RESUMEN
In this work, a selective chemosensor, (E)-N'-((4-oxo-4H-chromen-3-yl)methylene)isoquinoline-1-carbohydrazide (ENO), was rationally developed for colorimetric and fluorogenic detection of Zn2+ ions. It was readily synthesized from 4-oxo-4H-chromene-3-carbaldehyde and isoquinoline-1-carbohydrazide via one-step Schiff reaction. ENO exhibited excellent fluorescent response performances toward Zn2+ over a wide pH range in EtOH/H2O media, including a distinguished color change from colorless to gold, a low limit of detection (LOD) value (34 nM), strong complexation ability (1.36 × 105 M-1) and rapid identification (2 min). The sensing mechanism of ENO toward Zn2+ was proposed on the basis of the chelation-enhanced fluorescence (CHEF) process, which was further supported by IR studies and the density functional theory (DFT) calculation. Moreover, ENO presented here demonstrated outstanding capability in monitoring trace level of Zn2+ ions in real water samples, living cells as well as the on-site assay kit.
Asunto(s)
Cromonas , Zinc , Colorantes Fluorescentes , Iones , Isoquinolinas , Espectrometría de Fluorescencia , AguaRESUMEN
The development of high-selective chemosensors for trace Al3+ detection in the ecosystem is crucially importance due to its detrimental effects. In this work, a simple Schiff-base fluorescent probe NPP derived from naphthalimide and picolinohydrazide was rationally designed and prepared for efficient detection of Al3+. NPP exhibited prominent sensing behaviors toward Al3+ with low detection limit (LOD) (39 nM), rapid response time (1 min), strong binding affinity (4.02 × 104), good anti-interference characteristics and visual detection. Binding ratio of NPP-Al3+ complex was determined to be 1:1 by Job's plot analysis. In addition, the chelation mechanism of NPP with Al3+ ions was proposed and substantiated by the density functional theory (DFT) and time-dependent density functional theory (TD-DFT), IR spectrum and 1H NMR titration experiments. Furthermore, this "signal-on" probe NPP was efficiently utilized as a promising indicator for Al3+ detection in environmental and biological samples.
Asunto(s)
Colorantes Fluorescentes , Naftalimidas , Aluminio/análisis , Ecosistema , Colorantes Fluorescentes/química , Iones , Microscopía Fluorescente , Naftalimidas/química , Espectrometría de Fluorescencia , AguaRESUMEN
Herein, a novel Schiff base fluorescent probe NIQ based on naphthalimide and iso-quinoline units has been readily prepared for the selective detection of Al3+ ions. The obviously visible color changes and prominent fluorescence enhancement were observed upon the addition of Al3+ to NIQ, which could be attributed to the complexation of NIQ with Al3+ and thus leading to the inhibition of photo-induced electron transfer (PET) and the chelation-enhanced fluorescence (CHEF) progress. The limit of detection (LOD) was 52 nM that was far below the standard recommended by the WHO. Binding ratio (1:1) of NIQ with Al3+ ions was supported by Job's plot. The binding constant of NIQ for Al3+ were calculated to be 3.27 × 105 M-1 on the basis of benesi-Hildebrand plot. The plausible binding mechanism for NIQ towards Al3+ ions was evidenced by the density functional theory (DFT) and 1H NMR titration experiment. Furthermore, this "turn-on" probe NIQ has been successfully applied as a biomarker for imaging the Al3+ ions in living cells.
Asunto(s)
Colorantes Fluorescentes , Naftalimidas , Aluminio , Iones , Espectrometría de FluorescenciaRESUMEN
A new Schiff base fluorescent probe NBP derived from the one-step condensation strategy of 2-butyl-6-hydroxy-1,3-dioxo-2,3-dihydro-1H-benzo[de]isoquinoline-5-carbaldehyde and N-(2-(hydrazinecarbonyl)phenyl)benzamide was synthesized and characterized. NBP exhibited high selectivity toward Al3+ along with naked-eye color changes and prominent fluorescence enhancement. The limit of detection (LOD) of NBP toward Al3+ was detected to be 80 nM. The binding ratio of NBP with Al3+ ions was obtained as 1 : 2 on the basis of Job's plot with the association constant Ka value of 4.22 × 1010 M-1/2. The plausible complexation mechanism of NBP toward Al3+ ions was validated by the density functional theory (DFT) and IR spectrum. In addition, in situ formed "NBP + Al3+" could be utilized as the second sensor for selective recognition of F-via fluorescence quenching with a low detection limit (44 nM). Furthermore, the cell imaging experiments of probe NBP in HeLa cells have successfully demonstrated that NBP could serve as an indicator for monitoring Al3+ ions in living cells. On top of that, NBP could be used to prepare simple test paper strips for quickly and qualitatively detecting a trace amount of Al3+ ions in a visible manner.