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1.
Yu C  Chen L  Zhang J  Li J  Liu P  Wang W  Yan B 《Talanta》2011,85(3):1627-1633
A novel Cu2+-specific “off-on” fluorescent chemosensor of naphthalimide modified rhodamine B (naphthalimide modified rhodamine B chemosensor, NRC) was designed and synthesized, based on the equilibrium between the spirolactam (non-fluorescence) and the ring-opened amide (fluorescence). The chemosensor NRC showed high Cu2+-selective fluorescence enhancement over commonly coexistent metal ions or anions in neutral aqueous media. The limit of detection (LOD) based on 3 × δblank/k was obtained as low as 0.18 μM of Cu2+, as well as an excellent linearity of 0.05-4.5 μM (R = 0.999), indicating the chemosensor of high sensitivity and wide quantitation range. And also the coordination mode with 1:1 stoichiometry was proposed between NRC and Cu2+. In addition, the effects of pH, co-existing metal ions and anions, and the reversibility were investigated in detail. It was also demonstrated that the NRC could be used as an excellent “off-on” fluorescent chemosensor for the measurement of Cu2+ in living cells with satisfying results, which further displayed its valuable applications in biological systems.  相似文献   

2.
A chemosensor based upon the sugar-aza-crown ether 7 with one anthracenetriazolymethyl moiety was prepared and its fluoroionophoric properties toward transition metal ions were investigated. Chemosensor 7 exhibits highly selective recognition toward Cu2+ ion among a series of tested metal ions in MeOH solution. The association constant for 7∗Cu2+ in MeOH solution was calculated to be 2.5 × 104 M−1.  相似文献   

3.
A novel fluorescent chemosensor 1 with two anthraceneisoxazolymethyl groups at the lower rim of calix[4]arene has been synthesized, which revealed a dual emission (monomer and excimer) when excited at 375 nm. This chemosensor displayed a selective fluorescence quenching only with Cu2+ ion over all other metal ions examined. When Cu2+ ion was bound to 1, the fluorescence intensities of both monomer and excimer were quenched. Furthermore, the association constant for the 1:1 complex of 1·Cu2+ was determined to be (1.58 ± 0.03) × 104 M−1.  相似文献   

4.
New N-(pyrenylmethyl)naphtho-azacrown-5 (1) was synthesized as an ‘On-Off’ fluorescent chemosensor for Cu2+. Excited at 240 nm corresponding to the absorption of naphthalene unit (energy donor) of 1, emission at 380 nm from pyrene unit (energy acceptor) is observed, indicating that intramolecular fluorescence resonance energy transfer (FRET-On) occurs in 1. When Cu2+ is added to a solution of 1, however, the fluorescence of pyrene is strongly quenched (FRET-Off) whereas that of naphthalene group is revived. Such FRET ‘On-Off’ behavior of 1 is observed only in the case of Cu2+ binding, but not for other metal cations. The high selectivity of 1 toward Cu2+ can be potentially applied to a new kind of FRET-based chemosensor. The FRET On-Off behavior is supported by computational studies. The calculated molecular orbitals of HOMO and LUMOs suggest the excited-state interactions leading to FRET from naphthalene to pyrene in 1, but no electron density changes in 1·Cu2+ complex.  相似文献   

5.
A new multifunctional chemosensor 1 was synthesized and characterized by spectroscopic tools along with a single crystal X-ray crystallography. It can exhibit selective recognition responses toward Cu2+, Zn2+ and Al3+ in different solvent systems with bimodal methods (colorimetric and fluorescence). This sensor 1 detected Cu2+ ions through a distinct color change from colorless to yellow in aqueous solution. Interestingly, the receptor 1 was found to be reversible by EDTA. The detection limit (11 μM) of 1 for Cu2+ is much lower than WHO guideline (30 μM) in drinking water. In addition, the sensor 1 showed significant fluorescence enhancements in the presence of Zn2+ ion and Al3+ ion in two different organic solvents (DMF and MeCN), respectively. The binding modes of the three complexes were determined to be a 1:1 complexation stoichiometry through Job plot, ESI-mass spectrometry analysis, and 1H NMR titration.  相似文献   

6.
New squaraine-based chemosensors SQ1 and SQ2 functionalized with 2-picolyl units were first synthesized and used as highly selective and sensitive colorimetric and fluorometric dual-channel sensors for Cu2+-specific recognition in aqueous systems. Among a series of individual metal ions, only Cu2+ could result in dramatic color changes. We also evaluated their capability of biological applications and found that SQ2 could be successfully employed as a Cu2+-selective probe in the fluorescence imaging of living cells.  相似文献   

