一种新型比色荧光双通道水相检测氰根离子的化学传感器

合成了一种新型的,能在含水介质中比色荧光双通道单一选择性识别CN^-的传感器分子1-羟基萘甲叉酰肼乙基-3-羟基萘甲叉酰肼甲基苯并咪唑溴鎓盐(J1)。 在J1的DMSO/H₂O (体积比3:2)HEPES 的缓冲体系(pH=7.2)中分别加入F^-、Cl^-、Br^-、I^-、AcO^-、HSO₄^-、ClO₄^-、H₂PO₄^-、SCN^-和CN^-等阴离子后,只有CN^-的加入会使得溶液颜色发生明显的变化,由无色变为深黄色。 相应地在J1的DMSO/H₂O (体积比4:1)HEPES的缓冲体系(pH=7.2)中加入CN^-,溶液发出明亮的黄色荧光。 这一识别过程,不会受到其它阴离子的干扰。 紫外-可见光谱的最低检测限为1.57×10^-7 mol/L,检测线性范围为3.875×10^-4~2.15×10^-2 mol/L。 荧光光谱的最低检测限为4.63×10^-6 mol/L,检测线性范围为0.8×10^-4~1.60×10^-3 mol/L。 此结果表明,J1是一种良好的用于识别 CN^-的化学传感器,在含水介质中对CN^-具有选择性好、灵敏度高以及抗干扰性强的识别性能。 与此同时,基于J1对于CN^-的高选择性识别我们制备了CN^-的检测试纸,该试纸能够方便、快捷、准确地检测水中的CN^-。     

Selective Chemosensor of Fe3+ Based on Fluorescence Quenching by 2,2′‐Bisbenzimidazole Derivative in Aqueous Media

2,2′‐Bisbenzimidazole derivative ( L ) was designed as a fluorescent chemosensor for Fe³⁺. This structurally simple chemosensor displays significant fluorescence quenching with increasing concentrations of Fe³⁺. L exhibited high selectivity and antidisturbance for Fe³⁺ among environmentally relevant metal ions in aqueous media. The method of Job's plot indicated the formation of 1:2 complex between L and Fe³⁺, and the possible binding mode of the system was also proposed. In addition, further study demonstrates the detection limit on fluorescence response of the sensor to Fe³⁺ is down to 10^?7 mol·L^?1 range. The binding mode was investigated by fluorescence spectra, ESI‐MS, IR data, ¹H NMR, ¹³C NMR and crystal data.     

A Dual Colorimetric/Fluorescence System for Determining pH Based on the Nucleophilic Addition Reaction of an o‐Hydroxymerocyanine Dye

Owing to their ability to monitor pH in a precise and rapid manner, optical probes have widely been developed for biological and nonbiological applications. The strategies thus far employed to determine pH rely on two types of processes including reversible protonation of amine nitrogen atoms and deprotonation of phenols. We have developed a novel dual, colorimetric/fluorescence system for determining the pH of a solution. This system utilizes an o‐hydroxymerocyanine dye that undergoes a nucleophilic addition reaction that subsequently causes reversible structural changes interconverting a merocyanine to a spirocyanine and a spirocyanine to a spiropyran. It was demonstrated that the dye can be employed to measure the pH of solutions in the 2.5–5.75 and 9.6–11.8 ranges with color changes from yellow to dark blue and then to lavender. Moreover, the fluorescence response associated with the spirocyanine–spiropyran transformation of the dye occurring in alkaline solutions provides a precise method.     

A New Fluorescent Chemosensor for Cu2+ Based on 1,2,3,4,5,6,7,8,9,10‐Decahydroacridine‐1,8‐dione Fluorophore

A new chemosensor for Cu²⁺ was synthesized based on 1,2,3,4,5,6,7,8,9,10‐decahydroacridine‐1,8‐dione dyes, which exhibited an obvious fluorescent selectivity to the sensing of Cu²⁺ ions over other cations, such as Na⁺, K⁺, Ca²⁺, Cd²⁺, Co²⁺, Hg²⁺, Mg²⁺, Mn²⁺, Ni²⁺, Zn²⁺, Ag⁺ and Pb²⁺. Moreover, it presented a fluorescent switch function when EDTA was added to the compound‐Cu²⁺ complex in examined systems.     

