Ratiometric Fluorescent Chemodosimeter Research Articles

Swift and quantitative naked-eye detection of cyanide: A dual-mode approach using an ICT-based colorimetric and ratiometric fluorescent chemodosimeter

A chemodosimeter (1) based on dicyanovinyl with a strong intramolecular charge transfer (ICT) mechanism has been devised for the selective and sensitive detection of cyanide (CN−) in a tetrahydrofuran aqueous solution. In polar solvents, chemodosimeter 1 exhibits robust ICT-induced emission; however, in the solid state, its fluorescence weakens owing to the formation of molecular aggregates prompted by intermolecular π–π interactions. The colorimetric and ratiometric fluorescent changes observed in the chemodosimeter upon exposure to CN− result from the incorporation of CN− at the β-conjugated site of the dicyanovinyl moiety of chemodosimeter 1, effectively hindering the ICT process. This alteration is supported by 1H NMR titration experiments and density functional theory calculations, which corroborate the cyanide-induced ICT on–off switching mechanism. The detection limit of chemodosimeter 1 (5.8 × 10−7 M) for CN− falls below the maximum allowable level of cyanide in drinking water (1.9 × 10−6 M), as established by the World Health Organization. Test strips utilizing chemodosimeter 1 offer a potential solution for swift and quantitative naked-eye detection of CN− in real-time scenarios. Moreover, chemodosimeter 1 was effectively employed for detecting cyanide in actual environmental water samples.

Colorimetric and ratiometric fluorescent chemodosimeter for the detection of hydrazine via the Ing-Manske reaction in solution as well as in the gaseous state: An experimental and computational investigation

A new and simple fluoranthene-phthalimide conjugate (FP) was synthesized, and employed as a highly efficient hydrazine chemodosimeter in organo-aqueous solution. Based on the Ing-Manske reaction, the chemodosimeter FP showed a fast colorimetric and ratiometric fluorescent response for hydrazine with high sensitivity and selectivity over other competing analytes. The chemodosimeters detection limit for N2H4 was estimated to be 4.27 µM. Theoretical calculations were also executed to validate the experimental findings. Furthermore, the test strips and cotton swab made from the chemodosimeter FP are capable of enabling the quick and easy detection of N2H4 solution and vapour, respectively.

A ratiometric fluorescent chemodosimeter based on a hydrolysis reaction for the superwide continuous range detection of water in MeOH, MeCN, and DMF

In this work, a novel Schiff base chemodosimeter (2) based on salicylaldehyde containing a cyano group (1) and trometamol was designed and synthesized, which has a large Stokes shift (>100 nm) and remarkable solvatochromism. Compound 2 could be utilized as a sensitive fluorescent probe that quantitatively detects the water content in MeOH, MeCN, and DMF in a superwide continuous range and with a low detection limit, accompanied by a fluorescence color change from blue to green. The response range was 0–80% v/v for MeOH, 0–98% v/v for MeCN, and 0–90% v/v for DMF, and the detection limits were 0.0621% v/v (MeOH), 0.0327% v/v (MeCN) and 0.0910% v/v (DMF), respectively. Meanwhile, UV–Vis, IR, 1H NMR, and MS characterization methods were used to investigate the mechanism. The results showed that water induced the breaking of the CN bond of 2 and the structural transition between alcohol and ketone of 1. In addition, 2 was successfully loaded onto the test paper for the detection of water in the solid phase.

Ratiometric fluorescence chemodosimeter for hydrazine in aqueous solution and gas phase based on Quinoline-Malononitrile

The widespread use of Hydrazine (N2H4) in many areas of the chemical industry, brings potential risks to human health and environmental pollution. To detect N2H4 effectively, a simple ratio fluorescence probe (QMM), designed and synthesized through Vilsmeier reaction and Knoevenagel reaction, was prepared for the specific response of N2H4 based on the irreversible chemical reaction. The ratiometric fluorescence chemodosimeter displayed a response for hydrazine with high selectivity, sensitivity and anti-interference ability. The measured detection limit is 38.30 nm (0.122 ppb), which is far lower than the maximum allowable level of the U.S. Environmental Protection Agency (10 ppb). Moreover, test paper and TLC plates loading QMM had been made, which could be utilized to detect hydrazine both in aqueous solution samples and in gas phase samples. Thus QMM could serve as an easily manufactured, low-cost, efficient and portable solid-state optical probe to detect hydrazine in field measurements.

