Abstract
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•A simple carbazole derived Schiff base chemosensor C1 was synthesized and utilized as a fluorescent chemosensor for sequential detection of Fe3+ and Arginine.•The sensor C1 exposes specific response toward Fe3+ and Arginine over various potentially competing cations and amino acids.•An intramolecular charge transfer (ICT) based sensing approach has been confirmed upon the binding of Fe3+ with efficient fluorescence quenching.•Nanomolar detection limit of 12.22 × 10−9 M is achieved for Fe3+ detection.•For application point of view, on-site monitoring, Logic gate and living cells fluorescence imaging were additionally investigated.
A simple carbazole derived Schiff base fluorescent chemosensor (C1) has been synthesized and characterized successfully to recognize sequentially Fe3+ ion and an amino acid, arginine (Arg). The chemosensor (C1) shows specific response “on–off-on” towards Fe3+ and Arg among different competing cations and amino acids. Interestingly, the fluorescence emission got turned-off for C1-Fe3+ complex and turned-on for the detection of arginine. The binding ability of sensor C1 with Fe3+ and arginine was advocated using fluorometric titrations, Job’s plot, B-H plot and density functional theory studies (DFT). The significant color changes of sensor C1 from aqua blue to transparent blue to aqua blue were monitored under UV-lamp of 365 nm during the sensing process, which additionally supported the complex formation. The sensor C1 accomplishes the lowest detection limit of 12.22 × 10−9 M and binding constant of 2.09 × 104 M−1 for Fe3+ detection. This efficient fluorescent candidate was utilized for the detection of Fe3+ in applications such as molecular logic gate, smart-phone based on-site detection, live cell bio-imaging and real sample analysis.