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1.
ABSTRACT

In this work, a new turn-on fluorescent probe 1 for Hg2+ ions detection based on rhodamine B spirolactam was reported. Among tested metal ions, probe 1 shows high selectivity towards Hg2+ in the the mixture solution of methanol and 0.02 M HEPES buffer (V/V = 9:1, pH = 7.2). No absorption and emission band of probe 1 was observed in the range from 450 to 700 nm. While only addition of Hg2+ to probe 1 could lead to appearance of a new absorption band centered at 553 nm and a fluorescence emission band around 577 nm upon excitation at 520 nm. Moreover, it exhibits excellent linear relationship (R2 = 0.9993) between fluorescence intensity at 577 nm and the concentration of Hg2+ from 1.6 to 32 μM. The sensing mechanism was proven to be spirolactam ring open induced by Hg2+ through 1H NMR, MS, absorption and fluorescence spectra. In addition, probe 1 could detect Hg2+ in real water samples and on filter paper, which demonstrates its application in environment science.  相似文献   

2.
We introduce a new rhodamine-based fluorescent chemosensor, FD8 which exhibits a distinct two-photon excited fluorescence (TPEF) on/off characteristic upon binding Cr3+ ions. By coordination with metal cation, conformation of FD8 changes from spirocyclic to open-ring, resulting in remarkable enhancement of absorption and fluorescence both in one- and two-photon excitations. As a result, a 29-fold enhancement of two-photon excited fluorescent intensity was observed when 10 eq. Cr3+ was added to the FD8 solution. The detection limit of Cr3+ cation concentration down to 1 μM (0.01 eq. of FD8) was achieved under our experimental condition. Besides the excitation within ultraviolet regime by fluorescence resonance energy transfer (FRET) mechanism, the TPEF on/off behavior further extends the excitation to near infrared regime (the biological optimal window of 700-1200 nm), and shows more effective sensitivity. The broad excitation wavelength, on/off fluorescence and high selectivity to Cr3+ enable FD8 to be a powerful Cr3+ cation sensor with potential application, especially in biological detection. To the best of our knowledge, this is the first report about two-photon fluorescent sensor for Cr3+ ions.  相似文献   

3.
A new pyrene-containing fluorescent sensor has been synthesized from 2,3,3-trimethylindolenine. Spectroscopic and photophysical properties of sensor are presented. The large change in fluorescence intensity (I/I0 = 0.13) at 381 nm and affinity to Hg2+ over other cations such as K+, Na+, Ca2+, Mg2+, Pb2+, and Cu2+ make this compound a useful chemosensor for Hg2+ detection in hydrophilic media. The sensor (6.0 × 10−6 M) displays significant fluorescence quenching upon addition of Hg2+ in pH 7.4 HEPES buffer without excimer formation. Job’s plot analysis shows the binding stoichiometry to be 2:1 (host/guest).  相似文献   

4.
A simple fluorescent probe, which contains rhodamine and aminoquinoline moieties, was designed and prepared for selective detection of Hg2+ in acetonitrile. RbQ exhibited high selectivity and sensitivity toward Hg2+ over other common metal ions. The recognition of RbQ toward Hg2+ can be detected by fluorescence spectra, absorption spectra, and even by naked eyes. The binding ratio of the RbQ–Hg2+ complex was found to be 1:1 according to Job plot experiment, and the limit of detection was 1.05×10−7 M. Moreover, the prepared complex RbQ–Zn2+ (RbQZ) could detect Hg2+ in a ratiometric way and showed lower limit of detection (2.95×10−8 M) than RbQ in the same condition. Finally, we also demonstrated that the aminoquinoline–zinc complex could be served as a new and effective FRET donor for rhodamine derivatives.  相似文献   

5.
An anthracene-oxyquinoline dyad (HQ-AN) is synthesized which acts as a selective fluorescent reporter for Hg(II) with a detection limit of 3.2 × 10−6 M in acetonitrile-water system. The phenomenon of unfolding of HQ-AN from its initial folded conformation in acetonitrile-water system, selectively in the presence of Hg(II) is indicated from spectrofluorometric studies. The sensing event is monitored by the marked change in fluorescence emission occurring due to quenching of the excimer and retaining of the monomer emission of the two anthracene units in HQ-AN.  相似文献   

6.
A novel fluorometric sensor bearing three dansyl moieties based on tris[2-(2-aminoethylthio)ethyl]amine was prepared by a simple approach using a conventional two-step synthesis. The sensor exhibits highly Hg2+-selective ON-OFF fluorescence quenching behavior in aqueous acetonitrile solutions and is shown to discriminate various competing metal ions, particularly Cu2+, Ag+, and Pb2+ as well as Ca2+, Cd2+, Co2+, Fe3+, Mn2+, Na+, Ni2+, and Zn2+, with a detection limit of 1.15 × 10−7 M or 23 ppb.  相似文献   

