A multi-functional fluorescent sensor for Zn2+ and HSO4− based on a new diarylethene derivative

A new photochromic diarylethene derivative with a hydralazine unit was designed and synthesized. It was not only acted as a Zn²⁺ sensor with the fluorescent color change from dark blue to bright orange, but also acted as a fluorescent sensor for HSO₄^? with the fluorescent color change from dark blue to bright blue. Furthermore, the derivative also exhibits multi-addressable switching properties by the stimulations of lights and chemical reagents. Based on these characteristics, two combinational logic circuits were constructed with the emission intensity as the output signals, and the UV/vis lights, chemical species as the input signals.     

Naphthalene thiourea derivative based colorimetric and fluorescent dual chemosensor for F− and Cu2+/Hg2+ ions

A structurally simple (Z)-2-(naphthalen-2-ylmethylene)-N-phenylhydrazinecarbothioamide (R1) was used as a colorimetric and fluorescent sensor for both F^?  and Cu²⁺/Hg²⁺ ions. R1 selectively recognised F^?  ions as indicated by colour change from colourless to green. Fluorescence spectral data reveal that R1 is an excellent fluorescence chemosensor for Cu²⁺ ions. Finally, R1 was successfully applied to the bioimaging of Cu²⁺ ions in RAW 264.7 macrophage cells.     

Cooperative ion pair receptor based on tolan as a Li+/HSO4− selective extractor and fluorescent indicator

A new tolan derivative was synthesized as a selective ion pair receptor for LiHSO₄. The observed ion pair selectivity was accomplished by introducing aza-12-crown-4, which is size-selective for Li⁺. The ion pair receptor can function as an extractor and fluorescent indicator for LiHSO₄.     

A novel highly selective ratiometric fluorescent sensor for relay recognition of Zn2+ and H2PO4−

A novel fluorescent sensor (AQTF1) based on the N-(quinolin-8-yl) tetrahydrofuran-2-carboxamide was designed and synthesized. This new sensor demonstrated high selectivity for the Zn²⁺ without the interference from Cd²⁺. The detection limit of this probe was calculated to be 10.8 nM for Zn²⁺. The in situ prepared AQTF1-Zn²⁺ complex was used for detection of H₂PO₄^? and displayed good selectivity from the common anions. Furthermore, the AQTF1 displayed good ratiometric response for the relay recognition for Zn²⁺ and H₂PO₄^?.     

A self-assembled tetrapeptide that acts as a “turn-on” fluorescent sensor for Hg2+ ion

The tetrapeptide (Bz-$\mathrm{\Delta }$Phe(p-NPh₂)-l-DOPA(protected)-l-Phe-l-Phe-OMe was designed to incorporate seven phenyl rings so that it’s conformation, self-assembly and application in Hg²⁺ ions sensing could be studied. Peptide molecules adopted an overlapping β-turn of type III/III conformation in crystals. The peptide showed a highly selective turn-on response towards mercuric ion over other metal ions with a 10-fold enhancement in fluorescence intensity. This intensity change coupled with the selectivity of the peptide towards mercury allowed us to demonstrate simple colorimetric dip sensing of Hg²⁺ ions. The technique provides a highly selective and effective way to detect Hg²⁺ ions. The peptide also self-assembled into nanospheres with diameter ranges from 100 to 500?nm. Mercuric ion coordination enabled these peptide nanospheres to aggregate into well-defined nanoparticles. The enhanced fluorescence upon Hg²⁺ addition demonstrates that peptide scaffolds can be exploited in the development of different selective sensors.     

Single chemosensor for sensing multiple analytes: Selective fluorogenic detection of Cu2+ and Br−

A tripodal receptor R1 with a combination of nitrogen and oxygen-based binding sites was designed and used for the selective determination of Cu²⁺. The fluorescence emission profile of R1 in the presence of Cu²⁺ showed a marked enhancement in fluorescence intensity, indicating high selectivity among other metal ions. The R1–Cu²⁺ complex was further explored as a sensor for anion detection. Upon addition of Br^?, switching to a fluorescence “off” state was observed. The Br^? selectivity of the complex over a wide range of concentrations was observed via titrimetric analysis through changes in the emission spectra.     

