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1.
A new nitrobenzoxadiazole (NBD)-based chemosensor N′-(7-nitrobenzo[c][1,2,5]oxadiazol-4-yl)thiophene-2-carbohydrazide ( NTCH) was synthesized for detecting Hg2+. NTCH could sense Hg2+ through a color change method from pale yellow to pink. Binding ratio of NTCH and Hg2+ was determined to be 1:1 with the analysis of electrospray ionization mass spectrometry and Job plot. Detection limit turned out to be 0.69 μM. In addition, NTCH could be successfully utilized for detecting Hg2+ in real water samples and visible color test strips. The probing mechanism of NTCH to Hg2+ was explained with 1H nuclear magnetic resonance (NMR) titration, Job plot, electrospray ionization mass spectrometry (ESI-MS), and theoretical calculations.  相似文献   

2.
3.
Yang YK  Tae J 《Organic letters》2006,8(25):5721-5723
A new, selective chemosensor has been developed to detect cyanide in water at micromolar concentrations. The acridinium salt used in this sensor system is prepared in a single step from an acridine orange base. Detection is based on the irreversible, 1:1 stoichiometric, nucleophilic addition of cyanide to the 9-position of the acridinium ion. This process induces a large decrease in fluorescence intensity and a marked color change. The selectivity of the system in aqueous media for CN- over other anions is remarkably high. Also, the sensitivity of both the fluorescence- and colorimetric-based assay is below the 1.9 microM suggested by the World Health Organization (WHO) as the maximum allowable cyanide concentration in drinking water. Thus, the chemodosimeter should be applicable as a practical system for the monitoring of CN- concentrations in aqueous samples. [structure: see text]  相似文献   

4.
In this study, a colorimetric and fluorescent chemosensor for mercury ions (Hg2+) was developed. Cationic polydiacetylene (PDA) vesicles with a quaternary ammonium cation and iodide as a counterion show a blue-to-red color transition; the color change is accompanied by a fluorescence enhancement in selective response to Hg2+ ions because of a perturbation of the ene–yne conjugated backbone induced by counterion exchange. It allows for selective detection of Hg2+ with the naked eye and the sensor is used to determine Hg2+ concentrations in tap water samples.  相似文献   

5.
A sensory polymeric material for the colorimetric sensing of cyanide in water has been developed based on the reactivity of this anion with the pyrylium cation.  相似文献   

6.
A spectrophotometric method for cyanide based on its inhibition of the colour formation reaction between nickel(II) and 3-(4,5-dimethyl-2-thiazolylazo)-2,6-dihydroxybenzoic acid has been developed, and allows the determination of down to 0.1 g of cyanide. Most of the interferences can be avoided by displacement of the hydrogen cyanide using an arsine generator.  相似文献   

7.
合成了含萘荧光基团的硝基取代苯腙类受体,利用紫外-可见分光光度法、荧光发射光谱法和核磁等方法研究了受体的阴离子识别与光化学传感性能. 结果表明,在DMSO有机溶剂体系中,单硝基取代受体选择性比色和荧光识别氟离子,而双硝基取代受体可以比色和荧光识别氟离子和醋酸根离子. 归因于腙=N-NH基团质子酸性的进一步增强,双硝基取代受体能够在DMSO-H2O体系中实现对氟离子的比色和荧光识别. 此类受体是有效的“off-on”型阴离子荧光传感分子.  相似文献   

8.
In this work, salicylaldehyde fluorescein hydrazone (1) was synthesized and characterized. Exhibiting reversible color changes responding to different pH in the presence of Cu(II) in buffered media, 1 could be applied as a colorimetric chemosensor for the detection of pH and Cu(II) bi-functionally. It presented a tunable system integrated with a Cu(II)-driven YES logic gate as well as an INHIBIT logic gate, with pH and Cu(II) as its chemical inputs based on encoding binary digits of logical conventions.  相似文献   

9.
Colorimetric receptors R1 and R2 have been designed and synthesized by Schiff base condensation and characterised by standard spectroscopic techniques. Anion binding ability of the receptors have been investigated quantitatively through optical, electrochemical and 1HNMR titration studies. UV-vis spectra of receptor R1 and R2 exhibited a significant red shift for F? and AcO? ions with a visual color response. Receptor R1 exhibited selective response towards AcO? ion in the presence of HEPES buffer media. Incremental color change of receptor R2 with the higher equivalence of AcO? ions clearly represent the ratiometric response. Cyclic voltammetric studies of R1 and R2 exhibits shift in oxidation and reduction peak with successive addition of AcO? ions indicating the anion induced oxidation of -NH and reduction of the keto group and nitro species. Electrooptical and 1H NMR titration studies of R2 collectively reflects the anion induced change of chromophore from C=N to N=N indicative of azo-hydrazone tautomeric signaling in the presence of AcO? ions. Lower detection limit of 2.1 and 0.41 ppm achieved with sodium salt of AcO? ion with R1 and R2 reflects their utility as colorimetric chemosensor.  相似文献   