7.
Honglei Mu 《Tetrahedron letters》2007,48(31):5525-5529
A novel two-channel metal ion sensor has been synthesized from macrocyclic dioxotetraamine and 1,8-naphthalimide derivative. The metal ion-selective signaling behaviors of the sensor were investigated. The sensor presented the selective coloration for Cu2+ and Hg2+ that can be detected by the naked-eye, respectively. Besides, the addition of Cu2+ and Hg2+ quenched the fluorescence of 1 obviously and the detection limit was found to be 3 × 10−7 M for Cu2+ and 7 × 10−7 M for Hg2+. This sensor can be utilized for the visual and spectroscopic detection of Cu2+ or Hg2+ in the presence of the other competing metal ions.  相似文献   

8.
In the present work, a green synthetic method for producing nitrogen-doped carbon dots (NCDs) by using ammonium citrate and urea is introduced. The obtained NCDs were characterised by transmission electron microscopy, Fourier transform infrared spectra, UV–vis absorption and fluorescence spectra. The results showed that the prepared NCDs were spherical with a size of about 3.5 nm, emitting strong and stable blue fluorescence when excited at 352 nm. It was noting that the NCDs enable sensitive and selective determination of Hg2+ in tap water with a linear range of 0.01–5 mg L?1 based on a possible charge transfer process. The detection limit was 9.4 µg L?1.  相似文献   

9.
Abstract

A fluorescent sensor TPE-TSC with aggregation induced emission (AIE) characteristic is synthesized for detecting Hg2+ by attaching thiosemicarbazide (TSC) unit into tetraphenylethylene (TPE) group. TPE-TSC exhibits intense green emission in DMSO/H2O (V:V?=?1:9) solution with the formation of the aggregation. TPE-TSC shows outstanding fluorescence quenching toward Hg2+ over other metal ions due to the formation of complex TPE-TSC/Hg2+ with a 2:1 binding ratio. The detection limit of TPE-TSC for Hg2+ is 1?×?10?5 mol·L?1.  相似文献   

10.
A ratiometric, near-infrared, and fully water-soluble probe, a phenoxazinium-based chemosensor bearing an anilino thiaazacrown, was successfully synthesized and characterized. The use of this probe for the selective ratiometric detection of Hg2+ in pure water is reported. The probe shows good selectivity for Hg2+, and a large blue shift (75 nm) of the complex’s absorption maximum was observed.  相似文献   

11.
A novel single-armed Salamo-type bisoximes (H4L) has been designed and synthesised. An obvious colour change from yellow (H4L) to pale pink (HL-Pb2+) which can be visually observed by the naked eye in visible light. H4L can act as a fluorescent sensor for ratiometric recognition of Zn2+ with high selectivity and sensitivity. Crystallographic data of the [Cu(HL)(μ-OAc)Cu] reveals that the two Cu2+ ions are both penta-coordinated with square pyramidal geometries, and forms a 2D supramolecular plane structure by hydrogen bonding interactions.  相似文献   

12.
A simple epoxy-based oligomer 1 containing naphthylazobenzene-appended dithia-aza moieties was prepared. In UV–vis measurements, the proposed oligomer showed the ion-sensing ability to Hg2+ and Cu2+ ions. The discrimination between two differently responding Hg2+ and Cu2+ ions was also realised from ‘ON–OFF’ type fluorescence responses of 1.  相似文献   

13.
A new fluorescein-based chemodosimeter (II) for Hg2+ ion was designed and synthesized, and it displayed excellent selective and sensitive toward Hg2+ ion over other commonly metal ions in aqueous media. II was a colorless, non-fluorescent compound. Upon addition of Hg2+ to the solution of II, the thiosemicarbazide moiety of II would undergo an irreversible desulfurization reaction to form its corresponding oxadiazole (IV), a colorful and fluorescent product. During this process, the spirocyclic ring of II was opened, causing instantaneous development of visible color and strong fluorescence emission in the range of 500-600 nm. Based on the above mechanism, a fluorogenic Hg2+-selective chemodosimeter was developed. The fluorescence increase is linearly with Hg2+ concentration up to 1.0 μmol L−1 with a detection limit of 8.5 × 10−10 mol L−1 (3σ). Compared with the rhodamine-type chemodosimeter, II is more stable in aqueous media and exhibits higher sensitivity toward Hg2+. The findings suggest that II will serve as a practical chemodosimeter for rapid detection of Hg2+ concentrations in realistic media.  相似文献   

14.
Naphthalimide derivative (compound 1) containing hydrophilic hexanoic acid group was synthesized and used to recognize Hg2+ in aqueous solution. The fluorescence enhancement of 1 is attributed to the formation of a complex between 1 and Hg2+ by 1:1 complex ratio (K = 2.08 × 105), which has been utilized as the basis of fabrication of the Hg2+-sensitive fluorescent chemosensor. The comparison of this method with some other fluorescence methods for the determination of Hg2+ indicated that the method can be applied in aqueous solution rather than organic solution. The analytical performance characteristics of the proposed Hg2+-sensitive chemosensor were investigated. The chemosensor can be applied to the quantification of Hg2+ with a linear range covering from 2.57 × 10−7 to 9.27 × 10−5 M and a detection limit of 4.93 × 10−8 M. The experiment results show that the response behavior of 1 toward Hg2+ is pH independent in medium condition (pH 4.0–8.0). Most importantly, the fluorescence changes of the chemosensor are remarkably specific for Hg2+ in the presence of other metal ions, which meet the selective requirements for practical application. Moreover, the response of the chemosensor toward Hg2+ is fast (response time less than 1 min). In addition, the chemosensor has been used for determination of Hg2+ in hair samples with satisfactory results, which further demonstrates its value of practical applications.  相似文献   