A rapid selective colorimetric and ‘On–Off’ fluorimetric sensor for detecting Cu2+ ions in aqueous media based on a simple bis-schiff-base derivative

A simple colorimetric and fluorimetric ‘On–Off’ sensor L (3,3′-dimethyl -[1,1′-biphenyl]-4,4′-diyl)bis(azanylylidene)bis(methanylylidene)bis(naphthalen-2-ol) for Cu²⁺ ions bearing o-tolidine substituents has been designed and synthesised, and exhibits significant fluorimetric and colorimetric response for Cu²⁺ in DMSO/H₂O (8:2, v/v) HEPES buffer (pH 7.2) solution. The detection limit of the sensor towards Cu²⁺ is 7.25 × 10^? 8 M and the association constant K_a of 9.86 × 10⁴ M^? 1 was determined. Furthermore, other anions, including Fe³⁺, Hg²⁺, Ag⁺, Ca²⁺, Co²⁺, Ni²⁺, Cd²⁺, Pb²⁺, Zn²⁺, Cr³⁺ and Mg²⁺ have almost no influence on the probe's behaviour. Test strips based on the sensor L were fabricated, which could act as convenient and efficient Cu²⁺ test kits.     

Identification of exchange-coupled V4+ and Cu2+ ions in Cu?V?Mo oxide systems

ESR studies of X(CuO)·V₂O₅·8.3 MoO₃ (X=1–2) calcined in flowing nitrogen at 250–350 °C have revealed the exchange interaction of Cu²⁺ and V⁴⁺ ions that form a paramagnetic system.

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X(CuO) V₂O₅·8,3 MoO₃, X=1–2, , 250–350°C, Cu²⁺ V⁴⁺, .

     

A novel colorimetric and “turn-on” fluorescent sensor for selective detection of Cu2+

In this work, a new highly selective and sensitive fluorescent sensor for detecting Cu²⁺ was developed based on rhodamine fluorophore. It displayed strong fluorescence “turn-on” effect upon addition of Cu²⁺, and possessed the function of naked eye recognition. The fluorescence enhancement also enabled the sensor to quantitatively analyze Cu²⁺ due to the formation of a stable 1:1 metal–ligand complex in a short time, and the complex possesses relatively good pH stability. In addition, the density functional theory calculations were adopted to investigate the molecular orbitals as well as the spatial structure. Simultaneously, the cell imaging and zebra fish experiments provided a broader application prospect in biological system.     

Titration of AsO43? ions with 0.1 M magnesium sulphate solution in the presence of Ca2+, Mg2+, Fe3+, Cu2+ ions and some other foreign substances

Summary For the convenient and sufficiently accurate determination of AsO₄ ^3– ions in technical products containing different filling, suspending and colouring materials, as well as impurities—e.g. for the assay of arsenate containing plant protecting materials—the following procedure is recommended.About 5 g of the sample is dissolved, resp. extracted with 4 N hydrochloric acid, and aliquots of the clear filtrate are titrated after elimination of the interfering metal ions by combining them with complexing agents (potassium cyanide and disodium ethylenediamin tetraacetic acid) in a properly buffered medium. The titration with 0.1 M MgSO₄ solution is conducted in the presence of eriochrome black T solution as indicator, first time for eliminating the excess of EDTA added, and afterwards to determine the AsO₄ ^3– ions, after adding about 40% of ethanol.The procedure may be useful chiefly for serial routine analyses.The authors are indebted to engineer L. Fokássy, department leader at the State Institute for Agricultural Quality Control, as well as to engineeress P. Fodor and Mr. Gy. Josepovits, scientific collaborators of the Research Institute for Plant Protection, for kindly supplying some of the samples for the experiments.     

脯氨酸与Cu、Cu+和Cu2+配位体系的计算研究

运用M06-2X和ωB97XD方法分别在6-311++G（2d,p）和TZVP基组水平上,对脯氨酸（Pro）的15种构象与Cu、Cu⁺和Cu²⁺形成的多种配合物的几何结构、能量学特征、振动光谱和电子结构等进行计算研究. 四种水平得到20种[Pro-Cu]、16种[Pro-Cu]⁺和16种[Pro-Cu]²⁺稳定结构. [Pro-Cu]和[Pro-Cu]⁺体系中出现12种Pro构象,而[Pro-Cu]²⁺体系中出现11种Pro构象,三种体系中最稳定的结构都不是由能量最低的Pro构象生成的. 在结构CI3、CI4、CII7和CII8中,Pro的羧基氢转移到亚氨基氮形成两性离子与Cu双配位结合. [Pro-Cu]^0/1+/2+体系四种水平计算相对能差范围逐渐增加,结合能分别在-60.0 --5.0 kJ·mol^-1、-340.0 --170.0 kJ·mol^-1和-1100.0 --860.0 kJ·mol^-1范围,配位体系中Pro的变形能逐渐增加. N―H和O―H键伸缩振动频率普遍发生红移,配位体系中部分电荷从Pro转移到Cu上,在[Pro-Cu]²⁺体系中单配位结构中电荷转移最多,约为单位负电荷.     

