A rhodamine-bistriazole based fluorescent and colorimetric sensor containing a phenyl linker for Fe(III) detection

A rhodamine-based fluorescent sensor bearing 1,2-phenylenediamine linked to a bistriazole moiety was designed and synthesized through the copper(I)-catalyzed click chemistry. The bistriazole-based sensor containing an aromatic linker was highly selective toward Fe3+, among other metal ions in MeCN/H2O (1:9 v/v, pH 7.0). Upon the addition of Fe3+, the solution of the sensor changed from colorless to pink and fluorescence emission increased 614-fold, visually observed within 5 min. For the titration experiments, the absorption and fluorescence intensity were distinctly enhanced with the increasing concentrations of Fe(3+)and the limit of detection (LOD) was calculated to be 0.15 mu M. The binding ratio of the sensor-Fe(3+)complex was a 1:1 ratio, confirmed by the Job's plot. Besides, the optimized condition of the sensor for Fe(3+)recognition was investigated in a pH range of 5.0-7.0.

Automated summary

A rhodamine-based fluorescent sensor with high selectivity towards Fe3+ was designed and synthesized, exhibiting a 614-fold increase in fluorescence emission upon Fe3+ binding. The detection limit for Fe3+ was determined to be 0.15 μM, with a 1:1 binding ratio between the sensor and Fe3+ confirmed by Job's plot.