15.
A label-free supersandwich fluorescent assay was demonstrated for the first time by taking Hg2+ as a detection candidate. The principle of the proposed supersandwich fluorescent platform is based on the formation of supersandwich structure by T-Hg2+-T coordination and the fluorescence enhancement of the intercalated Genefinder (GF) in double strand DNA (dsDNA). Such supersandwich fluorescent DNA sensor exhibits a linear range of 10–300 nM for the detection of Hg2+, with a detection limit of 2.5 nM on the basis of the 3σ/slope (σ represents the standard deviation of the blank samples), which is well below the permit of the U.S. Environmental Protection Agency (<10 nM). The detection can be fulfilled in less than 10 min. The proposed mix-and-detect fluorescent platform exhibits excellent sensitivity, selectivity, and convenient manipulation. The assay was successfully used to detect Hg2+ in the lake water samples, which suggested its potential in practical samples.  相似文献   

16.
Fluorescent Red GK, a commercially available coumarin-based dye, was developed as a “turn-off” fluorescent probe for detection of Cu2+ in aqueous solution. It exhibited high selectivity and sensitivity at room temperature. Upon addition of Cu2+, the strong fluorescence of Fluorescent Red GK was severely quenched and its color changed from orange to colorless under illumination with a UV lamp; the color of the solution also changed from pink to colorless. So, it can be used as a specific colorimetric and fluorescent probe for Cu2+ with a detection limit as low as 0.0634?μM.  相似文献   

17.
The heavy metal mercury (Hg) is a threat to the health of people and wildlife in many environments. Among various chemical forms, Hg2+ salts are usually more toxic than their counterparts because of their greater solubility in water; thus, they are more readily absorbed from the gastrointestinal tract into circulation. Therefore, new chemical receptors for detecting Hg2+ ions in circulation are needed. In this study, we developed a rhodamine-based turn-on fluorescence probe to monitor Hg2+ in aqueous solution and in blood of mice with toxicosis. The chemodosimeter responds to Hg2+ ions stoichiometrically, rapidly, and irreversibly at room temperature as a result of a chemical reaction that produces strongly fluorescent oxadiazole. The new fluorescent probe shows good fluorescence response, with high sensitivity and selectivity, toward Hg2+ ions in aqueous solution and in blood from mice with toxicosis and facilitates the naked-eye detection of Hg2+ ions.  相似文献   

18.
A simple but highly selective coumarin-based fluorescence probe 1, 8-(1,3-dithiane)-7-hydroxycoumarin was designed and synthesized for both the ratiometric detection of Hg2+ and the on–off response to pH change in aqueous solution. The sensor detected Hg2+ selectively via Hg2+-promoted thioacetal deprotection reaction within five minutes and reflected pH in the range from 7.8 to 11.9 as a result of the equilibrium between weak-fluorescent acid form and strong-fluorescent base form. In addition, the probe has an excellent selectivity towards Hg2+ over other competitive metal ions for biomedical and environmental applications. The sensing behavior of our probe was studied by UV–visible absorption spectra and fluorescence spectra.  相似文献   

19.
A new receptor 3-((2-(1H-benzo[d]imidazol-2-yl)phenylimino)methyl)benzene-1,2-diol (1) was synthesised and developed as a highly selective fluorescent chemosensor for the detection of Hg2+ in semi-aqueous media. The fluorescence of receptor 1 was dramatically and selectively quenched on complexation with Hg2+ ion with the detection limit down to 0.20 μM. The developed sensor was successfully applied for the determination of Hg2+ content in water samples. Density Functional Theory (DFT) calculations were performed to study the mechanistic behaviour behind the binding of Hg2+ with receptor 1.  相似文献   

20.
A novel rhodamine-based chemosensor (R) was designed and synthesised for selective recognition of Hg2+ ion in real water samples collected from different places. The chemosensor was prepared in green condition with high yield. The selectivity of R was examined with various metal ions, among which only Hg2+ was identified selectively with offon mechanism along with enhancement of fluorescence. Metal ions recognition has been carried out using UV–vis and fluorescence studies taking µM concentration of chemosensor R in HEPES buffer. The detection limit of R was calculated and found to be 4.4 × 10–9 M. Quantum chemical (DFT) calculation was carried out in order to acquire knowledge about the stability of R in presence of Hg2+ ions. Cell viability and fluorescence microscopic experiments showed R as cytocompatible and can be used as a fluorescent probe for detecting Hg2+ in living cells.  相似文献   

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