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1.
We developed a new chromogenic and fluorescent ‘turn‐on’ chemodosimeter 1 based on a F‐triggered cascade reaction. This system displayed significant changes in UV/vis absorption and fluorescence emission intensities selectively for F over other anions in a mixture of CH3CN/H2O (95 : 5, v/v) and in acetonitrile. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

2.
A novel blue luminescent 6‐chloro‐2‐(4‐cynophenyl) substituted diphenyl quinoline (Cl‐CN DPQ) organic phosphor has been synthesized by the acid‐catalyzed Friedlander reaction and then characterized to confirm structural, optical and thermal properties. Structural properties of Cl‐CN‐DPQ were analyzed by Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR) spectroscopy, X‐ray diffraction technique (XRD) and scanning electron microscopy (SEM) and energy dispersive analysis of X‐ray (EDAX) spectroscopy. FTIR spectra confirmed the presence of different functional groups and bond stretching. 1H–NMR and 13C–NMR confirmed the formation of an organic Cl‐CN‐DPQ compound. X‐ray diffraction study provided its crystalline nature. The surface morphology of Cl‐CN‐DPQ was analyzed by SEM, while EDAX spectroscopy revealed the elemental analysis. Differential thermal analysis (TGA/DTA) disclosed its thermal stability up to 250°C. The optical properties of Cl‐CN‐DPQ were investigated by UV–vis absorption and photoluminescence (PL) measurements. Cl‐CN‐DPQ exhibits intense blue emission at 434 nm in a solid‐state crystalline powder with CIE co‐ordinates (0.157, 0.027), when excited at 373 nm. Cl‐CN‐DPQ shows remarkable Stokes shift in the range 14800–5100 cm?1, which is the characteristic feature of intense light emission. A narrow full width at half‐maximum (FWHM) value of PL spectra in the range 42–48 nm was observed. Oscillator strength, energy band gap, quantum yield, and fluorescence energy yield were also examined using UV–vis absorption and photoluminescence spectra. These results prove its applications towards developing organic luminescence devices and displays, organic phosphor‐based solar cells and displays, organic lasers, chemical sensors and many more.  相似文献   

3.
A novel fluorescent probe‐based naphthalene Schiff, 1‐(C2‐glucosyl‐ylimino‐methyl)‐naphthalene‐2‐ol (L) was synthesized by coupling d ‐glucosamine hydrochloride with 2‐hydroxy‐1‐naphthaldehyde. It exhibited excellent selectivity and highly sensitivity for Al3+ in ethanol with a strong fluorescence response, while other common metal ions such as Pb2+, Mg2+, Cu2+, Co2+, Ni2+, Cd2+, Fe2+, Mn2+, Hg2+, Li+, Na+, K+, Fe3+, Cr3+, Zn2+, Ag+, Ba2+ and Ca2+ did not cause the same fluorescence response. The probe selectively bound Al3+ with a binding constant (Ka) of 5.748 × 103 M?1 and a lowest detection limit (LOD) of 4.08 nM. Moreover, the study found that the fluorescence of the L ? Al3+ complex could be quenched after addition of F? in the same medium, while other anions, including Cl?, Br?, I?, NO2?, NO3?, ClO4?, CO32?, HCO3?, SO42?, HSO4?, CH3COO?, PO43?, HPO42?, S2? and S2O32? had nearly no influence on probe behaviour. Binding of the [L ? Al3+] complex to a F? anion was established by different fluorescence titration studies, with a detection limit of 3.2 nM in ethanol. The fluorescent probe was also successfully applied in the imaging detection of Al3+ and F? in living cells.  相似文献   

4.
A new fluorescent Al3+‐probe, N‐allyl‐4‐[3,3′‐((2‐aminoethyl)azanediyl)‐bis(N´‐(2‐hydroxybenzylidene)propanehy‐drazide)]‐1,8‐naphthalimide ( L ), was designed and synthesized based on 1,8‐naphthalimide. The probe L contains 1,8‐naphthalimide moiety as the fluorophore and a Schiff base as the recognition group. The structure of L was determined by single crystal X‐ray. L emission at 526 nm increased on addition of Al3+ under excitation wavelength at 350 nm. L exhibited high selectivity and sensitivity fluorescence emission towards to Al3+ in ethanol/Tris–HCl buffer solution (1:1, v/v, pH = 7.2) as compared with other tested metal ions. A good linearity with a correlation coefficient (R2) of 0.99 was observed in the concentration range 2–10 μM. The binding constant and the detection limit of L for Al3+ were calculated to 2.6 × 104 M?1 and 0.34 μM, respectively. The results of experiments that including Job plot, ultraviolet–visible (UV–Vis) light titration, fluorescence titration, ESI‐MS and 1H NMR titration, indicated a 1:1 stoichiometric complex between L and Al3+. L was highly effective in monitoring Al3+ in real‐life Yellow River and tap water samples.  相似文献   

