Tripodal structured blue-green emissive fluorescent sensors for highly selective bifunctional detection: Their logic gate operations and real sample applications

The three novel tripodal-structured polyaromatic hydrocarbon-based fluorescent sensors which contain triazole as binding sites and naphthalene, anthracene, pyrene moieties as fluorophores (TN, TA, and TP) were synthesized via click chemistry and fully characterized by standard spectroscopic techniques. The photophysical and fluorescent sensor properties of TN, TA, and TP were investigated by UV-Vis electronic absorption, steady-state/time resolved/3-D fluorescence, and EEM-analysis spectroscopies. It was found that fluorescent sensors demonstrated excellent sensitivity and selectivity for Fe3+ ions over-tested other metal ions with significant fluorescence turn-off' responses which led to instant naked-eye and fluorescence color change. The binding mechanisms of TN, TA, and TP for F were evaluated with Job's plot and mass analysis. Moreover, treatment with H led to a sharp be increased in fluorescence intensities of TN, TA, and TP with turn-on fluorescence responses of Fe complexes ensembles. The obtained LODs (0.25-0.74 mu M) for iron ions were significantly lower than the tolerated limit of iron for drinking water by WHO/US EPA. The highly selective, time-saving, and sensitive fluorescence turn-off' responses of fluorescent sensors for Fe3+ ions were used for iron determination in environmental water samples. In addition, reversible fluorescence quenching responses of presented fluorescent sensors after addition of H were utilized for improvement of IMPLICATION logic gates.

Automated summary

The three novel tripodal-structured polyaromatic hydrocarbon-based fluorescent sensors were synthesized and characterized, showing excellent sensitivity and selectivity for Fe3+ ions in environmental water samples. The sensors demonstrated significantly low LODs for iron ions with highly selective and sensitive fluorescence turn-off responses.