一个新的具有双光子诱导荧光测量能力的在水中对铅离子有选择性的荧光探针

报道了一个对Pb^2＋具有很好选择性的探针1,其荧光团部分为：1,4-二氰基-2,5-联（苯乙烯基）苯;配体为：[（2-羧基甲氧基-苯基）-羧基甲基-胺基]-乙酸．在探针1的水溶液中滴加铅离子,它的荧光发射光谱发生变化,在590nm处出现一个新的宽带峰．探针1在生理环境的pH范围内不受pH的影响,并且在740nm,它的双光子吸收截面为最大：51GM．     

A new fluorescent sensor selective for Pb<Superscript>2+</Superscript> in water capable of two-photon-induced fluorescence measurement

A new fluorescent sensor (1) for Pb²⁺ containing a 1,4-dicyano-2,5-bis(styryl)benzene fluorophore and 2-(N,N′-bis(carboxylmethyl))amino-1-carboxylmethoxylbenzene as receptor has been synthesized. The sensor selectively responds to Pb²⁺ in the aqueous environment, and brings about similar and significant changes in one- and two-photon excited emission spectra: λ _max red-shift from 460 (519) to 590 nm. The selective response is pH-independent in a large physiological pH range, and two-photon action cross section (ϕδ) is 51 GM (1 GM = 1×10⁻⁵⁰ cm⁴·s·photon⁻¹·molecule⁻¹) at 740 nm. Supported by the National Natural Science Foundation of China (Grant Nos. 20705621 & 20706008), the National Basic Research Project of China (Grant No. 2009CB724706), the Ministry of Education of China, Changjiang Scholars Innovative Research Team in University (Grant No. IRT0711) and Cultivation Fund of the Key Scientific and Technical Innovation Project (Grant No. 707016)     

A new perylene diimide-based colorimetric and fluorescent sensor for selective detection of Cu<Superscript>2+</Superscript> cation

A new perylene diimide (PDI) ligand (1) functionalized with a dipicolylethylenediamine (DPEN) moiety was synthesized and first used as a colorimetric and fluorometric dual-channel sensor to specifically detect the presence of Cu²⁺ over a wide range of other cations. The solution of 1 (10 μmol/L) upon addition of Cu²⁺ displayed distinguishing pink color compared with other cations including K⁺, Ni²⁺, Ca²⁺, Mn²⁺, Na⁺, Sr²⁺, Zn²⁺, Co²⁺, Cd²⁺, Mg²⁺, Cr³⁺, Ag⁺, and Ba²⁺, indicating the sensitivity and selectivity of 1 to Cu²⁺. Thus, the advantage of this assay is that naked-eye detection of Cu²⁺ becomes possible. Moreover, among these metal ions investigated, only Cu²⁺ quenched more than half fluorescent intensity of 1. The ESI-TOF spectrum of a mixture of 1 and CuCl₂ in combination of the fluorescence titration spectra of 1 (10 μmol/L) upon addition of various amounts of Cu²⁺ revealed the formation of a 2:1 metal-ligand complex through the metal coordination interaction. Supported by the National Natural Science Foundation of China (Grant Nos. 20872101 & 20772086)     

A new tripodal rhodamine B derivative as a highly selective and sensitive fluorescence chemosensor for copper(II)

A new tripodal rhodamine B derivative 2 was designed and synthesized by tripodal trialdehyde and rhodamine B hydrazide for the first time. This derivative could be used as a fluorescent chemosensor for the selective and sensitive determination of copper(II) in Tris-HCl buffer and ethanol aqueous mixed media. Under the optimum conditions described herein, fluorescence enhancement at 557/577 nm was linearly related to the concentration of copper(II) in the range of 0.10 to 10.00×10⁻⁵ mol·L⁻¹, with a correlation coefficient of R ²=0.9964 (n=15) and a detection limit of 1.129×10⁻⁷ mol·L⁻¹ (the relative standard deviation for five repeated measurements at 4.00×10⁻⁵ mol·L⁻¹ Cu(II) was 2.2%). The absorbance measurements at 557 nm were linearly related to the concentration of Cu(II) in the range of 0.50 to 25.00×10⁻⁵ mol·L⁻¹, with a correlation coefficient of R ²=0.9948 (n=13) and a detection limit of 3.338×10⁻⁷mol·L⁻¹. Supported by the Foundation of the Governor of Guizhou Province, China (Grant No. 200617) and the Talented Person Foundation of Guizhou University (Grant No. 2007039)     

A new perylene diimide-based colorimetric and fluorescent sensor for selective detection of Cu~(2+) cation

A new perylene diimide (PDI) ligand (1) functionalized with a dipicolylethylenediamine (DPEN) moiety was synthesized and first used as a colorimetric and fluorometric dual-channel sensor to specifically detect the presence of Cu2+ over a wide range of other cations. The solution of 1 (10 μmol/L) upon ad-dition of Cu2+ displayed distinguishing pink color compared with other cations including K+,Ni2+,Ca2+,Mn2+,Na+,Sr2+,Zn2+,Co2+,Cd2+,Mg2+,Cr3+,Ag+,and Ba2+,indicating the sensitivity and selectivity of 1 to Cu...     