5.
Here, we present a new bipyridyl moiety linked Schiff base (bipy‐1) that is well characterized using spectroscopic techniques. Colorimetric and UV‐vis titrations were used to study the photophysical properties of bipy‐1 in the presence of various tetrabutyl ammonium salt of anions and metal salts containing different counter cations. bipy‐1 showed selective recognition of dimethyl sulphoxide solution of tetrabutyl ammonium salt of F? ion accompanied with a UV‐vis band at 529 nm and interesting binding of aqueous Co, Ni, and Cu acetates/fluorides, as confirmed by distinct color changes from fluorescent green to pink or orange and a strong band around 480–510 nm in the UV‐vis spectrum. However, in the presence of Co, Ni, and Cu countercations, any form of metal acetate/fluorides was found to be able to respond to similar color changes from fluorescent green to pink or orange, showing a band around 480–510 nm. This type of output clearly indicates that the in situ formation of Co, Ni, and Cu acetates/fluorides also coordinates with bipyridyl nitrogen atoms. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

6.
A series of artificial receptors, hydrazone derivatives containing anthracene, have been designed and synthesized. The interaction of these receptors with biologically important anions was determined by UV–vis, fluorescence and 1H NMR titration experiments and theoretical investigation. Results indicate that the receptor (1) without NO2 shows no binding ability for various anions. The other receptors (2 and 3) show the highest binding ability for acetate (AcO) among studied anions (fluoride (F), dihydrogen phosphate (H2PO4), chloride (Cl), bromide (Br), iodide (I)); and the binding ability for AcO is not interfered by the existence of other anions. The additions of AcO, F and H2PO4 can arouse different degrees of fluorescence quenching. 1H NMR titration shows that the interaction between the receptor 2 and F firstly depends on the hydrogen-bond formation; later the interacted site NH is deprotonated and the added F forms hydrogen bond with the near CH in Schiff base. Moreover, visual color changes accompany guest binding, enabling this system to act as colorimetric anion sensors.  相似文献   

7.
Polyvinyl pyrrolidone (PVP) crowned chrysene nanoparticles (CHYNPs) were prepared by using a reprecipitation method. Dynamic light scattering (DLS) and scanning electron microscope (SEM) studies indicate that the monodispersed spherical nanoparticles bear a negative charge on their surfaces. The bathochromic spectral shift in the UV–visible and fluorescence spectrum of CHYNPs from chrysene (CHY) in acetone solution supports the J‐ type aggregation of nanoparticles. The aggregation‐induced enhanced emission of CHYNPs at 486 and 522 nm decreases by increasing the concentration of the Ca2+ ion solution. It can display an ON–OFF type fluorescence response with high selectivity towards Ca2+ ions aqueous medium. Furthermore, the in situ generated PVP–CHYNPs–Ca2+ ensemble could recover the quenched fluorescence upon the addition of fluoride anions resulting in an OFF–ON type sensor. The present method has a correlation coefficient R2 = 0.988 with a detection limit of 1.22 μg/mL for Ca2+ in the aqueous medium. The fluorescence changes of PVP crowned CHYNPs upon the addition of Ca2+ and F? can be utilized as an INHIBIT logic gate at the molecular level, using Ca2+ and F? chemical inputs and the fluorescence intensity signal as output.  相似文献   

8.
Minimizing electrolyte use is essential to achieve high practical energy density of lithium–sulfur (Li–S) batteries. However, the sulfur cathode is more readily passivated under a lean electrolyte condition, resulting in low sulfur utilization. In addition, continuous electrolyte decomposition on the Li metal anode aggravates the problem, provoking rapid capacity decay. In this work, the dual functionalities of NO3? as a high‐donor‐number (DN) salt anion is presented, which improves the sulfur utilization and cycling stability of lean‐electrolyte Li–S batteries. The NO3? anion elevates the solubility of the sulfur species based on its high electron donating ability, achieving a high sulfur utilization of above 1200 mA h g?1. Furthermore, the anion suppresses electrolyte decomposition on the Li metal by regulating the lithium ion (Li+) solvation sheath, enhancing the cycle performance of the lean electrolyte cell. By understanding the anionic effects, this work demonstrates the potential of the high‐DN electrolyte, which is beneficial for both the cathode and anode of Li–S batteries.  相似文献   