7.
Two 4,5-disubstituted-1,8-naphthalimide derivatives 1 and 2 were synthesized as ratiometric fluorescent and colorimetric sensors for Cu2+, respectively. In 100% aqueous solutions of 1, the presence of Cu2+ induces a strong and increasing fluorescent emission centered at 478 nm at the expense of the fluorescent emission of 1 centered at 534 nm. Compound 2 senses Cu2+ by means of a colorimetric (primrose yellow to pink) method with a thorough quench in emission attributed to the deprotonation of the secondary amine conjugated to the naphthalimide fluorophore. 1-Cu2+ and 2-Cu2+ sense cyanide in ratiometric way via colorimetric and fluorescent changes.  相似文献   

8.
A new pyrene derivative (1) containing a diaminomaleonitrile moiety exhibits high selectivity for Cu2+ detection. Significant fluorescence enhancement was observed with chemosensor 1 in the presence of Cu2+. However, the metal ions Ag+, Ca2+, Cd2+, Co2+, Fe2+, Fe3+, Hg2+, Mg2+, Mn2+, Ni2+, Pb2+, and Zn2+ produced only minor changes in fluorescence values for the system. The apparent association constant (Ka) of Cu2+ binding in chemosensor 1 was found to be 5.55×103 M−1. The maximum fluorescence enhancement caused by Cu2+ binding in chemosensor 1 was observed over the pH range 5-7.5.  相似文献   

9.
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   

10.
A new bisthiazole chemosensor (3) with phenolic substituents at the position 2 of the thiazole rings was prepared. The chemosensor 3 acts as a potential dual-function fluorescence chemosensor with Cu2+ and Zn2+ ions causing complete quenching and ratiometric change of fluorescence, respectively. The mechanism of fluorescence was based on the cation-induced inhibition of excited-state intramolecular proton transfer (ESIPT).  相似文献   

11.
Carbohydrate based fluorescent sensors S1 and S2 have been developed by fluorogenic dual click chemistry and are characterized by various spectroscopic techniques. Both the fluorescent probes displayed highly selective detection of Cu2+ ions by means of fluorescence quenching. The job plot experiment suggested 1:1 complexation of probes S1 and S2 with Cu2+ ions having detection limit of 6.99 μM and 7.30 μM, respectively. The binding constants for S1-Cu2+ and S2-Cu2+ complexation were evaluated to be 3.34 × 103 M−1 and 5.93 × 103 M−1, respectively.  相似文献   

12.
We report the synthesis of a self organizable and water dispersible bis PEGylated (bis polyethyleneglycolated) curcumin (1) using an efficient synthetic method. Compound 1 forms nanoparticles on the order of 90 nm in water. Even though it forms nanoparticles, compound 1 interacts strongly with metal ions, Al+3, Cu+2, and Hg+2. Fluorescence and absorption spectroscopic techniques were employed to investigate the metal interactions of these nanoparticles. Al+3 and Cu+2 ions interact with compound 1 leading to enhancement and dramatic quenching in the fluorescence of the latter in 100% water, respectively. Addition of Hg+2 ions to compound 1 in water produces a ratiometric change in the absorption spectra of the nanoparticles. Although PEGylated curcumin derivatives were reported in the past, there have been no reports on their self organization into nanoparticles and extensive studies on their metal interaction properties in 100% water using its fluorescence and absorption properties.  相似文献   

13.
A coumarine–imino–C2-glucosyl conjugate (L) was synthesized and characterized. The conjugate L is found to recognize Cu2+ in aqueous HEPES buffer by exhibiting a 95% fluorescence quenching in pH range 7–10 even in the presence of several biologically and ecologically relevant metal ions. Fluorescence on–off behavior has been clearly demonstrated on the basis of the binding variability of Cu2+ to L. The binding has been elicited through the changes observed in fluorescence, absorption, ESI-MS and 1H NMR titrations. All the other thirteen metal ions studied did not show any change in the fluorescence emission. These ions do not interfere with the recognition of Cu2+ by L. The structural features of [CuL]2 complex in both the isomeric forms were established by DFT computational calculations. The utility of L has been demonstrated by showing its sensitivity toward Cu2+ on a thin layer of silica gel. The L gives sensitive fluorescence signals for Cu2+ even in blood serum and exhibits appropriate fluorescence responses in living cells.  相似文献   