A novel fluorescent sensor for hydrophobic amines in aqueous solution

A novel fluorescent tweezer was designed and synthesised to sense hydrophobic amines in aqueous solution. Association of the guest was driven by both hydrophobic effect and electrostatic interactions, with the hydrophobic interactions being dominant. The affinity and selectivity of the sensor for amine-based stimulants are reported.     

A highly selective fluorescent sensor for Ca2+ and Sr2+ based on diarylethene with a furan-carbohydrazide unit

A fluorescent sensor based on diarylethene has been designed and synthesized. The sensor not only exhibited excellent photochromic properties, but also has distinguishing ability for Ca²⁺ and Sr²⁺ from other metal ions. Upon addition of Ca²⁺ and Sr²⁺, its emission intensity enhanced 27-fold and 24-fold respectively, accompanied by the emission peak shifted from 439 nm to 484 nm for Ca²⁺, and to 479 nm for Sr²⁺. The 1:1 stoichiometry between the sensor and the two ions was confirmed by Job's plot and HRMS. The LOD for Ca²⁺ and Sr²⁺ was determined to be 9.4 × 10^?8 mol L^?1 and 7.2 × 10^?8 mol L^?1, respectively. Furthermore, the sensor was applied in the detection of Ca²⁺ and Sr²⁺ in practical samples successfully.     

Turn-on fluorescent sensor for selective detection of Zn(2+), Cd(2+), and Hg(2+) in water

A new fluorescent chemosensor based on a helical imide as fluorophore and a cyclen moiety as ionophore was synthesized, which not only showed enhanced fluorescent responses in the presence of Zn(2+), Cd(2+), and Hg(2+) but also could simultaneously and selectively distinguish the three cations in a simulated physiological condition with the help of cysteine as an auxiliary reagent.     

A selective fluorescent sensor for Pb(II) in water

A new fluorescent sensor (1) containing bis(2-pyridylmethyl)amine group as a binding moiety for Pb²⁺ was developed. Compound 1 shows selective response to Pb²⁺ over other metal ions in pH 7.0 HEPES buffer solution. The fluorescence intensity enhancement was ascribed to the complex formation between Pb²⁺ and 1 which blocked the photo-induced electron transfer process.     

Magnesium-tetrazaporphyrin incorporated PVC matrix as a new material for fabrication of Mg(2+) selective potentiometric sensor

Membrane incorporating [Mg{(TAP)(SBn)₈}] complex, (I), as ionophore with composition I:NaTPB:DOP:PVC in the ratio 10:2:133:200 (w/w) exhibits the best result for potentiometric sensing of Mg²⁺ ions. This gives linear potential response in the concentration range of 9.4×10⁻⁶ to 1.0×10⁻¹ M with a slope of 29.2±0.4 mV per decade of activity of Mg²⁺. Standard deviation in observed values of potentials in this concentration range, from the least square fit line, found to be 2.91 mV with 90% confidence limit lying within ±0.4 mV per decade of activity. The electrode works satisfactorily in the pH range 3.5-7.8 and shows a fast response time of 13±2 s. It shows good selectivity for Mg²⁺ over other mono-, bi- and tri-valent cations. Only K⁺ and Zn²⁺ cause slight interference if present at concentrations ≥1.0×10⁻⁵ M. The electrode is durable and can be used over a period of 5 months with good reproducibility (∼1% error). It has been successfully used as an indicator electrode in potentiometric titration of Mg²⁺ against EDTA as well as for the determination of Mg²⁺ in simulated mixtures.     

A highly selective fluorescent sensor for Cu based on 2-(2′-hydroxyphenyl)benzoxazole in a poly(vinyl chloride) matrix

This paper describes a copper selective optical chemical sensor based on static quenching of the fluorescence of 2-(2′-hydroxyphenyl)benzoxazole entrapped in a poly(vinyl chloride) (PVC) membrane. The effect of the composition of the sensing membrane was studied, and experimental conditions were optimized. The sensors exhibit stable response over the concentration range from 4.0 × 10⁻⁸ M to 5.0 × 10⁻⁵ M Cu²⁺ at pH 4.0-6.5, and a high selectivity. The response time for Cu²⁺ with concentration ≤5 × 10⁻⁶ M is less than 7 min. The optode can be regenerated using 0.1 M HCl and acetate buffer solution. The sensor has been used for direct measurement of copper content in river water samples with a relative error less than 4% with reference to that obtained by atomic absorption spectrometry.     

A fluorescent Cd(II) based 2-D coordination polymer for highly selective detection of nitroaromatics and Hg2+

A 2-D Cd(II) coordination polymer (CP), {[Cd₂(L)₂(4,4′-bipy)₂(H₂O)?7H₂O]_n (1), has been synthesized using 5-aminoisophthalic acid (H₂L) as ligand and 4,4′-bipyridine as co-ligand. A single-crystal X-ray diffraction study shows that 1 is an infinite 2-D layer. CP 1 behaves as a highly selective and sensitive fluorescence chemosensor for detection of Hg²⁺ and 2,4,6-trinitrotoluene (TNT). Furthermore, possible emission quenching in 1 in the presence of nitroaromatics has been addressed with the aid of theoretical calculations. The calculations indicated that there are both electron and energy transfer processes, in addition to electrostatic interaction between 1 and nitroaromatics which contributes to the selective fluorescence quenching.     