10.
氰化物是一种快速、剧毒的化合物,能够引起组织衰竭以至机体死亡。氰化物一旦污染环境及食用源,会严重危害人体健康,当吸入或口服较大剂量氰化物时,会引起“闪电式”骤死,中毒者在10~60S内突然发出尖叫随即昏倒,出现强直性与阵发性痉挛,2-3min后呼吸停止而死亡[1]。因此加强对氰化物检测是一项重要的安全检测指标,为此,建立准确、快速,特别是能用于现场操作的氰化物测定方法有重要意义。  相似文献   

11.
A colorimetric and fluorescent cyanide probe bearing naphthol and sulfahydrazone groups has been designed and synthesized. This structurally simple probe displays a rapid response and high selectivity for cyanide in DMSO/EtOH (v/v = 2:8) solution. The addition of CN? to the sensor p-toluenesulfonyl-2-hydroxy-1-naphthylhydrazone (L3) induced a remarkable color change from pale-yellow to yellow, and green fluorescence changed to yellow. The 1H NMR titration and DFT calculations suggested that the selective sensing process is based on a nucleophilic addition reaction of cyanide to imine. Test strips based on sensor L3 were fabricated, which could act as a convenient and efficient test kit to detect CN? for “in-the-field” measurements.  相似文献   

12.
Abstract

The ensemble of 2,6-bis(2-chlorophenyl)dithiazolo[4,5-b:5',4'-e]pyridine 1 with Pd2+ ions (1?Pd2+) was prepared for the detection of cyanide ions (CN¯) in 50% aqueous methanol. Among the tested metal ions, only Pd2+ sensitively induced the red shift of the absorption bands and the complete decrease of fluorescence emission. The detection limit toward Pd2+ was 2?ppb. The ensemble 1?Pd2+ selectively and rapidly detected a low concentration of cyanide ions by a colorimetric change (40?ppb) as well as a “turn-on” fluorescent response (5?ppb). Job’s plot revealed the complex formation with 1:1 stoichiometry. The binding and replacement mode of 1?Pd2+ and CN¯ were also confirmed by 1H NMR titrations and IR analysis. In general, a fast and selective recognition of CN¯ is reported.  相似文献   

13.
A pyrene based chemosensor was designed and synthesized. The pyrene fluorophore was connected with a pyridine unit through a Schiff base structure to give the sensor (L). L was tested with a variety of metal ions and exhibited high colorimetric selectivities for Cu2+ and Fe3+ over other ions. Upon binding with Cu2+ or Fe3+, L showed an obvious optical color change from colorless to pink for Cu2+ or orange for Fe3+ over a wide pH range from 3 to 12. Moreover, the fluorescence of L at 370 nm decreased sharply after bonding with Fe3+, while other metal ions including Cu2+ had no apparent interference. Thus, using such single chemosensor, Cu2+ and Fe3+ can be detected independently with high selectivity and sensitivity. The limits of detection toward Cu2+ and Fe3+ were 8.5 and 2.0 μM, respectively. DFT calculation results also proved the formation of stable coordination complexes and the phenomenon of fluorescence quenching by Fe3+. Furthermore, L was also successfully used as a bioimaging reagent for detection of Fe3+ in living cells.  相似文献   

14.
15.
Mi Hee Kim 《Tetrahedron letters》2010,51(36):4712-10301
A colorimetric sensing ensemble was prepared by mixing readily prepared adenosine triphosphate (ATP)-stabilized AuNPs with Cu2+-phenanthroline complexes. The sensing mechanism of the ensemble was examined by UV-vis spectrometry and transmission electron microscopy. The studies showed that the Cu2+-phenanthroline complex was converted to free phenanthroline when exposed to cyanide anions and the free phenanthroline caused the ATP-stabilized AuNPs to aggregate, which in turn, resulted in a visible color change in the AuNP solution. The ensemble could detect cyanide ions in aqueous solution at physiological pH, either spectrophotometrically or visually, with high selectivity toward cyanide anions over a range of mono- and di-anions commonly found in biological and environmental systems. This sensing ensemble also allows a quantitative assay of the analyte in a neutral aqueous solution, down to a concentration of 10−5 M.  相似文献   