A Zn(II) luminescent polymer as a multifunctional sensor to nitrobenzene,Fe3+ and CrO42− ions

A metal-organic framework of {[Zn(tib)₂]·2NO₃} (tib = 135-tris(1-imidazolyl)benzene) (1) has been synthesized and characterized. The structure determination reveals that 1 is a 2-D layer network and exhibits a classical hxl topology. 1 shows selective properties in the detection of nitrobenzene and Fe³⁺. Furthermore, 1 also exhibits an excellent capability to detect CrO₄^2?. The present work indicates that 1 could be taken as a potential candidate for developing multifunctional luminescence sensors.     

A multi-responsive diarylethene-rhodamine 6G derivative for sequential detection of Cr3+ and CO32−

A new unsymmetrical diarylethene derivative (1o) with rhodamine 6G as a functional group has been designed and synthesized. It displayed good physicochemical properties induced by lights and chemical stimuli. 1o could sensitively detect towards Cr³⁺ with a 1:1 stoichiometry, and exhibit an obviously fluorescence (from dark to light cyan) and color (from colorless to pink) changes during the recognition process. The limit of detection was determined to be 27?nM and 8.5?nM via UV/vis and fluorescence methods, respectively. More importantly, the resulting complex 1o-Cr³⁺ (1o') could be served as a potential fluorescent probe to selectively and sensitively recognize toward CO₃^2?, the limit of detection was determined to be 0.88?μM and 0.26?μM via UV/vis and fluorescence methods, respectively. Moreover, the quenching of fluorescence intensity can reach 95% due to the perfect FRET processes between the excited open-ring rhodamine 6G moiety and the closed-ring diarylethene unit.     

同时识别Cu2+,Zn2+和Ca2+的化学传感器合成及Ca2+活体荧光成像

合成并表征了一个能同时对Cu²⁺,Zn²⁺和Ca²⁺进行识别的化学传感器L,研究了L对常见的金属离子和阴离子的吸收光谱和荧光光谱。结果发现：L可通过紫外-可见吸收光谱分别在414和328 nm处对Cu²⁺,Zn²⁺进行特异识别,L可通过在511 nm处的荧光增强对Ca²⁺进行特异识别,且其识别具有快速、可选择及可逆的特点。将L应用于药品和水体样品中Cu²⁺,Zn²⁺和Ca²⁺的检测,结果满意。L还可用荧光成像对细胞和活体中Ca²⁺进行检测。     

A new “naked-eye” colorimetric and ratiometric fluorescent sensor for imaging Hg2+ in living cells

A new oligothiophene-based sensor 3 TH for monitoring Hg²⁺ has been designed and synthesized based on the intramolecular charge transfer (ICT) mechanism. The 3 TH shows the significant specificity toward Hg²⁺ through “naked-eye” colorimetric detection as well as via ratiometric fluorescence enhancement response with low detection limit of 62 nM. In addition, sensor 3 TH shows high selectivity and sensitivity for Hg²⁺ with fast response in a suitable pH range. Moreover, the 3 TH-based test strips was used to conveniently detect Hg²⁺ ions in water. Furthermore, considering its good ‘‘turn-on’’ fluorescent sensing behavior and low cell cytotoxicity, 3 TH was successfully applied to detect and image Hg²⁺ in real water samples and living cells, which shows great potentials for application in environmental and biological systems.     