Benzimidazolium-based new simple ratiometric fluorescent sensor for selective detection of dihydrogenphosphate

A series of pyridine-coupled benzimidazolium-based receptors 1, 2 and 3 have been designed and synthesised. In the series, only receptor 1 is structurally appealing in the selective recognition of H₂PO₄^?  in CHCl₃ as well as in CH₃CN over a series of other anions. The ratiometric change in emission with a triplet band at 420 nm is the distinctive feature of selective recognition of H₂PO₄^?  in CHCl₃. In CH₃CN, a ‘turn on’ response is selectively observed. Binding studies have been carried out using fluorescence, UV–vis, ¹H NMR and ³¹P NMR spectroscopic techniques. Experimental results have been correlated with the theoretical findings.     

Utilization of a spiropyran derivative in a polymeric film optode for selective fluorescent sensing of zinc ion

Spiropyrans are the most studied families of func- tional materials due to their reversible structural con- version in response to external optical, chemical, and thermal stimulation[1]. Irradiation with ultraviolet light causes formation of an extended π-conjugation open form (merocyanine form) by heterolytic cleavage of the C (spiro)-O bond, which generates an intense ab- sorption in the visible region. Under the irradiating of visible light, the opened form will come back to the closed spi…     

A cost-effective and practical polybenzanthrone-based fluorescent sensor for efficient determination of palladium (II) ion and its application in agricultural crops and environment

A highly selective and sensitive fluorescent chemosensor suitable for practical measurement of palladium ion (Pd²⁺) in agricultural crops and environment samples has been successfully fabricated using polybenzanthrone (PBA). PBA was facilely electrosynthesized in the mixed electrolyte of acetonitrile and boron trifluoride diethyl etherate. The fluorescence intensity of PBA showed a linear response to Pd²⁺ in the concentration range of 5 nM–0.12 mM with a detection limit of 0.277 nM and quantification limit of 0.925 nM. Different compounds existing in agricultural crops and environment such as common metal ions, anions, natural amino acids, carbohydrates, and organic acids were used to examine the selectivity of the as-fabricated sensor, and no obvious fluorescence change could be observed in these interferents and their mixtures. A possible mechanism was proposed that the coordination of PBA and Pd²⁺ enhance the aggregation of polymer chains, which led to a significant quenching of PBA emission, and this was further confirmed by absorption spectra monitoring and transmission electron microscopy. The excellent performance of the proposed sensor and satisfactory results of the Pd²⁺ determination in practical samples suggested that the PBA-based fluorescent sensor for the determination of Pd²⁺ will be a good candidate for application in agriculture and environment.     

A highly selective fluorescence chemosensor for Pb(II) in neutral buffer aqueous solution

A 3,4-dimethylthieno[2,3-b]thiophene-based fluorogenic probe bearing benzo[d]-thiazole-2-thio unit (sodium 3,4-bis ((benzo[d]thiazol-2-ylthio)methyl) thieno [2, 3-b]thio-phene-2, 5-dicarboxylate) was developed as a novel fluorescent chemosensor with high selectivity towards Pb(II) over other cations tested. The new probe exhibited good water solubility and only sensed Pb(II) among metal ions examined in neutral 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid buffer solution. The selectivity and sensitivity of fluorogenic probe to Pb(II) were discussed on the basis of experimental results.     

Ratiometric chemosensor for fluorescent determination of Zn2+ in aqueous ethanol

A new ratiometric and selective fluorescent chemosensor (1) for quantification of zinc ions in aqueous ethanol has been synthesized and investigated in this work. In an environmentally friendly media of 30% (v/v) water/ethanol and 10 mM Tris-HCl neutral buffer (pH 7.03), 1 displayed selective Zn²⁺ ratiometric fluorescence response, with a dynamic working range of 1.0-8.0 μM and a detection limit of 0.5 μM Zn²⁺. The determination of Zn²⁺ in synthesized water sample was also successful.     

A simple and highly selective fluorescent sensor for palladium based on benzofuran-2-boronic acid

Benzofuran-2-boronic acid could be used as a fluorescent sensor for the detection of Pd²⁺ because it was rapidly converted to highly fluorescent derivative after mixing with Pd²⁺ under basic condition at room temperature. We found that dimerization of benzofuran was occurred to form fluorescent derivative by the catalytic activity of palladium. The fluorescence intensity at 360 nm increased with increasing the concentration of Pd²⁺. The excellent selectivity for Pd²⁺ was demonstrated among other metal ions. Based on this findings, we successfully applied benzofuran-2-boronic acid to develop a microplate-based assay for high-throughput measurement of Pd²⁺. The detection limit (blank + 3SD) for Pd²⁺ of the proposed assay was 9.8 nM.