16.
A hybrid coumarin-hemicyanine dye, Cou-BT, was developed as a new ratiometric and colorimetric sensor for cyanide with a sensing mechanism via nucleophilic addition of cyanide anion to the benzothiolium group. Cou-BT shows high sensitivity and selectivity for cyanide detection over other common anion species in aqueous acetonitrile solution. The calculated pseudo-first-order rate constant for cyanide anion addition was (2.13 ± 0.08) × 10(-2) s(-1) at 298 K, and the detection limit was estimated to be 0.64 μM. The DFT and TDDFT calculation results suggest that the ratiometric and colorimetric sensing behavior of Cou-BT upon its reaction with cyanide was due to the interrupted π-conjugation and blocked ICT progress.  相似文献   

17.
A simple anion receptor (i.e. salicylaldehyde-indole-2-acylhydrazone) was synthesised and its recognition properties were investigated by naked-eye observation, UV–vis titration spectra, 1H NMR spectroscopy and DFT calculations. The obtained results indicated that this receptor could realise the selective colorimetric sensing and absorption ratiometric response towards AcO in CH3CN–DMSO medium, by virtue of threefold intermolecular hydrogen bonding interactions formed with phenolic OH, indole NH and amide NH.  相似文献   

18.
As a novel macrocyclic host, pillar[5]arene can selectively recognise guest molecules in organic solvents. In this study, a fluorescent chemosensor composed of a functionalised-pillar[5]arene and Cu2+ metal complex (PN–Cu), which shows good selectivity for CN? anions, has been designed and synthesised. Complexation between PN–Cu and anions has been probed by means of various fluorescence-based methods. PN–Cu, as a turn-on fluorescence chemosensor showed high selectivity towards CN? ions in comparison to other anions, and its detection limit for CN? was calculated as 9.03 × 10?7 M. The PN–Cu sensor can serve as a recyclable component in sensing materials. Moreover, the interaction between the singly functionalised pillar[5]arene and Cu2+ has been probed through various tests. Based on the remarkable selectivity of the chemosensor PN–Cu, we propose that it might be used as a potential material for CN? recognition.  相似文献   

19.
Zhaochao Xu  Jingnan Cui  Rong Zhang 《Tetrahedron》2006,62(43):10117-10122
The design, synthesis, and photophysical evaluation of a new naphthalimide-based fluorescent chemosensor, N-butyl-4-[di-(2-picolyl)amino]-5-(2-picolyl)amino-1,8-naphthalimide (1), were described for the detection of Zn2+ in aqueous acetonitrile solution at pH 7.0. Probe 1 showed absorption at 451 nm and a strong fluorescence emission at 537 nm (ΦF=0.33). The capture of Zn2+ by the receptor resulted in the deprotonation of the secondary amine conjugated to 1,8-naphthalimide so that the electron-donating ability of the N atom would be greatly enhanced; thus probe 1 showed a 56 nm red-shift in absorption (507 nm) and fluorescence spectra (593 nm, ΦF=0.14), respectively, from which one could sense Zn2+ ratiometrically and colorimetrically. The deprotonated complex, [(1-H)/Zn]+, was calculated at m/z 619.1800 and measured at m/z 618.9890. In contrast to these results, the emission of 1 was thoroughly quenched by Cu2+, Co2+, and Ni2+. The addition of other metal ions such as Li+, Na+, K+, Mg2+, Ca2+, Fe3+, Mn2+, Al3+, Cd2+, Hg2+, Ag+, and Pb2+ produced a nominal change in the optical properties of 1 due to their low affinity to probe 1. This means that probe 1 has a very high fluorescent imaging selectivity to Zn2+ among metal ions.  相似文献   

20.
ABSTRACT

A new, highly sensitive and selective chemosensing method has been developed for the detection of cyanide ion using benzamide hydrazone receptors (R1-R4). The sensing ability of these compounds towards CN? in the presence of Br ?, HSO4 ?, Cl?, OH?, I?, F?, AcO?, NO2 ? and NO3 ? in DMF and DMF-Aqueous mixture (DMF:H2O, 9:1 v/v) was investigated. The binding characteristics of the probe with cyanide ions carried out by 1 H NMR titrations indicated the deprotonation of N-H group through H-bond interactions between benzamide hydrazones and cyanide ions; it has been theoretically supported by DFT. The binding constant (Ka) and stoichiometry of the host–guest complex formed was calculated by the Benesi–Hildebrand (B–H) plot, and strong interaction of the probe with CN- ions forming a 1:2 binding stoichiometry has been noted in this study. In a DMF and aqueous medium for CN? ion, the lower limit of detection (LOD in ppm) is compared to the limit of quantification (LOQ in ppm), which is quite better in terms of sensitivity.  相似文献   

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