14.
Chemosensors are developed to image zinc ions. Fluorescence enhancement due to Zn2+ binding is an excellent way to detect its presence. A chemosensor for Zn2+ based on dipicolylamine (DPA) groups connected by a pyridyl amide backbone has been synthesized. Addition of 2-chloroacetyl chloride to 2,6-diaminopyridine affords 2,6-bis(chloroethylamido)pyridine, which is converted to the sensor BADPA-P by 2,2′-dipicolylamine displacement of chlorine. This compound along with two others, the mono-DPA, ADPA-P and the benzyl in place of pyridyl, BADPA-B, present three potential Zn2+ sensors. It was found that BADPA-P in the presence of Zn2+ shows a large increase in fluorescence, whether in polar organic or aqueous environments. Its fluorescence in the presence of Cd2+, unlike with Zn2+, is not enhanced when excited at longer wavelengths. Proton NMR measurements, indicate two Zn2+ ions bind to BADPA-P. Also, Zn2+ enhances fluorescence even when other metal ions are present.  相似文献   

15.
A novel triphenylamine based oxidative chemosensor TOC was synthesized. The chromogenic and fluorogenic behaviors of TOC towards Hg2+ and Cu2+ ions in a binary mixture of MeCN/H2O (9/1) were dramatically different. TOC displays colorimetric ‘naked eye’ recognition of Hg2+ and fluorogenic ‘turn on’ response towards Cu2+ via a unique cyclization reaction using two different detection modes. Moreover, TOCAZOL obtained from the oxidative cyclization reaction of TOC with Cu(ClO4)2 can be used as a selective fluorescent sensor toward Hg2+ ion.  相似文献   

16.
A new simple receptor 1 based on aminosalicylimine was prepared. It exhibited an ‘off–on fluorescence type’ mode with high sensitivity in the presence of Zn2+. In particular, this chemosensor could clearly distinguish Zn2+ from Cd2+. Also, it could be a reusable chemosensor because the addition of EDTA quenched the fluorescence of the Zn2+-2·1 complex. Furthermore, receptor 1 had a sufficiently low detection limit (68 nM) in aqueous solutions, which implies that 1 could sense the nanomolar concentration of Zn2+. Therefore, this sensor has the ability to be a practical system for the monitoring of Zn2+ concentrations in aqueous samples.  相似文献   

17.
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   

18.
A click generated quinoline derivative (1) has been synthesized and used as a fluorescent probe for sequential recognition of Cu2+ and pyrophosphate (PPi) in DMSO/H2O (1:1, v/v, HEPES 20 mM, pH = 7.4) solution. Probe 1 displays high selectivity to Cu2+ ions, and the in-situ prepared probe 1-Cu2+ exhibits high selectivity toward pyrophosphate (PPi) with emission recovery of probe 1. Therefore, 1-Cu2+ complex can be applied as a fluorescence turn-on probe for PPi with high selectivity and sensitivity.  相似文献   

19.
A porphyrin derivative (1), containing two 2-(oxymethyl)pyridine units has been designed and synthesized as chemosensor for recognition of metal ions. Unlike many common porphyrin derivatives that show response to different heavy metal ions, compound 1 exhibits unexpected ratiometric fluorescence response to Zn2+ with high selectivity. The response of the novel chemosensor to zinc was based on the porphyrin metallation with cooperating effect of 2-(oxymethyl)pyridine units. The change of fluorescence of 1 was attributed to the formation of an inclusion complex between porphyrin ring and Zn2+ by 1:1 complex ratio (K = 1.04 × 105), which has been utilized as the basis of the fabrication of the Zn2+-sensitive fluorescent chemosensor. The analytical performance characteristics of the proposed Zn2+-sensitive chemosensor were investigated. The sensor can be applied to the quantification of Zn2+ with a linear range covering from 3.2 × 10−7 to 1.8 × 10−4 M and a detection limit of 5.5 × 10−8 M. The experiment results show that the response behavior of 1 to Zn2+ is pH-independent in medium condition (pH 4.0-8.0) and show excellent selectivity for Zn2+ over transition metal cations.  相似文献   

20.
A fluorescent based receptor (4Z)-4-(4-diethylamino)-2-hydroxybenzylidene amino)-1,2dihydro-1,5-dimethyl-2-phenylpyrazol-3-one (receptor 3) was developed for the highly selective and sensitive detection of Cu2+ and Zn2+ in semi-aqueous system. The fluorescence of receptor 3 was enhanced and quenched, respectively, with the addition of Zn2+ and Cu2+ ions over other surveyed cations. The receptor formed host-guest complexes in 1:1 stoichiometry with the detection limit of 5 nM and 15 nM for Cu2+ and Zn2+ ions, respectively. Further, we have effectively utilized the two metal ions (Cu2+ and Zn2+) as chemical inputs for the manufacture of INHIBIT type logic gate at molecular level using the fluorescence responses of receptor 3 at 450 nm.  相似文献   

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