Rapid, Sensitive, and Selective "ON-OFF" Detection of Fe3+ Ions Using Novel Acetalophanes and Their Applications in Real Samples.

ABSTRACT

Three novel acetalophanes 1a-c have been designed, synthesized and characterized. The receptors 1b-c, featuring bulky anthracene groups, displayed significant selectivity for Fe3+ ions, resulting in a turn-off fluorescence mode in a DMF-buffer solution. Conversely, the non-steric probe 1a could serve as a versatile sensor for the simultaneous detection of Fe3+ and Cu2+ ions in MeOH-buffer solution. The sensing mechanism for the capability of 1a was demonstrated to be different, as evidenced by the addition of cyanide ions. The probes with Fe3+ exhibited a sensing mechanism that resulted in the deprotection of acetals to the corresponding starting materials, as confirmed by 1H NMR, IR spectra and TLC analysis. The attractive features of these practical and efficient sensors are selectivity, sensitivity (limit of detection = 0.15 µM by 1a, 0.16 µM by 1b and 0.14 µM by 1c), rapid response (less than 5 s). The on-site monitoring of various real samples, including well water, apricot, and green tea, proved to be successful for the quantitative and cost-effective detection of Fe3+. The method demonstrated good precision, even in the presence of other interfering materials.