4.46 nM. Hence, a new strategy was successfully developed for the sensing of ciprofloxacin (CIP). The proposed mechanism for the sensing of PA and ciprofloxacin was evaluated through H-1 NMR titration, DLS, and DFT analyses. Meanwhile, probes manifested colorimetric identification of PA and CIP. Advantageously, probe-PA complexes were applied in urine samples for the quantification of ciprofloxacin. Moreover, application in real water samples revealed that the spiked recoveries of PA were attained as > 90%. To the best of our knowledge, it is the first report where triazine based fluorescent probes showed excellent simultaneous responses towards force stimuli (mechanochromism), picric acid, and ciprofloxacin.

Automated summary

Two new triazine based fluorescent probes were synthesized and showed excellent responses towards force stimuli, picric acid, and ciprofloxacin. The probes were used for selective fluorescence detection of picric acid, followed by the detection of ciprofloxacin using the probe-picric acid complexes as fluorescence enhancement probes. The proposed mechanism for the sensing of picric acid and ciprofloxacin was evaluated through various analyses. The probes also demonstrated colorimetric identification and were successfully applied in urine and water samples.