Development Of Fluorescent Chemosensors Research Articles

Recent Advances in Graphitic Carbon Nitrides (g‐C3N4) as Photoluminescence Sensing Probe: A Review

AbstractAmong the wide range of chemosensors, the development of fluorescent chemosensors has shown continued interest in the domains of chemistry, materials, biology, and ecology due to their simple operation, low cost, high sensitivity, specificity, live observation, and short response time. As a metal‐free and fluorescent chemosensor, graphitic carbon nitride (g‐C3N4) has emerged as a new research hotspot and received widespread interdisciplinary attention which is attributable to its favorable electrical band structure, high physicochemical stability, and “earth‐abundant” nature. This review summarizes the structure, synthetic methods, and various techniques for the modification of g‐C3N4. This review also covers the development of g‐C3N4 nanomaterials‐based sensors and their potential applications in a variety of fields. Furthermore, the comparative performance of various sensors, existing obstacles, and perspectives of g‐C3N4‐based nanomaterials are also outlined in detail.

Editorial: Organic Fluorescent Materials as Chemical Sensors

The last two decades have witnessed a significant development of fluorescent chemosensors with high sensitivity and selectivity, fast response and in situ detection [...]

Review on g-C3N4 Based Fluorescence Chemical Sensor for Detection of Heavy Metal Ions

Recently, among many kinds of chemo sensors, the development of fluorescent chemo sensors for the sensing of environmentally toxic heavy metal ions has drawn continuous interest in fields of chemistry, materials, biological and environmental sciences due to the low cost, simple operation, high sensitivity and specificity, real-time monitoring and short response time. Upon interactions with the metal ions, the fluorescence intensity and/or fluorescence band shift of the chemosensory change and the metal ions may be detected qualitatively and quantitatively. Many methods employ techniques related to metal ion sensing. The quenching photoluminescence of carbon-based nanodots has been focused on monitoring metal ions. The employ g-C3N4 as fluorescence chemical sensors for heavy metal ions detection has caused increased attention largely due to its fluorescent property. Several groups have demonstrated the use of different g-C3N4 nanostructures for fluorescent metal ions sensing. Considering the properties of present chromogenic/fluorescent receptors, it seems that nanostructured g-C3N4 would be a promising alternative. The electronic structure of g-C3N4 is adjustable by coupling events of protons or metals to the surface. Therefore, the strong coordination of the nitrogen sites of g-C3N4 to metal ions, causes fluorescence quenching via photoinduced electron transfer and static quenching leading to the qualitative and quantitative detection of metal ions. It has been brought into some brilliant applications, Specially for detection of Cu2+, Fe3+, Hg+2 and Ag+ has been developed based on the fluorescence quenching because of the photoinduced electron transfer (PET) from g-C3N4 to metal ion and also it is best alternate than other material for detection of metal ion because of its low-cost, good biocompatibility, high quantum yield, excellent stability and non-toxicity.

Coumarin-Based Small-Molecule Fluorescent Chemosensors.

Coumarins are a very large family of compounds containing the unique 2H-chromen-2-one motif, as it is known according to IUPAC nomenclature. Coumarin derivatives are widely found in nature, especially in plants and are constituents of several essential oils. Up to now, thousands of coumarin derivatives have been isolated from nature or produced by chemists. More recently, the coumarin platform has been widely adopted in the design of small-molecule fluorescent chemosensors because of its excellent biocompatibility, strong and stable fluorescence emission, and good structural flexibility. This scaffold has found wide applications in the development of fluorescent chemosensors in the fields of molecular recognition, molecular imaging, bioorganic chemistry, analytical chemistry, materials chemistry, as well as in the biology and medical science communities. This review focuses on the important progress of coumarin-based small-molecule fluorescent chemosensors during the period of 2012-2018. This comprehensive and critical review may facilitate the development of more powerful fluorescent chemosensors for broad and exciting applications in the future.

On the use of mixed thia/aza macrocycles in the development of fluorescent chemosensors for toxic heavy metals and fluorescent materials

The main results from the work of the authors, concerning the use of mixed thia/aza medium sized macrocycles for the development of optically selective fluorescent chemosensors for toxic heavy metals, and luminescent gold(I) complexes will be discussed. Particular attention will be paid to underline both the role played by these macrocyclic ligands in determining the properties of the systems developed and the structure/function relationships observed.

"Turn-on" type colorimetric/fluorimetric probe for selective detection of Cu2+at neutral pH condition

The design and development of fluorescent chemosensors have recently been intensively explored for sensitive and specific detection of environmentally and biologically relevant metal ions in aqueous solution and living cells. Herein, we report the photophysical results of rhodamine B based fluorogenic and chromogenic receptor for selective copper detection in the complete organic or mixed aqueous-organic media at neutral pH under ambient condition. The ligand exhibited the remarkable increment in the fluorescence emission and UV-visible absorption signal intensities at 587 and 547 nm, respectively, on induction of copper ion while the ligand solution remain completely silent on addition of varieties of other metal ions.

