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1.
New rhodamine derivatives bearing urea group have been synthesized for the detection of metal ions. Especially, the dimeric system 2 displayed a selective fluorescent enhancement and colorimetric change upon the addition of Hg 2+, in which the spirolactam (nonfluorescent) to ring opened amide (fluorescent) process was utilized. The association constant of 2 with Hg 2+ was calculated as 3.2 × 10 5 M −1. 相似文献
2.
A new fluorescein-based chemodosimeter ( II) for Hg 2+ ion was designed and synthesized, and it displayed excellent selective and sensitive toward Hg 2+ ion over other commonly metal ions in aqueous media. II was a colorless, non-fluorescent compound. Upon addition of Hg 2+ 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 Hg 2+-selective chemodosimeter was developed. The fluorescence increase is linearly with Hg 2+ concentration up to 1.0 μmol L −1 with a detection limit of 8.5 × 10 −10 mol L −1 (3 σ). Compared with the rhodamine-type chemodosimeter, II is more stable in aqueous media and exhibits higher sensitivity toward Hg 2+. The findings suggest that II will serve as a practical chemodosimeter for rapid detection of Hg 2+ concentrations in realistic media. 相似文献
3.
A fluorescent probe 1 for Hg 2+ based on a rhodamine-coumarin conjugate was designed and synthesized. Probe 1 exhibits high sensitivity and selectivity for sensing Hg 2+, and about a 24-fold increase in fluorescence emission intensity is observed upon binding excess Hg 2+ in 50% water/ethanol buffered at pH 7.24. The fluorescence response to Hg 2+ is attributed to the 1:1 complex formation between probe 1 and Hg 2+, which has been utilized as the basis for the selective detection of Hg 2+. Besides, probe 1 was also found to show a reversible dual chromo- and fluorogenic response toward Hg 2+ likely due to the chelation-induced ring opening of rhodamine spirolactam. The analytical performance characteristics of the proposed Hg 2+-sensitive probe were investigated. The linear response range covers a concentration range of Hg 2+ from 8.0 × 10 −8 to 1.0 × 10 −5 mol L −1 and the detection limit is 4.0 × 10 −8 mol L −1. The determination of Hg 2+ in both tap and river water samples displays satisfactory results. 相似文献
4.
A simple fluorescent probe, which contains rhodamine and aminoquinoline moieties, was designed and prepared for selective detection of Hg 2+ in acetonitrile. RbQ exhibited high selectivity and sensitivity toward Hg 2+ over other common metal ions. The recognition of RbQ toward Hg 2+ can be detected by fluorescence spectra, absorption spectra, and even by naked eyes. The binding ratio of the RbQ–Hg 2+ 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–Zn 2+ ( RbQZ) could detect Hg 2+ 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.
A new colorimetric and fluorogenic probe ( RN3) based on rhodamine-B has been successfully designed and synthesized. It displays a selective response to Hg 2+ in the aqueous buffer solution over the other competing metals. Upon addition of Hg 2+, the solution of RN3 exhibits a ‘naked eye’ observable color change from colorless to red and an intensive fluorescence with about 105-fold enhancement. The changes in the color and fluorescence are ascribed to the ring-opening of spirolactam in rhodamine fluorophore, which is induced by a binding of the constructed receptor to Hg 2+ with the association and dissociation constants of 0.22 × 10 5 M −1 and 25.2 μM, respectively. The Job's plot experiment determines a 1:1 binding stoichiometry between RN3 and Hg 2+. The resultant “turn-on” fluorescence in buffer solution, allows the application of a method to determine Hg 2+ levels in the range of 4.0–15.0 μM, with the limit of detection (LOD) calculated at 60.7 nM (3σ/slope). In addition, the fluorescence ‘turn-off’ and color ‘fading-out’ happen to the mixture of RN3-Hg 2+ by further addition of I − or S 2−. The reversible switching cycles of fluorescence intensity upon alternate additions of Hg 2+ and S 2− demonstrate that RN3 can perform as an INHIBIT logic gate. Furthermore, the potential of RN3 as a fluorescent probe has been demonstrated for cellular imaging. 相似文献
6.