9.
Nonaqueous metal–gas batteries based on halogenated reactants exhibit strong potential for future high‐energy electrochemical systems. The lithium–sulfur hexafluoride (Li–SF6) primary battery, which utilizes a safe, noncombustible, energy‐dense gas as cathode, demonstrates attractive eight‐electron transfer reduction during discharge and high attainable capacities (>3000 mAh g?1carbon) at voltages above 2.2 VLi. However, improved rate capability is needed for practical applications. Here, two viable strategies are reported to achieve this by targeting the solubility of the passivating discharge product, lithium fluoride (LiF). Operating at moderately elevated temperatures, e.g., 50 °C, in DMSO dramatically improves LiF solubility and promotes sparser and larger LiF nuclei on gas diffusion layer electrodes, leading to capacity improvements of ≈10× at 120 µA cm?2. More aggressive chemical modification of the electrolyte by including a tris(pentafluorophenyl)borane anion receptor further promotes LiF solubilization; capacity increases even at room temperature by a factor of 25 at 120 µA cm?2, with attainable capacities up to 3 mAh cm?2. This work shows that bulk fluoride‐forming conversion reactions can be strongly manipulated by tuning the electrolyte environment to be solvating toward F?, and that significantly improved rates can be achieved, leading a step closer to practical applications.  相似文献   

10.
The photocatalytic reduction of nitrogen (N2) with water (H2O) as the reducing agent holds great promise as a sustainable future technology for the synthesis of ammonia (NH3). Herein, the effect of oxygen vacancies and electron‐rich Cuδ+ on the performance of zinc‐aluminium layered double hydroxide (ZnAl‐LDH) nanosheet photocatalysts for N2 reduction to NH3 under UV–vis excitation is systematically explored. Results show that a 0.5%‐ZnAl‐LDH nanosheet photocatalyst (containing 0.5 mol% Cu by metal basis) affords a remarkable NH3 production rate of 110 µmol g?1 h?1 and excellent stability in pure water. The X‐ray absorption spectroscopy, electron paramagnetic resonance, and density functional theory calculations reveal that Cu addition imparts oxygen vacancies and coordinatively unsaturated Cuδ+ (δ < 2) with electron‐rich property in the ZnAl‐LDH nanosheets, both of which readily contribute to efficient separation and transfer of photogenerated electrons and holes and promote N2 adsorption, thereby both activating N2 and facilitating its multielectrons reduction to NH3.  相似文献   

11.
A new typical phenothiazine compound functionalized with thienyl‐indandione derivative (PTZTID) was synthesized and characterized using spectral analysis (ultraviolet–visible (UV–vis) light, infrared (IR), 1H nuclear magnetic resonance (NMR) and 13C NMR tools). The UV–vis absorption spectra of the PTZTID solution in 1,4‐dioxane showed two absorption bands attributed to localized aromatic π–π* transitions of conjugated aromatic moieties and intramolecular charge transfer with the characteristics of a π–π* transition. The fluorescence spectra exhibited a maximum emission wavelength at 580 nm. The effect of concentration on photophysical properties took the form of a minor hypsochromic shift, which was attributed to some extent to the occurrence of H‐type aggregation of the PTZTID derivative. Binary solvent effects on the spectroscopic behaviour of PTZTID were measured at different H2O/1,4‐dioxane ratios. Similarly, when increasing the water content, a hypsochromic shift was observed that resulted from H‐type aggregation. Furthermore, geometry and electronic configurations of PTZTID were studied at density functional theory /B3LYP level and indicated that the compound had a nonplanar (butterfly structure).  相似文献   

12.
Amongst post‐Li‐ion battery technologies, lithium–sulfur (Li–S) batteries have captured an immense interest as one of the most appealing devices from both the industrial and academia sectors. The replacement of conventional liquid electrolytes with solid polymer electrolytes (SPEs) enables not only a safer use of Li metal (Li°) anodes but also a flexible design in the shape of Li–S batteries. However, the practical implementation of SPEs‐based all‐solid‐state Li–S batteries (ASSLSBs) is largely hindered by the shuttling effect of the polysulfide intermediates and the formation of dendritic Li° during the battery operation. Herein, a fluorine‐free noble salt anion, tricyanomethanide [C(CN)3?, TCM?], is proposed as a Li‐ion conducting salt for ASSLSBs. Compared to the widely used perfluorinated anions {e.g., bis(trifluoromethanesulfonyl)imide anion, [N(SO2CF3)2)]?, TFSI?}, the LiTCM‐based electrolytes show decent ionic conductivity, good thermal stability, and sufficient anodic stability suiting the cell chemistry of ASSLSBs. In particular, the fluorine‐free solid electrolyte interphase layer originating from the decomposition of LiTCM exhibits a good mechanical integrity and Li‐ion conductivity, which allows the LiTCM‐based Li–S cells to be cycled with good rate capability and Coulombic efficiency. The LiTCM‐based electrolytes are believed to be the most promising candidates for building cost‐effective and high energy density ASSLSBs in the near future.  相似文献   

