An On–Off–On Fluorescence Probe Based on Coumarin for Cu2+, Cysteine, and Histidine Detections

A simple coumarin-based Schiff base (probe L) was successfully developed. It showed strong green fluorescence emission at 527 nm with a 70.3% of fluorescence quantum efficiency (ΦF). However, after the addition of common metal ions, probe L can only combine with Cu2+ ions and displayed significant fluorescence quenching of > 96.2% (ΦF = 2.7%) due to the paramagnetic quenching action from Cu2+. Conversely, by the coordination action of cysteine (Cys) and histidine (His), the quenching fluorescence of the complex (L-Cu2+) between probe L and Cu2+ ions was recovered mostly because the Cys and His can usurp Cu2+ of L-Cu2+ and led to the liberation of probe L. Based on the fluorescence changes of probe L with the actions of Cu2+, Cys, and His, an on–off–on reversible fluorescence probe for sensitive and specific monitoring Cu2+, Cys, and His has been prepared. More importantly, the probe L and L-Cu2+ ensemble can be used, respectively, to test Cu2+ and Cys/His in live cells and human urine samples with great reliability.

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A Novel Near-Infrared Fluorescence Sensor for H2O2 Based on N-Acetyl-L-Cysteine-Capped Gold Nanoparticles

Journal of Nano Research ◽

10.4028/www.scientific.net/jnanor.46.234 ◽

2017 ◽

Vol 46 ◽

pp. 234-240

Author(s):

Wen Juan Dong ◽

Ji Yan Han ◽

Xin Wu ◽

Li Fan ◽

Wen Ting Liang

Keyword(s):

Hydrogen Peroxide ◽

Gold Nanoparticles ◽

Fluorescence Quenching ◽

Near Infrared ◽

Fluorescence Probe ◽

Fluorescence Emission ◽

Excitation Wavelength ◽

Experimental Conditions ◽

Time Resolved ◽

Near Infrared Fluorescence

A novel near-infrared fluorescence quenching method has been developed for the determination of hydrogen peroxide based on N-acetyl-L-cysteine-capped gold nanoparticles (NAC-AuNPs) as a fluorescence probe. The prepared gold nanoparticles with the size of about 1.91 nm exhibited strong near-infrared fluorescence emission at 693 nm with excitation wavelength at 450 nm in aqueous solution. The fluorescence intensity of NAC-AuNPs was quenched dramatically by adding hydrogen peroxide. Therefore, it could be used to detect hydrogen peroxide based on the fluorescence quenching intensity was linear with the concentration of hydrogen peroxide. Under the optimal experimental conditions, the linear range and detection limit were 1.0×10-6 –3.0×10-2 mol/L and 1.0×10-7 mol/L, respectively. The possible quenching mechanism was investigated by time-resolved fluorescence spectroscopy. The proposed method was simple, sensitive and showed good repeatability and stability.

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Spectroscopic Investigation of Fluorescence Quenching Agents. Part II: Effect of Nitromethane on the Fluorescence Emission Behavior of Thirty-Six Alternant Benzenoid Polycyclic Aromatic Hydrocarbons

Applied Spectroscopy ◽

10.1366/0003702924123872 ◽

1992 ◽

Vol 46 (8) ◽

pp. 1260-1265 ◽

Cited By ~ 37

Author(s):

Sheryl A. Tucker ◽

Hardjanti Darmodjo ◽

William E. Acree ◽

John C. Fetzer ◽

Maximilian Zander

Keyword(s):