A PEGylated Fluorescent Turn‐On Sensor for Detecting Fluoride Ions in Totally Aqueous Media and Its Imaging in Live Cells

Owing to the considerable significance of fluoride anions for health and environmental issues, it is of great importance to develop methods that can rapidly, sensitively and selectively detect the fluoride anion in aqueous media and biological samples. Herein, we demonstrate a robust fluorescent turn‐on sensor for detecting the fluoride ion in a totally aqueous solution. In this study, a biocompatible hydrophilic polymer poly(ethylene glycol) (PEG) is incorporated into the sensing system to ensure water solubility and to enhance biocompatibility. tert‐Butyldiphenylsilyl (TBDPS) groups were then covalently introduced onto the fluorescein moiety, which effectively quenched the fluorescence of the sensor. Upon addition of fluoride ion, the selective fluoride‐mediated cleavage of the Si? O bond leads to the recovery of the fluorescein moiety, resulting in a dramatic increase in fluorescence intensity under visible light excitation. The sensor is responsive and highly selective for the fluoride anion over other common anions; it also exhibits a very low detection limit of 19 ppb. In addition, this sensor is operative in some real samples such as running water, urine, and serum and can accurately detect fluoride ions in these samples. The cytotoxicity of the sensor was determined to be Grade I toxicity according to United States Pharmacopoeia and ISO 10993‐5, suggesting the very low cytotoxicity of the sensor. Moreover, it was found that the senor could be readily internalized by both HeLa and L929 cells and the sensor could be utilized to track fluoride level changes inside the cells.     

1,8-萘酰亚胺为发色团的Zn2+荧光探针的合成及性能研究

合成了以1,8-萘酰亚胺为发色团,以联吡啶为离子受体的Zn²⁺荧光探针,并进行了表征及离子识别性能的研究。研究表明该化合物对Zn²⁺具有良好的识别性能,同时相对于Ca²⁺, Cd²⁺, Co²⁺, Cu²⁺, Hg²⁺, Fe³⁺, Mn²⁺, Ni²⁺, Pb²⁺等金属离子具有良好的选择性。     

Reaction‐Based Colorimetric and Ratiometric Fluorescence Sensor for Detection of Cyanide in Aqueous Media

A stilbene‐based compound ( 1 ) has been prepared and was highly selective for the detection of cyanide anion in aqueous media even in the presence of other anions, such as F^?, Cl^?, Br^?, I^?, ClO₄^?, H₂PO₄^?, HSO₄^?, NO₃^?, and CH₃CO₂^?. A noticeable change in the color of the solution, along with a prominent fluorescence enhancement, was observed upon the addition of cyanide. The color change was observed upon the nucleophilic addition of the cyanide anion to the electron‐deficient cyanoacrylate group of 1 . The spectral changes induced by the reaction were analyzed by comparison with two model compounds, such as compound 2 with dimethyl substituents and compound 3 without a cyanoacrylate group. An intramolecular charge‐transfer (ICT) mechanism played a key role in the sensing properties, and the mechanism was supported by DFT/TDDFT calculations.     

Bulk Aggregation Based Fluorescence Turn‐On Sensors for Selective Detection of Progesterone in Aqueous Solution

Steroids are polycyclic compounds that share tetracyclic ring as core scaffold, and selective detection of a steroid is challenging owing to their structural similarities. The discovery of chemosensors that recognize progesterone by alteration of self‐aggregation state is described, and these show significant fluorescence turn‐on. A self‐aggregated 48‐membered dansyl library was screened against a series of metabolites in aqueous buffer and discovered two compounds ( PG‐1 , PG‐2 ) exhibited exceptional selectivity for progesterone. Following studies of aggregation properties of probes using dynamic light scattering and transmission electron microscopy supports progesterone recognition lead to the generation of bulk aggregates that induce fluorescence enhancement. Though many fluorescence sensing mechanisms have been proposed, a sensing mode based on the bulk aggregate formation of fluorophore has never been reported, and this may open a new avenue of chemosensor design.     