A rhodamine spirolactam derivative ( 1) is developed as a colormetric and fluorescent probe for trivalent aluminum ions (Al 3+). It exhibits a highly sensitive “turn-on” fluorescent response toward Al 3+ with a 70-fold fluorescence intensity enhancement under 2 equiv. of Al 3+ added. The probe can be applied to the quantification of Al 3+ with a linear range covering from 5.0 × 10 −7 to 2.0 × 10 −5 M and a detection limit of 4.0 × 10 −8 M. Most importantly, the fluorescence changes of the probe are remarkably specific for Al 3+ in the presence of other metal ions, which meet the selective requirements for practical application. Moreover, the experiment results show that the response behavior of 1 towards Al 3+ is pH independent in neutral condition (pH 6.0–8.0) and the response of the probe is fast (response time less than 3 min). In addition, the proposed probe has been used to detect Al 3+ in water samples and image Al 3+ in living cells with satisfying results. 相似文献
7.
A novel fluorescent ratiometric chemosensor based on 4-pyren-1-yl-pyrimidine ( PPM) has been designed and prepared for the detection of Hg 2+ in the presence of other competing metal ions in acetonitrile. The photo exhibits fluorescence color change of PPM from blue to green without and with Hg 2+, which red shift of wavelength about 105 nm in fluorescence emission spectra. It can serve as a highly selective chemodosimeter for Hg 2+ with ratiometric and naked-eye detection. The photophysical properties of PPM confirmed a 2:1 ( PPM–Hg 2+) binding model and the spectral response toward Hg 2+ was proved to be reversible. 相似文献
8.
Naphthalimide derivative (compound 1) containing hydrophilic hexanoic acid group was synthesized and used to recognize Hg 2+ in aqueous solution. The fluorescence enhancement of 1 is attributed to the formation of a complex between 1 and Hg 2+ by 1:1 complex ratio ( K = 2.08 × 10 5), which has been utilized as the basis of fabrication of the Hg 2+-sensitive fluorescent chemosensor. The comparison of this method with some other fluorescence methods for the determination of Hg 2+ indicated that the method can be applied in aqueous solution rather than organic solution. The analytical performance characteristics of the proposed Hg 2+-sensitive chemosensor were investigated. The chemosensor can be applied to the quantification of Hg 2+ 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 Hg 2+ is pH independent in medium condition (pH 4.0–8.0). Most importantly, the fluorescence changes of the chemosensor are remarkably specific for Hg 2+ in the presence of other metal ions, which meet the selective requirements for practical application. Moreover, the response of the chemosensor toward Hg 2+ is fast (response time less than 1 min). In addition, the chemosensor has been used for determination of Hg 2+ in hair samples with satisfactory results, which further demonstrates its value of practical applications. 相似文献
9.
A rhodamine spirolactam derivative ( 1) was developed as a colormetric and fluorescent chemosensor for adenosine-5′-triphosphate (ATP) via hydrogen bonds interaction. As far as we know, this is the first case to explore ATP-induced ring-opening of spirolactam in rhodamine derivatives. It exhibited a highly sensitive “turn-on” fluorescent response toward ATP with a 47-fold fluorescence intensity enhancement under 20 equiv. of ATP added. The chemosensor can be applied to the quantification of ATP with a linear range covering from 1.0 × 10 −7 to 2.0 × 10 −4 M and a detection limit of 2.5 × 10 −8 M. The experiment results show that the response behavior of 1 toward ATP is pH independent in medium condition (pH 6.0–8.0). Most importantly, the novel chemosensor has well solved the problem of serious interferences from other nucleoside polyphosphates such as ADP and AMP generally met by previously reported typical fluorescent chemosensors for ATP. Moreover, the response of the chemosensor toward ATP is fast (response time less than 3 min). In addition, the chemosensor can be used for the fluorescence assay for protein kinase activity with satisfactory results. The chemosensor for ATP based on hydrogen bonds interaction provided a novel strategy for the design of colormetric and ratiometric fluorescent probes for other target anions with high sensitivity and selectivity. 相似文献
10.