Polycyclic Aromatic Hydrocarbons ◽

Fluorescence Quenching ◽

Aromatic Hydrocarbons ◽

Spectroscopic Investigation ◽

Fluorescence Probe ◽

Fluorescence Emission ◽

Solvent Polarity ◽

Polycyclic Aromatic ◽

Emission Behavior ◽

Emission Intensity Ratio

Nitromethane is examined as a selective quenching agent for discriminating between “alternant” versus “nonalternant” polycyclic aromatic hydrocarbons in unknown mixtures. Of the 36 benzenoid solutes studied, only dibenzo[hi,wx]heptaphene failed to obey the selective quenching rule. Also reported are new experimental fluorescence probe studies for dibenzo[de,st]pentacene, dibenzo[fg,qr]pentacene, naphtho[8,1,2hij)-hexaphene, benzo[vwx]hexaphene, benzo[1,2,3cd;4,5,6c'd‘]diperylene, dibenzo[hi,wx]heptacene, benzo[b]triphenylene, chrysense, and anthracene dissolved in nonelectrolyte solvents of varying polarity. Benzo-[vwx]hexaphene was found to exhibit probe character, as evidenced by a systematic variation in emission intensity ratio with solvent polarity.

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Synthesis of Fluorescent Nitrogen-Doped Carbon Quantum Dots for Selective Detection of Picric Acid in Water Samples

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2018.16342 ◽

2018 ◽

Vol 18 (12) ◽

pp. 8111-8117 ◽

Cited By ~ 5

Author(s):

Min Tian ◽

Yingte Wang ◽

Yong Zhang

Keyword(s):

Fluorescence Quenching ◽

Fluorescence Probe ◽

Picric Acid ◽

Fluorescence Emission ◽

Excitation Wavelength ◽

Selective Detection ◽

Blue Fluorescence ◽

Nitrogen Doped ◽

Relative Standard ◽

Nitrogen Doped Carbon

In this work, fluorescent nitrogen-doped carbon dots (N-CDs) were pyrolysis synthesized using edetic acid and acrylamide as precursors without further surface modication. The as-prepared N-CDs were mono-dispersed spherical nanoparticles with an average diameter of 3.25 nm. The blue fluorescence emission was dependent of the excitation wavelengths, releasing stable and strong blue fluorescence under the maximum excitation wavelength. More strikingly, after adding picric acid (PA), the fluorescence of N-CDs aqueous solution gave rise to the obviously fluorescence quenching due to the inner filter effect. Under the optimum conditions, the fluorescence probe can be used for the selective detection of PA with a wide linear relationship in the range of 0.01–32 μM and the detection as low as 0.046 μM. Depending on the fluorescence quenching phenomenon, the resultant fluorescent probe for accurate and selective monitor of PA in Fenhe river samples was explored. The recoveries fell in the range of 97.13%–106.21% and the relative standard deviation was below 3% with satisfactory results.

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Synthesis, Characterization and in vitro Biological Evaluation of a New Schiff Base Derived from Drug and its Complexes with Transition Metal Ions

Revista de Chimie ◽

10.37358/rc.18.7.6393 ◽

2018 ◽

Vol 69 (7) ◽

pp. 1678-1681

Author(s):

Amina Mumtaz ◽

Tariq Mahmud ◽

M. R. J. Elsegood ◽

G. W. Weaver

Keyword(s):

Schiff Base ◽

Transition Metal ◽

Metal Ions ◽

Metal Complexes ◽

Transition Metal Complexes ◽

Free Ligand ◽

Transition Metal Ions ◽

Biological Evaluation ◽

Pyridoxal Hydrochloride

New series of copper (II), cobalt (II), zinc (II), nickel (II), manganese (II), iron (II) complexes of a novel Schiff base were prepared by the condensation of sulphadizine and pyridoxal hydrochloride. The ligand and metal complexes were characterized by utilizing different instrumental procedures like microanalysis, thermogravimetric examination and spectroscopy. The integrated ligand and transition metal complexes were screened against various bacteria and fungus. The studies demonstrated the enhanced activity of metal complexes against reported microbes when compared with free ligand.