Ratiometric fluorescent detection of Hg(II) by amino-acid based fluorescent chemodosimeter using irreversible reaction of phenylboronic acid with mercury species

Boronic acids have been widely employed as important intermediates for various organic syntheses and reversible receptors for glucose and carbohydrates. We developed a new ratiometric fluorescent chemodosimeter for Hg2+ based on an irreversible reaction of phenylboronic acid with Hg2+. The fluorescent chemodosimeter (1) bearing a phenylboronic acid as a reaction site showed a selective and sensitive ratiometric signal behavior to low concentrations of Hg2+ ions in aqueous solutions containing 1% CH3CN. The ratiometric signaling was not considerably inhibited by coexisting other metal ions. The detection limit was measured to be 7.0 nM for Hg2+ based on the linear ratiometric signal to the nanomolar concentration (0–500 nM) of mercury ions. The signal mechanism study revealed that 1 reacted with Hg2+, providing covalent product of mercury ion (3) by replacement reaction of the boronic group of 1 with Hg2+, which exhibited fluorescent spectrum changes. The reaction kinetic study suggested that the rate law of the reaction is 1st order in Hg2+ and 1st order in the probe, and 2nd order overall. Real world application of the fluorescent chemodosimeter was demonstrated by quantification of Hg2+ ions in groundwater and tap water samples spiked with known amounts of Hg2+ ions.

A new ratiometric fluorescent chemodosimeter for sensing of Hg2+ in water using irreversible reaction of arylboronic acid with Hg2+

We synthesized a highly selective ratiometric fluorescent chemodosimeter (1) for Hg2+ on the basis of the displacement reaction of phenylboronic acid with Hg2+ ions. The fluorescent chemodosimeter sensitively detected Hg2+ ions by two emission maxima with a 100 nm different wavelength. 1 exhibited remarkable detection property for Hg2+ such as high selectivity, high sensitivity, large fluorescent signal changes, ratiometric detection, and well-operation in aqueous solutions. Especially, the coexisting other metal ions did not interfere considerably with the ratiometric detection of Hg2+. The binding mode study indicated that the displacement reaction of 1 with Hg2+ provided the covalent adduct (2) of mercury ion, which aggregated in aqueous solution, resulting in the large fluorescent signal changes. Utilizing the ratiometric chemodosimeter with the low detection limit (15.2 nM) for Hg2+, nanomolar concentrations (0∼350 nM) of Hg2+ was successfully detected in aqueous solutions. 1 provided a ratiometric fluorescent detection method to quantify low levels of Hg2+ in groundwater and tap water samples.

Red‐Emitting Ratiometric Fluorescence Chemodosimeter for the Discriminative Detection of Aromatic and Aliphatic Amines

AbstractA NIR‐emitting fluorescent probe using phenothiazine and 1,3‐dimethylbarbituric acid (PMB) connected through methylene bridge was developed in a two‐step simple chemical reaction. The fluorescent probes were highly reactive towards various primary amines and the reaction was accompanied by the changes in the optical and fluorescent properties of the PMB characteristic to the amine and thereby can have the potential to be used as a sensor for amines. In addition to the ratiometric changes in the fluorescence intensity corresponding to the PMB before and after reaction with an amine, the emission spectral maximum is specific to the analyte. For, example 1,4‐diaminobenzene, 4‐methoxyaniline, aniline, hydrazine, ethylamine, ethylenediamine respectively shows the maximum at 532, 546, 555, 484, 497, and 488 nm and this unique feature originated due to the involvement of the analyte in the extended π‐conjugation with the probe. Sensor strips prepared using PMB coated filter paper were able to sense the volatile amine gases with shorter response time. Analysis of the strips using the CIELAB 1976 color coordinates provides different signals for hydrazine, aniline, propylamine, and ethylamine gases. The applicability of the sensor was further ascertained by monitoring the decomposition of skin used for leather processing and also proteins engineered with an amino‐functionalized unnatural amino acid.