For a better insight into the spectroscopic properties of [2.2]paracyclophane in fluorescent probes, a novel rhodamine-based chemodosimeter bearing [2.2]paracyclophane 4a has been designed and synthesized. The probe 4a exhibits a highly selective and sensitive response to Hg 2+ over other transition metal ions in aqueous solution. Its detection limit is determined to be 77 nM. The significant changes in the fluorescence color could be used for the naked-eye detection. Furthermore, the probe 4a shows good membrane permeability and can be applied to detect intracellular Hg 2+ in human lung adenocarcinoma cells (A549 cells). The crystal structure and spectral properties of its congener 4b that contains one 12-bromo [2.2]paracyclophane group and rhodamine moiety are also investigated for a comparison. 相似文献
11.
A new indole-based fluorescent chemosensor 1 was prepared and its metal ion sensing properties were investigated. It exhibits high sensitivity and selectivity toward Hg 2+ among a series of metal ions in H 2O-EtOH (7:1, v/v). The association constant of the 1:1 complex formation for 1-Hg 2+ was calculated to be 9.57 × 10 3 M −1, and the detection limit for Hg 2+ was found to be 2.25 × 10 −5 M. Computational results revealed that 1 and Hg 2+ ion formed with a central tetrahedron-coordinated Hg 2+. 相似文献
12.
A new multi-responsive fluorescent switch DTE-Pip-Rho 1O has been designed and synthesized in this study. For this molecule, the reactive site of spirolactam ring is far away from the diarylethene unit through the intramolecular piperazine. It exhibited high selectivity and sensitivity to Hg 2+ in addition to obvious color change (colorless-pink) and fluorescence “off-on” (dark-orange) during this process. It is believed that the color change is due to Hg 2+-assisted hydrolysis of rhodamine hydrazide. Therefore, the new molecule can be used as colorimentric and fluorescent chemosensor for Hg 2+ with high selectivity. The detection limits of absorbance and fluorescence for Hg 2+ were calculated to be 1.15?μM and 1.16?μM, respectively. The resulting DTE-Pip-Rho 1O-Hg2+ could also function as a reversible fluorescence photo-switch in response to UV/vis light owing to FRET mechanism. Moreover, it has been demonstrated that the photo-switchable system displayed excellent fatigue resistance and remarkable anti-photobleaching capability. 相似文献
13.
Highly selective detection of Hg 2+ ion has been achieved using the push–pull-type purine nucleoside-based fluorescent sensor L1. The sensor L1 incorporating aza-18-crown-6 at C6 position of purine nucleoside, is highly sensitive and selective toward Hg 2+ ion in CH 3CN–H 2O mixture (92/8, v/v). The detection limit for the fluorescent sensor L1 toward Hg 2+ ion is 7.8 × 10 −8. 相似文献
14.
Novel mesoporous silica-immobilized rhodamine ( MSIR) and silica particle-immobilized rhodamine ( SPIR) anchored by a tren (N(CH 2CH 2NH 2) 3) were synthesized. The binding and adsorption abilities of both MSIR and SPIR for metal cations were investigated with fluorophotometry and ion chromatography, respectively. Both MSIR and SPIR show selectivity for Hg 2+ ion over other metal cations because the Hg 2+ ion selectively induces a ring opening of the rhodamine fluorophores. The sensitivity of the MSIR for Hg 2+ ion is greater than that of the SPIR and the MSIR adsorbs 70% of Hg 2+ ion while the SPIR does only 40%. The MSIR can be also easily recovered by treatment of a solution of TBA +OH −. For the application of Hg 2+ detection in the environmental field, the MSIR-coated glass plate is also developed and exhibits an excellent function in visual and fluorescence changes with Hg 2+ ion. 相似文献
15.