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Efficient Preconcentration of Cu2+, Zn2+ and Fe3+ with an Agarose-Schiff Base Sorbent

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20070908 ◽

2007 ◽

Vol 72 (7) ◽

pp. 908-916 ◽

Cited By ~ 3

Author(s):

Payman Hashemi ◽

Hatam Hassanvand ◽

Hossain Naeimi

Keyword(s):

Schiff Base ◽

Metal Ions ◽

Metal Ion ◽

Good Accuracy ◽

Kinetic Studies ◽

Sample Volume ◽

Effects Of Ph ◽

Glass Column ◽

High Concentrations ◽

Ph Range

Sorption and preconcentration of Cu2+, Zn2+ and Fe3+ on a salen-type Schiff base, 2,2'- [ethane-1,2-diylbis(nitrilomethylidyne)]bis(2-methylphenol), chemically immobilized on a highly crosslinked agarose support, were studied. Kinetic studies showed higher sorption rates of Cu2+ and Fe3+ in comparison with Zn2+. Half-times (t1/2) of 31, 106 and 58 s were obtained for sorption of Cu2+, Zn2+ and Fe3+ by the sorbent, respectively. Effects of pH, eluent concentration and volume, ionic strength, buffer concentration, sample volume and interferences on the recovery of the metal ions were investigated. A 5-ml portion of 0.4 M HCl solution was sufficient for quantitative elution of the metal ions from 0.5 ml of the sorbent packed in a 6.5 mm i.d. glass column. Quantitative recoveries were obtained in a pH range 5.5-6.5 for all the analytes. The volumes to be concentrated exceeding 500 ml, ionic strengths as high as 0.5 mol l-1, and acetate buffer concentrations up to 0.3 mol l-1 for Zn2+ and 0.4 mol l-1 for Cu2+ and Fe3+ did not have any significant effect on the recoveries. The system tolerated relatively high concentrations of diverse ions. Preconcentration factors up to 100 and detection limits of 0.31, 0.16 and 1.73 μg l-1 were obtained for Cu2+, Zn2+ and Fe3+, respectively, for their determination by a flame AAS instrument. The method was successfully applied to the metal ion determinations in several river water samples with good accuracy.

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Utilization and simulation of innovative new binuclear Co(ii), Ni(ii), Cu(ii), and Zn(ii) diimine Schiff base complexes in sterilization and coronavirus resistance (Covid-19)

Open Chemistry ◽

10.1515/chem-2021-0068 ◽

2021 ◽

Vol 19 (1) ◽

pp. 772-784

Author(s):

Moamen S. Refat ◽

Ahmed Gaber ◽

Walaa F. Alsanie ◽

Mohamed I. Kobeasy ◽

Rozan Zakaria ◽

...

Keyword(s):

Schiff Base ◽

Molecular Docking ◽

Metal Ions ◽

Free Ligand ◽

Schiff Base Complexes ◽

Hydroxyl Groups ◽

Binuclear Complexes ◽

Central Metal ◽

H Nmr ◽

Biological Studies

Abstract This article aimed at the synthesis and molecular docking assessment of new diimine Schiff base ligand, namely 2-((E)-(2-((Z)-2-(4-chlorophenyl)-2-hydroxyvinyl)hydrazono) methyl)-6-methoxyphenol (methoxy-diim), via the condensation of 1-(4-chloro-phenyl)-2-hydrazino-ethenol compound with 2-((E)-(2-((Z)-2-(4-chlorophenyl)-2-hydroxy vinyl) hydrazono)methyl)-6-methoxyphenol in acetic acid as well as the preparation of new binuclear complexes of Co(ii), Ni(ii), Cu(ii), and Zn(ii). The following synthesized complexes were prepared in a ratio of 2:1 (metal/ligand). The 1H-NMR, UV-Vis, and FTIR spectroscopic data; molar conductivity measurements; and microanalytical, XRD, TGA/DTG, and biological studies were carried out to determine the molecular structure of these complexes. According to the spectroscopic analysis, the two central metal ions were coordinated with the diamine ligand via the nitrogen of the hydrazine and oxygen of the hydroxyl groups for the first metal ions and via the nitrogen of the hydrazine and oxygen of the phenol group for the second metal ions. Molecular docking for the free ligand was carried out against the breast cancer 3hb5-oxidoreductase and the 4o1v-protein binding kidney cancer and COVID-19 protease, and good results were obtained.

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