A New Fluorescent Chemosensor for Cobalt(II) Ions in Living Cells Based on 1,8-Naphthalimide

Abstract

In this work, a highly selective fluorescent chemosensor N-(2-(2-butyl-1,3-dioxo-2,3-dihydro-1H-benzo[de]isoquinolin-6-yl)hydrazine-1-carbonothioyl)benzamide (L) was prepared and characterized. An assay to detect the presence of cobalt(II) ions was developed by utilizing turn-on fluorescence enhancement with visual colorimetric response. Upon treatment with Co2+, a remarkable fluorescence enhancement located at 450 nm was visible to naked eyes accompanied with a distinct color change (from pink to colorless) in a CH3CN/HEPES (4/1, v/v, pH = 7.4) solution due to the formation of a 1:1 complex at room temperature. In addition, the linear concentration range for Co2+ was 0–25 µM with the limit of detection down to 0.26 µM. Thus, a highly sensitive fluorescent method based on chelation-assisted fluorescence enhancement was developed for the trace-level detection of Co2+. The sensor was found to be highly selective toward Co2+ ions with a large number of coexisting ions. Furthermore, the L probe can serve as a fluorescent sensor for Co2+ detecting in biological environments, demonstrating its low toxic properties to organisms and good cell permeability in live cell imaging.

Recent trends in chemistry, structure, and various applications of 1-acyl-3-substituted thioureas: a detailed review

“…Liu et al 96 synthesized a fluorescent chemosensor N -(2-(2-butyl-1,3-dioxo-2,3-dihydro-1 H -benzo[de]isoquinolin-6-yl)hydrazine-1-carbonothioyl)benzamide 119 and characterized it by spectroscopic methods Scheme 54 . This chemosensor was designed for the selective detection of Co 2+ ions Scheme 55 .…”

2,7-Naphthyridine based colorimetric and fluorescent “Turn Off” chemosensors for selective detection of Ni(II) in aqueous media

“…The sharp peaks present at 3420, 3294 and 3109 cm -1 due to NH stretching frequencies in free receptor L4 were broadened by adding Ni 2+ , suggesting the involvement of NH 2 group in coordination with Ni 2+ to form complex. 39 Metal ion selectivity An important feature of receptor L4 is to examine its selectivity towards analyte by competitive titration experiments (Figure 6). The intensity of absorption band at 537 nm due to complex formation of L4- The UV-visible absorption spectra of L4-Ni 2+ complex with various anions was recorded to check the stability of complex, no change in absorption band at 537 nm was observed (Figure 7).…”

Microwave-assisted one-pot multicomponent synthesis of indole derived fluorometric probe for detection of Co2+ ions

“…Hence fluorescence quenching is suppressed due to lowering of HOMO energy which makes PET not possible any further (Valeur and Leray, 2000). The changes in the charge density on the N-binding site of the ligand after coordinating with Co 2+ inhibit the PET mechanism (Liu et al, 2019). The rigidity of the L-Co 2+ complex is higher than to the free ligand, which gives rise to the Chelation enhanced fluorescence (Liu et al, 2019).…”

“…The changes in the charge density on the N-binding site of the ligand after coordinating with Co 2+ inhibit the PET mechanism (Liu et al, 2019). The rigidity of the L-Co 2+ complex is higher than to the free ligand, which gives rise to the Chelation enhanced fluorescence (Liu et al, 2019). The fluorescence enhancement of Co 2+ with the ligand is a special case scenario because Co 2+ is a paramagnetic metal ion with a d 7 configuration which normally quenches the intrinsic fluorescence.…”