科研之友
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摘要
2-(6-hydroxynaphthalen-2-methylene) malononitrile (probe 1) was synthesized by means of the reaction of malononitrile and 6-hydroxy-2-naphthaldehyde, and the product was used as a fluorescent probe for the detection of fluoride ions. The results show that, in the detection system, the DMSO solution of probe 1 is pale yellow without fluorescence, and it immediately turns to be pink with blue-fluorescence after adding fluoride ions but shows no fluorescence after adding other anions. It is also found that probe 1 exhibits strong selectivity and high sensitivity to fluoride ions. According to the evaluation of the Job's plot, the ratio of probe 1 to fluoride ions in the complex is found to be 1:1. The1H NMR titration results confirm that the deprotonation of phenolic hydroxyl of probe 1 occurs after adding fluoride ions. The calculation results based on the Frontier molecular orbital theory indicate that the HOMO-LUMO energy gap of probe 1 increases after the deprotonation, and the color of solution and the fluorescence spectrum change dramatically.