Two novel thioxanthone-based compounds 1a and 1b which possess thiosemicarbazone as binding site were developed for the dual-channel detection of Hg 2+ and F −. Upon treatment with Hg 2+ and F − separately, the probes’ fluorescence is effectively quenched, meanwhile 1a and 1b show evident naked-eye color variations after addition of F −: colorless to yellow. They both exhibit specific sensitivity and selectivity for Hg 2+ or F − over other examined ions in tetrahydrofuran (THF) solution. 相似文献
16.
A fluorescent and colorimetric sensor based on rhodamine 6 g (RD6g) was designed, synthesized, and characterized using microwave irradiation. The sensing behavior of this compound was studied by UV–visible and fluorescence spectroscopy. Sensor RD6g exhibits a high selectivity and an excellent sensitivity and is a dual-responsive colorimetric and fluorescent Hg2+-specific sensor in aqueous buffer solution. Mercury ions give rise to the development of a very fluorescent ring-open amide spirolactam system. The detection limit for Hg2+ was found to be 1.2?×?10?8 M. The binding ratio of RD6g-Hg2+ complex was determined to be 1:1 according to the Job’s plot. The reversibility of RD6g?Hg2+ complex has been achieved with CN? anions. The test strip based on RD6g was developed, which could be used as a suitable and methodical Hg2+ test kit.
相似文献
17.
A novel S, S′-diallyl carbohydrazonodithioate derivative 3 of rhodamine B hydrazone was developed as a chemodosimeter for selective detection of mercury ions based on Hg 2+ promoted cyclization. The allyl groups of 3 play a key role in the binding and selection of Hg 2+ ions. The probe responds selectively to Hg 2+ over various other competitive cations with marked chromo- and fluorogenic changes. The formation of stable oxadiazole derivative 8 was a strong driving force for this high selectivity. Practically, this probe is more promising because of the remarkable high selectivity, faster response, low detection limit, and aqueous solubility of 3. 相似文献
18.
A novel Cu 2+-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 Cu 2+-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 Cu 2+, 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 Cu 2+. 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 Cu 2+ in living cells with satisfying results, which further displayed its valuable applications in biological systems. 相似文献
19.
A new sensing molecule 8-hydroxyquinoline ferrocenoate ( Fc-Q) which combines ferrocene and 8-hydroxyquinoline moieties was synthesized and applied as a multi-channel sensor for the detection of Hg 2+ ion. Fc-Q can coordinate with Hg 2+ to give colorimetric, fluorescent and electrochemical responses. Upon complexation with Hg 2+ ion, the characteristic absorption peak is red-shifted (Δ λ = 45 nm), the fluorescent intensity is quenched at 303 nm, and the oxidation peak is cathodic shifted (Δ E1/2 = −149 mV). Quantitatively analyzed Hg 2+ ions at the range of ppb level could be achieved by electrochemical response. For the practical application of sensing Hg 2+ in real world water, Fc-Q modified screen-printed carbon electrodes were obtained for facile, sensitive, and on-site analysis of Hg 2+. 相似文献
20.
A system based on FRET mechanism, comprising a coumarin donor and a rhodamine acceptor, was developed for the selective and quantitative detection of metal ions. Fluorescent chemosensors RCs, linked by 1,2-diethylamine, exhibit significant fluorescence enhancement and excellent selectivity toward Cu 2+. Fluorescent probes CRB and CR6G, linked by hydrazide, function as ratiometric receptors for Cu 2+ chromogentically and fluorogentically in organic-aqueous media. Furthermore, the characteristic rhodamine-based fluorescence response of CRB (excitation at 550 nm) exhibits high selectivity for Hg(II). The construction of this kind of universal FRET system opens a broader prospect for future design of ratiometric fluorescent probes. 相似文献
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