A Fluorene based Fluorogenic ''Turn-off'' Chemosensor for the Recognition of Cu2+ and Fe3+: Computational Modeling and Living-cell Application

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Author(s): Sukriye Nihan Karuk Elmas, Duygu Aydin, Tahir Savran, Eray Caliskan, Kenan Koran, Fatma Nur Arslan, Gokhan Sadi, Ahmet Orhan Gorgulu, Ibrahim Yilmaz*

Journal Name: Current Analytical Chemistry


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Abstract:

Background: The traditional methods for the detection and quantification of Cu2+ and Fe3+ heavy metal ions are usually troublesome in terms of high-cost, non-portable, time-consuming, specialized personnel and complicated tools, so their applications in practical analyses is limited. Therefore, the development of cheap, fast and simple-use techniques/instruments with high sensitivity/selectivity for the detection of heavy metal ions is highly demanded and studied.

Methods: In this study, a fluorene-based fluorescent ''turn-off'' sensor, methyl 2-(2-((((9H-fluoren-9- yl)methoxy)carbonyl)amino)-3- phenylpropanamido) acetate (probe FLPG) was synthesized via onepot reaction and characterized by 1H-NMR, 13C-APT-NMR, HETCOR, ATR-FTIR and elemental analysis in detailed. All emission spectral studies of the probe FLPG have been performed in CH3CN/HEPES (9/1, v/v, pH=7.4) media at rt. The quantum (Φ) yield of probe FLPG decreased considerably in the presence of Cu2+ and Fe3+. The theoretical computation of probe FLPG and its complexes were also performed using density functional theory (DFT). Furthermore, bio-imaging experiments of the probe FLPG was successfully carried out for Cu2+ and Fe3+ monitoring in living-cells.

Results: The probe FLPG could sense Cu2+ and Fe3+ with high selectivity and sensitivity, and quantitative correlations (R2>0.9000) between the Cu2+/Fe3+ concentrations (0.0−10.0 equiv). The limits of detection for Cu2+ and Fe3+ were found as 25.07 nM and 37.80 nM, respectively. The fluorescence quenching in the sensor is managed by ligand-to-metal charge transfer (LMCT) mechanism. Job’s plot was used to determine the binding stoichiometry (1:2) of the probe FLPG towards Cu2+ and Fe3+. The binding constants with strongly interacting Cu2+ and Fe3+ were determined as 4.56×108 M-2 and 2.02×1010 M-2, respectively, via the fluorescence titration experiments. The outcomes of the computational study supported the fluorescence data. Moreover, the practical application of the probe FLPG was successfully performed for living cells.

Conclusion: This simple chemosensor system offers a highly selective and sensitive sensing platform for the routine detection of Cu2+ and Fe3+, and it keeps away from the usage of costly and sophisticated analysis systems.

Keywords: Fluorescence sensor, fluorene, iron, copper, DFT, bio-imaging.

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Article Details

Published on: 22 March, 2021
(E-pub Ahead of Print)
DOI: 10.2174/1871520621666210322112005
Price: $95

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