(AGENPARL) – LONDON (UNITED KINGDOM), lun 28 settembre 2020
A new 8-hydroxyquinoline derivative bearing the hydroxytetraphenylethene moiety called TPE(OH)-8HQ has been designed, synthesized and evaluated as an efficient fluorescence “turn-on” sensor for detection of Zn2+ based on chelation-enhanced fluorescence (CHEF) mechanism in neutral aqueous solution. The free sensor displays a weak fluorescence emission at 470 nm, upon addition of Zn2+, its emission peak was red-shifted from 470 nm to 607 nm and the emission intensity at 607 nm was increased by 17-fold, which performed fluorescence “turn-on” recognition for Zn2+ without interference from same group elements such as Cd2+/Hg2+. Moreover, TPE(OH)-8HQ achieved a low detection limited of 1.64 × 10-7 M, and it exhibited a large Stokes shift (289 nm) after the addition of zinc ions which were effectively eliminating background interference for live cell imaging. Through the control experiments using two analogous without hydroxyl in the TPE of TPE-8HQ and TPE(OCH3)-8HQ, we find out that these two analogous can not distinguish Zn2+ from Cd2+, revealing that the hydroxyl group of TPE bonding interactions with Zn2+ are crucial for selectively detect Zn2+ ions. Additionally, the mechanism of interaction process between TPE(OH)-8HQ and Zn2+ had been studied in detail by UV/ fluorescence titration and NMR analysis. Job’s plot and mass spectrometry experiment analysis indicated that TPE(OH)-8HQ formed a 2:1 complex with Zn2+. More importantly, TPE(OH)-8HQ has been successfully used for imaging Zn2+ in living cells and fabrication of simple device test strips for on-site and rapid sensing of Zn2+ ions in aqueous solution.
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