13.
Luminescent nanoparticles of Y2O3 doped with europium (Eu) and/or titanium (Ti) were synthesized using modified sol–gel routes. The crystalline cubic phase was confirmed using X‐ray powder diffraction (XRD). Particle morphology and size were evaluated using scanning and transmission electron microscopy. High‐resolution transmission electron microscopy showed that the synthesis method affected the average particle size and the Fourier transform of the images showed the lattice plane distances, indicating that the samples presented high crystallinity degree in accordance with the XRD pattern. The Ti valence was investigated using X‐ray absorption near edge spectroscopy and the tetravalent form was the dominant oxidizing state in the samples, mainly in Eu and Ti co‐doped Y2O3. Optical behaviour was investigated through X‐ray excited optical luminescence and photoluminescence under ultraviolet–visible (UV–vis) and vacuum ultraviolet (VUV) excitation. Results indicated that Eu3+ is the emitting centre in samples doped with only Eu and with both Eu and Ti with the 5D07F2 transition as the most intense, indicating Eu3+ in a noncentrosymmetric site. Finally, in the Eu,Ti‐doped Y2O3 system, Ti3+ (or TiIV) excitation was observed but no Ti emission was present, indicating a very efficient energy transfer process from Ti to Eu3+. These results can aid the development of efficient nanomaterials, activated using UV, VUV, or X‐rays.  相似文献   

14.
In this work, 4‐(p ‐hydroxybenzylidenehydrazino)‐N ‐butyl‐1,8‐naphthalimide ( 1 ) has been designed and synthesized as a colorimetric and fluorescent dual‐modal probe for F?. Compound 1 immediately detected inorganic fluoride salts using UV /v is absorption and fluorescence spectroscopy methods, and served as a ‘naked‐eye’ indicator for F? with high selectivity and sensitivity. Both the absorption and fluorescence spectra show excellent linearity with the concentration of F?. Real‐life applications demonstrated that our proposed analytical system provided a satisfactory method for the determination of F?. In addition, the reaction mechanism of deprotonation was confirmed by 1H NMR.  相似文献   

15.
In this work, a simple and selective fluorescence sensor approach called ‘turn‐on–off’ for the determination of thiamine (TM) has been developed. As known, the o‐phenanthroline (o‐phen) has inner fluorescence, though when reacted with zinc ions to form the o‐phen–Zn2+ complex the fluorescence intensity was enhanced effectively, while upon addition of TM into the o‐phen–Zn2+ complex solution, the intensity of the system was gently quenched, which was termed the ‘turn‐on–off’ probe. Notably, the method possessed highly selective, sensitive determination for TM with a detection limit of 0.25 μmol L?1 and the reduced fluorescence intensity was proportional to the concentration of TM in the range 0.84–80.0 μmol L?1. Besides, the proposed mechanism was also investigated through exploring the Fourier transform infrared (FT‐IR), nuclear magnetic resonance (NMR) spectroscopy. Furthermore, this manner was successfully applied into practical samples for TM detection with satisfactory results.  相似文献   

16.
The title compound of 3‐benzothiazole‐9‐ethyl carbazole was synthesized by the reaction of 3‐aldehyde‐9‐ethyl carbazole and 2‐aminothiophenol. The compound was characterized by 1H nuclear magnetic resonance (NMR) and mass spectrometry (MS). Its crystal structure was obtained and determined by single crystal X‐ray diffraction. The results showed that the crystal belongs to the orthorhombic crystal system and the cell parameters of space group P2(1)2(1)2(1) were a = 5.6626 (12) Å, b = 12.606 (3) Å, c = 22.639 (5) Å, α = 90°, β = 90°, γ = 90°, V = 1616.0 (6) Å3, Z = 4, Dc = 1.350 mg/m3. The UV–vis and fluorescence spectra were also studied preliminarily. The fluorescence spectra of the title compound with bovine serum albumin (BSA) showed that BSA could be marked with the compound and the stability constant between them was 0.82 × 107 M?1. Meanwhile, the crystal and molecule were theoretically surveyed by density functional tight‐binding (DFTB). The results showed that there was an orbital overlap for lowest unoccupied molecular orbital (LUMO) between the neighbouring molecules for the crystal, which is different from the molecule structure. It was also showed that the crystal structure is a non‐conductor. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