A simple colorimetric chemosensor for relay detection of Cu2+ and S2− in aqueous solution

A simple colorimetric chemosensor 1 was developed for the sequential detection of Cu²⁺ and S^2?. Sensor 1 could rapidly detect Cu²⁺ by an obvious color change from colorless to yellow. The binding mode of 1 to Cu²⁺ was determined to be a 1:1 complexation stoichiometry through Job plot and ESI-mass spectrometry analyses. The sensing mechanism of Cu²⁺ by 1 was proposed by theoretical calculations. Importantly, the detection limit for Cu²⁺ was found to be 0.12 μM, which was much lower than the recommended value (31.5 μM) of the World Health Organization (WHO). Additionally, 1 could detect and quantify Cu²⁺ in real water samples. Moreover, the resulting 1-Cu²⁺ complex could be used as a highly selective colorimetric sensor for S^2? in the presence of various anions without any interference. The detection limit for S^2? was determined to be 1.66 μM, which was much lower than the guideline (14.8 μM) recommended by WHO in fresh water.     

A dual chemosensor for Cu2+ and Fe3+ based on π-extend tetrathiafulvalene derivative

A new dual chemosensor (TTF-PBA) for Fe³⁺ and Cu²⁺ in different signal pathways was designed and synthesized. The absorption spectrum, fluorescence spectrum and cyclic voltammograms changed in the presence of Cu²⁺ and Fe³⁺. The optical color changed within 5 s from yellow to orange upon the addition of Cu²⁺, and it changed to dark yellow when Fe³⁺ existed. The cyclic voltammogram of Cu²⁺/TTF-PBA changed from E_ox = 0.50 V, E_red = 0.32 V to E_ox = 0.64 V, E_red = 0.80 V (vs Ag/AgCl) upon the addition of 2.0 equiv. Cu²⁺. As for Fe³⁺/TTF-PBA, its oxidation wave disappeared, and its reduction wave appeared at E_red = ?0.59 V (vs Ag/AgCl) upon the addition of 4.0 equv. Fe³⁺. The sensor displayed high selectivity for Cu²⁺ and Fe³⁺ over other ions including Pb²⁺, Zn²⁺, Ni²⁺, Ag⁺, Cr³⁺, Mn²⁺, Al³⁺, Co²⁺, Pd²⁺, Hg²⁺, Fe^2+, Cd²⁺, Ce³⁺, Bi³⁺ and Au³⁺, the detection limits for Cu²⁺ and Fe³⁺ ion reached as low as 5.33 × 10^?7 mol/L and 5.34 × 10^?7 mol/L, respectively. Furthermore, when Fe³⁺ existed, Cu²⁺ can be detected sequentially by the sensor through the absorption spectrum and the color change observed by naked-eyes.     

A highly selective turn-on colorimetric and luminescence sensor based on a triphenylamine-appended ruthenium(Ⅱ) dye for detecting mercury ion

A dual colorimetric and luminescent sensor based on a heteroleptic ruthenium dye[Ru(Hipdpa)(Hdcbpy)(NCS)_2]~-·0.5H~+ 0.5[N(C_4H_9)_4]~+ Ru(Hipdpa) {where Hdcbpy = monodeprotonted-4,4'-dicarboxy-2.2'-bipyridineand Hipdpa = 4-(1H-imidazo[4,5-f][l,10]phenanthroIin-2-yl)-N,N-diphenylaniIine} for selective detection of Hg~(2+) is presented.The results of spectrophotometric titrations revealed an evident luminescence intensity enhancement(I/I_0 =11) and a considerable blue shift in visible absorption and luminescence maxima with the addition of Hg~(2+).The sensitive response of the optical sensor on Hg~(2+) was attributed to the binding of the electron-deficient Hg~(2+) to the electron-rich sulfur atom of the thiocyanate(NCS) ligand in the Ru(Hipdpa).which led to an increase in the energy gap between the highest occupied molecular orbital(HOMO) and the lowest unoccupied molecular orbital(LUMO).Accordingly,the blue shift in the absorption spectrum of Ru(Hipdpa) due to the binding of Hg~(2+) was obtained.Ru(Hipdpa) was found to have decreased Hg~(2+) detection limit and improved linear region as compared to di(tetrabutylammonium) ris-bis(isothiocyanato)bis(2,2'-bipyridine-4-carboxylic acid-4'-carboxylate)ruthenium(Ⅱ) N719.Moreover,a dramatic color change from pink to yellow was observed,which allowed simple monitoring of Hg~(2+) by either naked eyes or a simple colorimetric reader.Therefore,the proposed sensor can provide potential applications for Hg~(2+) detection.