A highly selective dual-channel Cu2+ and Al3+ chemodosimeter in aqueous systems: Sensing in living cells and microfluidic flows

The design and development of fluorescent chemosensors have recently been the focus of considerable attention for the sensitive and specific detection of environmentally and biologically relevant metal ions in aqueous solutions and in living cells. Herein, we report photophysical results for a 1H-pyrrole-2-carboxaldehyde-substituted rhodamine 6G derivative (RCS) that possesses specific binding affinity toward Al3+ and Cu2+ at micromolar concentration levels. In an N,N-dimethylformamide (DMF) and water (v/v=2/8) medium, the RCS chemosensor exhibits a substantially enhanced absorbance intensity at 532nm and a color change from colorless to pink for Cu2+; it also exhibits significant “off–on” fluorescence at 557nm, accompanied by a color change from colorless to fluorescent-yellow upon binding to Al3+. The RCS sensor exhibits extremely high fluorescence enhancement upon complexation with Al3+, and it can be used as a “naked eye” sensor. Through fluorescence titration at 557nm, we confirmed that RCS exhibits a fluorescence response with a remarkable enhancement in emission intensity resulting from the complexation between RCS and Al3+, whereas no emission appeared in the case of competitive metal ions (Cu2+, Al3+, Li+, Na+, K+, Cs+, Mg2+, Ca2+, Fe2+, Co2+, Ag+, Zn2+, Cd2+, Hg2+ and Pb2+) in a DMF and water (v/v=2/8) solution. The reversible ring-opening mechanism of the rhodamine spirolactam induced by Al3+/Cu2+ binding and the 1:1 stoichiometric structure between RCS and Al3+ were adequately supported by Job-plot evaluation, optical titration and FT-IR analysis. The lowest detection limit for Al3+ is 3.20×106M−1 in a DMF and water (v/v=2/8) solution. Al3+-induced chelation-enhanced fluorescence (CHEF) is associated with spirolactam ring opening of the rhodamine unit. Finally, RCS was successfully applied for the bio-imaging of Al3+ in living HeLa cells and for fluorescence imaging of a microfluidic system.

The smart 2-(2-fluorobenzoyl)-N-(2-methoxyphenyl)hydrazinecarbothioamide functionalized as Ni(II) sensor in micromolar concentration level and its application in live cell imaging.

In recent years, fluorescent probes for the detection of environmentally and biologically important metal cations have received extensive attention for designing and development of fluorescent chemosensors. Herein, we report the photophysical results of 2-(2-fluorobenzoyl)-N-(2-methoxyphenyl) hydrazinecarbothioamide (4) functionalized as Ni (II) sensor in micromolar concentration level. Through fluorescence titration at 488 nm, we were confirmed that ligand 4 showed the remarkable emission by complexation between 4 and Ni (II) while it appeared no emission in case of the competitive ions (Cr(3+), Fe(2+), Co(2+), Ba(2+), Cu(2+), Ca(2+), Na(+), K(+), Cu(+), Cs(+)). Furthermore, ligand 4 exhibited no toxicity with precise cell permeability toward normal living cells using L929 cell lines in bio imaging experiment investigated through confocal fluorescence microscope. The non-toxic behavior of ligand 4 (assessed by MTT assay) and its ability to track the Ni(2+) in living cells suggest its possibility to use in biological system as nickel sensor.

Facile synthesis, cytotoxicity and bioimaging of Fe3+ selective fluorescent chemosensor

The designing and development of fluorescent chemosensors have recently been intensively explored for sensitive and specific detection of environmentally and biologically relevant metal ions in aqueous solution and living cells. Herein, we report the photophysical results of alanine substituted rhodamine B derivative 3 having specific binding affinity toward Fe3+ with micro molar concentration level. Through fluorescence titration at 599nm, we were confirmed that ligand 3 exhibited ratiometric fluorescence response with remarkable enhancement in emission intensity by complexation between 3 and Fe3+ while it appeared no emission in case of the competitive ions (Sc3+, Yb3+, In3+, Ce3+, Sm3+, Cr3+, Sn2+, Pb2+, Ni2+, Co2+, Cu2+, Ba2+, Ca2+, Mg2+, Ag+, Cs+, Cu+, K+) in aqueous/methanol (60:40, v/v) at neutral pH. However, the fluorescence as well as colorimetric response of ligand–iron complex solution was quenched by addition of KCN which snatches the Fe3+ from complex and turn off the sensor confirming the recognition process was reversible. Furthermore, bioimaging studies against L-929 cells (mouse fibroblast cells) and BHK-21 (hamster kidney fibroblast), through confocal fluorescence microscopic experiment indicated that ligand showed good permeability and minimum toxicity against the tested cell lines.

Exploiting the versatile assembly of arylpyridine fluorophores for wavelength tuning and SAR.

[reaction: see text] The facile modular assembly of polyarylpyridine fluorophores provides two important advantages in the development of fluorescent chemosensors: it allows rapid dissection of the structural requirements for fluorescent chemosensing and it allows dramatic tuning of emission wavelength by changes in a substituent remote from the binding site.