A thiocoumarin-based colorimetric and ratiometric fluorescent probe for Hg2+ in aqueous solution and its application in live-cell imaging

A new intramolecular charge transfer (ICT) based colorimetric and ratiometric fluorescent chemodosimeter for the detection of Hg2+ has been rationally designed and developed.

A ratiometric fluorescence chemodosimeter for detecting Hg2+ in aqueous solutions and living cells

A new thiourea derivative (PT) bearing a water-soluble porphyrin fluorophore was synthesized and used as a highly sensitive and selective chemodosimeter for mercury ions (Hg2+) in aqueous solution. PT exhibits large ratiometric absorption and fluorescence emission variations upon exposure to various Hg2+ concentrations based on the Hg2+-promoted intramolecular cyclic guanylation of thiourea. This mechanism was verified via NMR, MS, and FT-IR spectral data. The chemodosimeter is highly selective for Hg2+ in the presence of alkali, alkaline earth, transition, and heavy metal ions in the physiological pH window with a detection limit of ppb level. The selectivity can also be visualized under UV light, whereby the red fluorescence of PT becomes orange only in the presence of Hg2+. The potential practical application of PT to detect Hg2+ on paper strips is also described. Finally, in living cells, it exhibits excellent membrane permeability and low toxicity and thus can be used for confocal fluorescence imaging of intracellular Hg2+.

A smart ratiometric red fluorescent chemodosimeter for fluoride based on anthraquinone nosylate

A smart ratiometric red fluorescent chemodosimeter (AH) has been explored for specific detection of F− with a lowest detection limit of 3.45 × 10−10 M. The sensing mechanism was worked out as fluoride-triggered deprotonation of imidazole accompanied by deprotection of the nosylate group.

A new dual-channel ratiometric fluorescent chemodosimeter for Cu2+ and its imaging in living cells

A new BODIPY derivative bearing hydrazone and hydrazide moieties was developed as an efficient dual-channel ratiometric fluorescence chemodosimeter 1 for Cu2+ in neutral aqueous medium via Cu2+-mediated hydrolysis of CN bond in hydrazone unit. Confocal microscopy experiments have demonstrated that chemodosimeter 1 could also be used in live cells for the fast detection of Cu2+.

A novel naphthalimide-rhodamine dye: Intramolecular fluorescence resonance energy transfer and ratiometric chemodosimeter for Hg2+ and Fe3+

A novel ratiometric fluorescent chemodosimeter REPN based on 1,8-naphthalimide-rhodamine was successfully synthesized. Two different strategies of fluorescence resonance energy transfer (FRET) and photo-induced electron transfer (PET) for ratiometric detection of Hg2+/Fe3+ were designed into one sensing system. REPN exhibits typical FRET signal from pyridine-naphthalimide moiety to rhodamine moiety which was induced by Hg2+ with a detection limit of 2.72 × 10−6 M in EtOH/PBS buffer (1:1, v/v, pH = 7.4) solution. However, the probe REPN performed ratiometric detection behavior via PET process combined with the classical ring-opening sensor system in the presence of Fe3+, the detection limit was 5.7 × 10−7 M. REPN emitted bright yellow fluorescence in solid state and the maximum emission wavelength was 538 nm. Besides, the silica nanoparticles loaded AIE dye REPN maintained and further reinforced the AIE effect with higher water solubility.

A new colorimetric and ratiometric chemodosimeter for mercury (II) based on triphenylamine and benzothiadiazolenovel

Abstract A new near-infrared colorimetric and ratiometric fluorescent chemodosimeter for Hg2+ detection was devised, with a donor-acceptor-donor (D-A-D) molecular configuration and containing a dithioacetal group served as a sensing unit, and with a large stokes shift over 160 nm. The oxidation reaction of Hg2+ broke the electron-donating interaction of dithioacetal moiety, and the obstruction in the intramolecular charge transfer (ICT) induced remarkable changes in the absorption and emission spectra. The sensor exhibited splendid selectivity and anti-interference performance towards Hg2+ over other cations (K+, Na+, Ag+, Fe2+, Co2+, Mn2+, Zn2+, Ca2+, Pb2+, Ni2+, Mg2+, Cu2+, Al3+, Fe3+). The mechanism was investigated by absorption and emission spectra together with 1H NMR titration.