17.
A series of artificial 2,2′-bipyridine receptors (1, 2, 3) containing phenol group have been designed and synthesized. Their anion-binding properties are evaluated for various anions (F?, Cl?, Br?, I?, AcO? and H2PO4?) by UV-vis titration experiment in order to research the impact of different substituents on anion-recognition properties. Results indicate that the anion binding abilities can be tuned by electron push-pull properties of substituents on the phenyl ortho- or para-position of the receptors. In addition, receptor 1 is sensitive for F? detection without the interference of other studied anions, and receptors 2 and 3 are sensitive for H2PO4? detection.  相似文献   

18.
1,3‐Diphenyl‐5‐(9‐anthryl)‐2‐pyrazoline and 1,3‐diphenyl‐5‐(9‐anthryl)‐1H‐pyrazole with an anthryl chromophore were synthesized and characterized using 1H NMR, 13C NMR, FT‐IR, mass spectrometry and elemental analysis. Their optical properties were characterized by UV–vis absorption and fluorescence spectroscopy. It was observed that the absorption and fluorescence spectra of the two compounds showed a red shift with respect to that of anthracene. Pyrazole exhibited high fluorescent quantum yields (Φf = 0.90 in toluene) while pyrazoline showed nearly no fluorescence in solution. The significant fluorescence divergence of the two similar compounds was investigated theoretically through density functional theory (DFT) calculations. The energetically lowest‐lying state S1 in the pyrazoline exhibited both characteristics of locally excited and electron‐transfer states that resulted in the fluorescence quenching of anthryl chromophore whereas the S1 state in the pyrazole corresponded to an optically allowed state that led to high fluorescence quantum yields in solutions. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

19.
The bloom‐forming cyanobacterium Microcystis aeruginosa (Kütz.) Kütz. 854 was cultured with 1.05 W · m?2 ultraviolet‐B radiation (UVBR) for 3 h every day, and the CO2‐concentrating mechanism (CCM) within this species as well as effects of UVBR on its operation were investigated. Microcystis aeruginosa 854 possessed at least three inorganic carbon transport systems and could utilize external HCO3? and CO2 for its photosynthesis. The maximum photosynthetic rate was approximately the same, but the apparent affinity for dissolved inorganic carbon was significantly decreased from 74.7 μmol · L?1 in the control to 34.7 μmol · L?1 in UVBR‐treated cells. At 150 μmol · L?1 KHCO3 and pH 8.0, Na+‐dependent HCO3? transport contributed 43.4%–40.2% to the photosynthesis in the control and 34.5%–31.9% in UVBR‐treated cells. However, the contribution of Na+‐independent HCO3? transport increased from 8.7% in the control to 18.3% in UVBR‐treated cells. The contribution of CO2‐uptake systems showed little difference: 47.9%–51.0% in the control and 49.8%–47.2% in UVBR‐treated cells. Thus, the rate of total inorganic carbon uptake was only marginally affected, although UVBR had a differential effect on various inorganic carbon transporters. However, the number of carboxysomes in UVBR‐treated cells was significantly decreased compared to that in the control.  相似文献   

20.
Novel phenanthroline Schiff base fluorescent sensors L1 , L2 , and D1 were designed and synthesized. The sensing abilities of the compounds in the presence of metal cations (Li+, Na+, K+, Ag+, Mg2+, Ba2+, Ca2+, Mn2+, Pb2+, Hg2+, Ni2+, Zn2+, Cd2+, Co2+, Cu2+, Cr3+, Fe3+, Fe2+, Al3+, and Eu3+) were studied by UV‐vis and fluorescent spectroscopy. The compounds L1 , L2 , and D1 could act as Eu3+ ion turn‐off fluorescent sensors based on ligand‐to‐metal binding mechanism in DMSO‐H2O solution (v/v = 1:1, 10 mM Tris, pH = 7.4). Additionally, the L1 –Eu3+ and D1 –Eu3+ complexes could be applied as turn‐on enantioselective sensors sensing of malate anion isomers with color changes. Furthermore, biological experiments using living PC‐12 cells demonstrated that L1 and D1 had excellent membrane permeability and could be used as effective fluorescent sensors for detecting Eu3+ and malate anion in living cells.  相似文献   

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