“Turn-On” fluorescent chemosensor based on β-diketone for detecting Th4+ ions in Aqueous Solution and application in living cell imaging

•An efficient β-diketone derivative-based fluorescent sensor for Th4+ detection was designed and synthesized.•The fluorescent sensor displays a high selectivity and good sensitivity for Th4+ ions even in the present of UO22 + , which the LOD was 0.0344  μM.•This fluorescent sensor was successfully applied for the detection of Th4+ in living cells imaging.•The nature of interactions between the Hn and Th4+ and its fluorescent mechanism were supposed.•The rate of water in the solvent was more than previous reports.

A fluorescent sensor Hn based on β-diketone derivative for Th4+ ions was designed and investigated, which showed high selectivity in the present of other metal ions even UO22+ in CH3OH:H2O (v/v = 2:8, pH = 7.2) solution. Meanwhile, the binding mode of the sensor Hn with Th4+ ions was found to be 1:1 with association constant of 2.46 × 104 M−1. And there was linear relationship between the fluorescent intensity of Hn-Th4+ and the concentration of Th4+ ions covering a range of 0.06 μM-1.0 μM and the detection limit was 0.0344 μM. At the same time, the interaction properties between the sensor Hn and Th4+ ions and the fluorescent mechanism were investigated by IR, 1HNMR and DFT. Most importantly, this fluorescent sensor was successfully utilized for the fluorescent imaging of Th4+ ions in living cells.

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