基于喹啉衍生物的汞离子选择性荧光传感分子的合成与应用

合成一种新型开-关(ON-OFF)型汞离子荧光传感分子triquinolin-8-yl benzene-1,3,5-tri-carboxylate（TQBTC）。 采用FT-IR、元素分析、¹H NMR测试技术对其结构进行了表征。 在对其荧光性质的研究中发现,TQBTC的乙腈-水溶液在253.0 nm波长辐射激发下于616.0 nm处发射强荧光,且对汞离子络合有较好的选择性。 TQBTC与Hg(Ⅱ)可形成1∶3型络合物,同时使荧光线性猝灭,TQBTC可作为Hg(Ⅱ)的荧光传感分子。 建立了一种测定Hg(Ⅱ)的灵敏分析方法。 Hg(Ⅱ)浓度在0~30 μmol/L的范围内与TQBTC的荧光猝灭呈线性关系,方法检出限为0.838 μmol/L。 方法应用于实际样品中Hg(Ⅱ)的检测,获得满意结果。     

Sulfonamide and Morpholine‐Based Dual Chemosensor for Cu2+ and Ag+ in Different Solvent Media

The detection of cations has attracted considerable interest because of their importance in various physiological processes. In this study, compound 1 bearing sulfonamide and morpholine functionalities was synthesized. Its structure was well characterized by NMR spectroscopy and mass spectrometry. UV/vis absorption spectra and fluorescence spectra indicated that it displayed high sensitivity and selectivity for Cu²⁺ and Ag⁺ by switching solvent media. It means that: (1) it showed selective response to Cu²⁺ in acetonitrile, (2) whereas it exhibited high selectivity for Ag⁺ in water. The density functional theory calculations were used to clearly explain the different recognition behaviors in different solvent media. This research suggests that compound 1 bearing sulfonamide and morpholine functionalities could act as a multifunctional chemosensor for monitoring multiple cations by changing solvent media and provides an alternative approach to design novel dual cations chemosensors.     

Fluorescent Detection of Hypochlorous Acid from Turn‐On to FRET‐Based Ratiometry by a HOCl‐Mediated Cyclization Reaction

Hypochlorous acid (HOCl), a reactive oxygen species (ROS), plays a significant biological role in living systems. However, abnormal levels of HOCl are implicated in many inflammation‐associated diseases. Therefore, the detection of HOCl is of great importance. In this work, we describe the HOCl‐promoted cyclization of rhodamine‐thiosemicarbazides to rhodamine‐oxadiazoles, which is then exploited as a novel design strategy for the development of a new fluorescence turn‐on HOCl probe 2 . On the basis of the fluorescence resonance energy transfer (FRET) signaling mechanism, 2 was further converted into 1 a and 1 b , which represent the first paradigm of FRET‐based ratiometric fluorescent HOCl probes. The outstanding features of 1 a and 1 b include well‐resolved emission peaks, high sensitivity, high selectivity, good functionality at physiological pH, rapid response, low cytotoxicity, and good cell‐membrane permeability. Furthermore, these excellent attributes enable us to demonstrate, for the first time, the ratiometric imaging of endogenously produced HOCl in living cells by using these novel ratiometric probes. We expect that 1 a and 1 b will be useful molecular tools for studies of HOCl biology. In addition, the HOCl‐promoted cyclization reaction of rhodamine‐thiosemicarbazides to rhodamine‐oxadiazoles should be widely applicable for the development of different types of fluorescent HOCl probes.     

Pyridinium‐Fused Pyridinone: A Novel “Turn‐on” Fluorescent Chemodosimeter for Cyanide

A new chemodosimeter based on pyridinium‐fused pyridinone iodide ( PI ) has been obtained through a “clean reaction” method. This compound can detect CN^? in aqueous solution with a high selectivity and rapid response. The detection of CN^? occurs through the nucleophilic attack of CN^? on the C?N bond, which induces the destruction of the π‐conjugation on the pyridinium ring. Support of this detection mechanism was obtained by ¹H NMR titration, HR‐MS, and DFT calculations. Upon the addition of 10 equivalents CN^? to a solution of PI in THF/H₂O (1:1, v/v), a 57‐fold enhancement in fluorescence intensity was observed at the maximum emission wavelength of 457 nm. Meanwhile, the maximum absorption wavelength was also blue‐shifted from 447 nm to 355 nm. Other common anions such as BF₄^?, PF₆^?, F^?, Cl^?, Br^?, I^?, H₂PO₄^?, ClO₄^?, CH₃COO^?, NO₂^?, N₃^?, and SCN^? had little effect on the detection of CN^?. The response time of PI for CN^? was less than 5 seconds. The detection limit was calculated to be 5.4×10^?8 M , which is lower than the maximum permission concentration in drinking water (1.9 μM ) set by the World Health Organization (WHO).     