Diketopyrrolopyrrole-based novel ratiometric fluorescent chemodosimeter for Hg2+ detection in aqueous solution and in living cells

A new ratiometric fluorescent chemodosimeter based on the skeleton of diketopyrrolopyrrole was rationally designed and synthesized, which presented high sensitivity, selectivity for Hg2+ over other metal ions in aqueous solution leading to further applications of cell imaging. Red shift of chemodosimeter on absorption and fluorescence spectra upon Hg2+ binding was observed, which changed linearly with increase of Hg2+. This phenomenon was a typical deprotection process of acetal groups which increased the conjunction of DPP core that were confirmed by DFT.

A new ratiometric fluorescent chemodosimeter based on an ICT modulation for the detection of Hg2+

We design and synthesize a new ratiometric fluorescent chemodosimeter (S1) for the selective and sensitive detection of Hg2+. Upon addition of Hg2+, the emission of the S1 exhibits a large bathochromic shift from 393 to 515nm (up to 122nm) which is ascribed to an intramolecular charge transfer process in the resultant. The Hg2+-induced dethioacetalization for sensing mechanism has been demonstrated by using high-performance liquid chromatography analysis of the sensing process. The interference experiments further demonstrate that S1 exhibits very high selectivity towards Hg2+ over other coexisting cations/anions. Subsequently, a good linearity of the concentrations of Hg2+ (0–15μM) vs the ratiometric signals (I515/I393) allows a fluorogenic method for the quantitative detection of Hg2+, with the limitation of detection determined to be 5.22×10−7M.

Benzoindolium-triarylborane conjugates: a ratiometric fluorescent chemodosimeter for the detection of cyanide ions in aqueous medium.

Based on benzo[e]indolium and dimesitylborylbenzaldehyde a new ratiometric fluorescent chemodosimeter, C41H43BIN (3) has been synthesized and characterized by (1)H, (13)C NMR spectroscopy, mass spectrometry and single crystal X-ray crystallography. Probe 3 was found to be highly selective and sensitive toward cyanide (CN(-)) ions in aqueous medium even in the presence of other competing anions like F(-), Cl(-), Br(-), I(-), H2PO4(-), HCO3(-) and AcO(-). The detection limit was calculated to be 7.1 × 10(-9) M, which is much lower than the maximum permissable concentration in drinking water (1.9 μM) set by the World Health Organization (WHO). In addition, the response time of the probe for CN(-) is less than 5 seconds. The mechanism is based on a nucleophilic addition reaction of cyanide ions at the polarized [>C[double bond, length as m-dash]N<](+) bond of the benzoindolium group thereby blocking the pi-conjugation between the benzoindolium and triarylborane moiety. This was further confirmed by (1)H NMR titration, ESI-MS studies and DFT calculations.

Single excited state intramolecular proton transfer (ESIPT) chemodosimeter based on rhodol for both Hg2+and OCl−: ratiometric detection with live-cell imaging

We have synthesised a ratiometric fluorescence chemodosimeter,STBR, for the detection of Hg2+and OCl−in one platform over other cations, anions and oxidants in aqueous solution.

Macrocyclization of N,N′-propylenebis(3-formyl-5-tert-butylsalicylaldimine): a ratiometric fluorescence chemodosimeter for ZnII

Side off compartmental ligandN,N′-propylenebis(3-formyl-5-tert-butylsalicylaldimine) is used as a ratiometric fluorescence chemodosimeter for the selective detection of ZnIIions.

Colorimetric and ratiometric fluorescent chemodosimeter for selective sensing of fluoride and cyanide ions: tuning selectivity in proton transfer and C–Si bond cleavage

An anthraimidazolyldione based colorimetric and ratiometric fluorescent chemodosimeter (LHSi) was designed and synthesized for fluoride and cyanide ion sensing.

A remarkable ratiometric fluorescent chemodosimeter for very rapid detection of hydrogen sulfide in the vapour phase and living cells

A ratiometric fluorescent probe having a fast response and a large Stokes shift detects SH−both in solid and vapour phases and this probe is used for fluorescence imaging of SH−in living cells.