A Naphthalimide‐Based Fluorescence “Turn‐On” Probe for the Detection of Pb2+ in Aqueous Solution and Living Cells

An easily available naphthalimide‐based fluorescent probe NPA for Pb²⁺ detection was successfully developed. NPA exhibited an obvious fluorescence turn‐on response toward Pb²⁺ in aqueous solution and in living cells. Moreover, a series of model compounds were rationally designed and synthesized in order to explore the sensing mechanism and binding mode of NPA with Pb²⁺.     

Unravelling RNA–Substrate Interactions in a Ribozyme‐Catalysed Reaction Using Fluorescent Turn‐On Probes

The Diels–Alder reaction is one of the most important C?C bond‐forming reactions in organic chemistry, and much effort has been devoted to controlling its enantio‐ and diastereoselectivity. The Diels–Alderase ribozyme (DAse) catalyses the reaction between anthracene dienes and maleimide dienophiles with multiple‐turnover, stereoselectivity, and up to 1100‐fold rate acceleration. Here, a new generation of anthracene‐BODIPY‐based fluorescent probes was developed to monitor catalysis by the DAse. The brightness of these probes increases up to 93‐fold upon reaction with N‐pentylmaleimide (NPM), making these useful tools for investigating the stereochemistry of the ribozyme‐catalysed reaction. With these probes, we observed that the DAse catalyses the reaction with >91 % de and >99 % ee. The stereochemistry of the major product was determined unambiguously by rotating‐frame nuclear Overhauser NMR spectroscopy (ROESY‐NMR) and is in agreement with crystallographic structure information. The pronounced fluorescence change of the probes furthermore allowed a complete kinetic analysis, which revealed an ordered bi uni type reaction mechanism, with the dienophile binding first.     

A Nitro‐Functionalized Metal–Organic Framework as a Reaction‐Based Fluorescence Turn‐On Probe for Rapid and Selective H2S Detection

The toxic gas H₂S has recently emerged as one of the important signaling molecules in biological systems. Thus understanding the production, distribution, and mode of action of H₂S in biological system is important, but the fleeting and reactive nature of H₂S makes it a daunting task. Herein we report a biocompatible, nitro‐functionalized metal–organic framework as reaction‐based fluorescence turn‐on probe for fast and selective H₂S detection. The selective turn‐on performance of MOF remains unaffected even in presence of competing biomolecules.     

基于四丹磺酰胺杯[4]芳烃的汞离子荧光化学传感器

我们方便地合成了上沿修饰四丹磺酰胺基团的杯[4]芳烃衍生物1,发现该化合物在含50％水的乙腈中显示出对汞离子高选择性和灵敏性的识别作用,竞争实验表明多数金属离子对其检测干扰较小。机理研究结果表明荧光萃灭源于由丹磺酰胺基团到汞离子的光致电子转移过程。另外,通过研究1和1-Hg2+的荧光衰减实验,以及对比双丹磺酰胺杯[4]芳烃2和单丹磺酰胺杯[4]芳烃3对汞离子的识别作用,发现化合物1的四丹磺酰胺基团具有很好的预组织和协同作用。化合物1对汞离子的检测限为3.41×10-6 mol·L-1,这可以使1成为一个潜在的汞离子荧光化学传感器。     

Selective Fluorescence Turn‐On Sensing of Phosphate Anion in Water by Tetraphenylethylene Dimethylformamidine

A tetraphenylethylene (TPE) derivative bearing two dimethylformamidine units was synthesized. The dihydrogen chloride salt of this TPE derivative was soluble in water and showed almost no emission. By addition of phosphate anions, the dihydrogen chloride salt could be transformed into the monohydrogen chloride salt, which was barely soluble and emitted strong fluorescence through aggregation‐induced emission (AIE), while many other anions could not bring about a fluorescence enhancement. Meanwhile, the dihydrogen chloride salt and monohydrogen chloride salt could be reversible transformed by addition of acid and base alternately in the presence of phosphate anion, which led to fluorescence turn‐on and turn‐off. Therefore, the TPE dimethylformamidine holds potential for selectively sensing phosphate anions in water and use as fluorescence pH switch. This study provided a new approach to AIEgen sensors by using formamidine groups.